US20160220348A1

US20160220348A1 - Refractive-diffractive ophthalmic device and compositions useful for producing same

Info

Publication number: US20160220348A1
Application number: US15/095,078
Authority: US
Inventors: Sanjay Ram Swaroop Argal; Munawar Tahir HUSSAIN; Vinod Chintamani Malshe; Abhijit Bhagvat Patil
Original assignee: DAVE JAGRAT NATAVAR
Current assignee: DAVE JAGRAT NATAVAR
Priority date: 2010-07-05
Filing date: 2016-04-10
Publication date: 2016-08-04
Also published as: EP2591026A2; WO2012004744A3; WO2012004746A2; EP2591025B1; US9622853B2; US20130107201A1; US9310624B2; ES2585632T3; EP2591026B1; WO2012004746A8; EP2591025A2; US20130109779A1; US20170181847A1; WO2012004744A2; WO2012004746A3; WO2012004744A8

Abstract

Provided herein is a multifocal ophthalmic device comprising a lens body being formed with a plurality of concentric annular zones separated by slanted steps which effect both diffraction and refraction of incident light, while being devoid of any diffractive or refractive power, whereas the lens body is made from a co-polymeric composition based on less than 75% aromatic acrylate monomers, and includes a curcuminoid compound as a UV-light stabilizer; as well as use of the device for treating ophthalmologic and/or esthetic condition associated with an eye.

Description

RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No. 13/808,624 filed on Jan. 7, 2013, which is a National Phase of PCT Patent Application No. PCT/IB2011/052978 having International filing date of Jul. 5, 2011, which claims the benefit of priority of India Patent Application Nos. 1938/MUM/2010 filed on Jul. 5, 2010, 2888/MUM/2010 filed on Oct. 18, 2010 and 273/MUM/2011 filed on Feb. 1, 2011. The contents of the above applications are all incorporated by reference as if fully set forth herein in their entirety.

FIELD AND BACKGROUND OF THE INVENTION

The present invention, in some embodiments thereof, relates to ophthalmic and ocular devices, and more particularly, but not exclusively, to multifocal ophthalmic devices made of polymeric or co-polymeric compositions.
Light is an electromagnetic wave emitted by excited electrons; and as such can reflect, refract and diffract.
The human eye is a complex anatomical device, which evolved to interact with light and facilitates interpretation of shapes, colors, dimensions and relative position of objects by processing the light they reflect or emit. Similarly to a camera, the eye is able to refract light and produce a focused image that can stimulate neural responses and provide the ability to see. The iris regulates the amount of light admitted to the interior of the eye, the cornea and the lens focus the light rays from an object being viewed onto the retina which transmits the image of the object to the brain via the optic nerve. About 75% of the focusing is provided by the cornea, with the other 25% provided by the crystalline lens which may acquire variable focal lengths.
The cornea is the most anterior structure of the eye. Since it has to be transparent to allow light to enter the eye, there are no blood vessels in the cornea. The cornea is composed of collagen fibers packed together in an organized pattern, thereby providing the cornea its light transparent nature. The cornea has the highest concentration of nerve endings in the entire body, thus making it extremely sensitive to any kind of trauma. The front view of the cornea is of an aspheric shape, where the vertical dimension is smaller than the horizontal dimension by about 1-2%. The anterior is typically about 11.7 mm in diameter.
The quality of vision depends on many factors including the size and shape of the eye, and the transparency of the cornea and lens. When age or disease causes the lens to become less transparent, vision deteriorates because of the diminished light which can be transmitted to the retina. This deficiency in the lens of the eye is medically known as a cataract. An accepted treatment for this condition is a surgical replacement of the lens.
Corrective optic devices are used to correct refractive errors of the eye by modifying the effective focal length of the lens in order to alleviate the effects of conditions such as nearsightedness (myopia), farsightedness (hyperopia) or astigmatism. Another common condition in older patients is presbyopia which is caused by the eye's crystalline lens losing transparency (cataract) and/or elasticity, progressively reducing the ability of the lens to accommodate, namely to focus on objects close to the eye.
Corrective optic devices, also referred to herein as ophthalmic devices, include, for example, contact lenses and IOLs (intraocular lens, an implanted lens in the eye, usually replacing the existing crystalline lens because it has been clouded over by a cataract, or as a form of refractive surgery to change the eye's optical power), keratoprostheses, corneal rings, phakic lenses, aphakic lenses, capsular bag extension rings, corneal inlays and corneal onlays. Corrective optic devices for refractive errors also include eyeglasses, sunglasses or spectacles, comprising frames bearing lenses which are worn in front of the eyes normally for vision correction, eye protection, or for protection from UV rays.
Ophthalmic devices include cornea implants for artificial keratoplasty (keratoprostheses), cornea onlay lenses (contact lenses) or corneal inlay lenses or rings for correcting refractive errors, intraocular lenses for cataract surgery, phakic intraocular lenses in the posterior chamber of eye and lenses for optical instruments. Generally, such devices operate accordion to the refraction and/or diffraction principles stemming from their shape and composition.
Contact lens is a corrective, cosmetic, or therapeutic lens usually placed on and in contact with the cornea of the eye, hence the name contact lens. Contact lenses usually serve the same corrective purpose as eyeglasses, but are typically soft, lightweight and virtually invisible (some commercial lenses are tinted a faint blue to make them more visible when immersed in cleaning and storage solutions). Some cosmetic lenses are deliberately colored to alter the appearance of the eye. Some contact lenses have a thin surface treatment which is a UV-absorbing coating; this helps to reduce UV damage to the eye's natural lens. It has been estimated that 125 million people use contact lenses worldwide (2%).
Ophthalmic implants (also referred to herein as implantable ophthalmic devices), such as intraocular lenses, differ from contact lenses mainly by their permanent placement in the eye. Intraocular lenses (IOL), also known as implantable contact lenses, are special small corrective lenses surgically implanted in the eye's posterior chamber behind the iris and in front of the lens to correct higher degrees of myopia and hyperopia. When age or disease causes the lens to become less transparent, vision deteriorates because of the diminished light which can be transmitted to the retina. This deficiency in the lens of the eye is medically known as a cataract. An accepted treatment for this condition is surgical removal of the lens and replacement of the lens function by an intraocular lens. Implantable ophthalmic devices can be surgically implanted into a living cornea, or in other cases, are located in proximity to a damaged living cornea. It is highly desirable, even essential, for the long term viability of such corrective lens structure onlays or implants, that the material constituting these devices be chemically and physically stable and capable of sustaining and possible filtering damaging radiation. Typically, this material is a polymer or co-polymer of some sort.
Over the years, numerous types of IOLs have been developed for correcting vision deficiencies. Generally, such lenses operate accordion to one or two basic optical principles: refraction and diffraction.
A typical optical device is manufactured from a polymeric composition, has a diameter of about 5-7 mm, and is supported in the eye by the spring force of flexible loops called haptics.
Multifocal lens has more than one point of focus. A bifocal, which is a type of multifocal, has two points of focus, one at distance and the other at near. In multifocal IOL the aim is to increase the range of distinct vision and hence to reduce the dependence on additional spectacle corrections. Rigid lenses that have two or more optical powers are used to divide the incident light between axially separated images. Overall image quality is affected by the number of lens powers, and the image quality of the focused component itself.
One type of multifocal IOL is diffractive multifocal IOL. A pair of diffraction orders is used to provide two lens powers simultaneously by using rigid implant. One power is used for distance vision and the other power is used for near vision. In both cases defocused light is also incident on the retina, but the human visual system is tolerant of contrast-related image variations and this does not appear to be a problem for most patients. The diffractive design utilizes the full aperture and is tolerant of pupil size variations and modest decentration.
Generally, a diffractive lens consists of any number of annular lens zones of equal area. Between adjacent zones optical steps are provided with associated path length differences which usually are absolutely smaller than a design wavelength. The area or size of the zones determines the separation between the diffractive powers of the lens; this separation increases with decreasing zone area. The optical path difference determines the relative peak intensities of the various diffractive powers. For example, when the optical path difference equals half the wavelength there are two principal diffractive powers, the zeroth and the first order diffractive power. For absolute path differences which are smaller than half the wavelength, the zeroth order power is dominant, while for optical path differences which are of order of one wavelength the first diffractive order power is dominant.
Also known are lenses which are based on refractive principles. Such refractive lenses typically include concentric zones of differing power.
U.S. Pat. No. 4,338,005 discloses a multiple focal power optical device which includes a plurality of alternating annular concentric zones. At least some of the zones include focal power means for directing incident parallel light to a first focal point, and at least some of the zones include focal power means for directing incident parallel light to a second focal point. The radius of the nth zone is proportional to the square root of n, and the radius of the first zone is proportional to the square root of the wavelength under consideration.
U.S. Pat. No. 5,089,023 discloses an intraocular optical implant which includes a refractive/diffractive lens having an anterior surface and a posterior surface and a generally anterior-posterior optical axis. At least one of the anterior and posterior surfaces of the lens has a diffractive lens profile covering about half the effective lens area of the lens.
U.S. Pat. No. 5,699,142 discloses a diffractive multifocal ophthalmic lens having an apodization zone that gradually shifts the energy balance from the near focus to the distance focus over a substantial portion of the lens so that the outer region of the lens directs all of its energy to the distance focus.
U.S. Pat. No. 6,536,899 discloses a multifocal lens including a plurality of annular zones. Each annular zone is divided into two annular sub-zones such that the refractive powers within the sub-zones exhibit at least two diffractive powers and at least one of the diffractive powers substantially coincides with the average refractive power of each annular zone.
Additional background art includes U.S. Pat. Nos. 4,881,805, 5,344,47, 7,377,641, 4,162,122, 4,210391, 4,338,005, 4,340,283, 4,995,714, 4,995,715, 4,881,804, 4,881,805, 5,017,000, 5,054.905, 5,056,908, 5,120,120, 5,121,979, 5,121,980, 5,144,483, 5,117,306, 5,076,684, 5,116,111, 5,129,718, 4,637,697, 4,641,934 and 4,655,565, and European Patent No. 1194797B1.
In general, the material used for ophthalmic implants is required to be and to remain stable in prolong exposure to wear and UV light, and remain transparent and substantially glistening-free and vacuoles-free for extended periods of time at the physiological conditions of the eye, namely in contact with the eye's living tissue, tear enzymes and 37° C. A typical IOL is manufactured from polymethyl methacrylate, has a diameter of about 5-7 mm, and is supported in the eye by the spring force of flexible loops called haptics. Other materials are also used, and there are a variety of lens style and haptic designs.
Most contemporary contact optical devices, such as contact lenses and ophthalmic implants which are used for small incision cataract surgery, require foldable materials like hydrophilic and hydrophobic acrylics and silicones; however, hydrophilic acrylic/hydrogel suffers with incompatibly low refractive index (RI) and high posterior capsular opacification (PCO) rate. Other mechanical characteristics also contribute to this incompatibility, such as the springiness of silicon-based materials, which may result in corneal endothelium damage and/or rupture of capsular bag. Polymeric compositions such as hydrophobic acrylics are more desirable as these are typically characterized by higher RI allowing smaller incision cataract surgery, minimal chances of PCO and controlled elasticity.
Thus, ophthalmic devices made from polymeric compositions should be transparent, flexible, deformable, glistening-free, vacuoles-free, contaminant-free (leachables), have low tackiness, low internal reflections, characterized by low stress generation or local burning while machining, and other handling and manufacturing problems.
WO 1994/011764 teaches foldable intraocular lenses made from polymeric compositions of high refractive index, comprising a copolymer including a first constituent derived from a first monomeric component the homopolymers of which have a refractive index of at least about 1.50, a second constituent derived from a second monomeric component other than the first monomeric component the homopolymers of which have a glass transition temperature of less than about 30° C., a third constituent derived from a crosslinking monomeric component in an amount effective to facilitate returning a deformed intraocular lens made of these compositions to its original shape, and a fourth constituent as a hydrophilic monomer. However WO 1994/011764 is silent with respect to the superfluous unreacted monomer content which ultimately affects glistening property of the lens and amount of undesired leachable (extractable) impurities.
WO 1999/007756 discloses high refractive index copolymer compositions suitable for use in ophthalmic lenses, such as foldable intraocular lenses, consisting of conventional aromatic monomer and diacrylate oligomers such as epoxy acrylate, acrylated acrylics. WO 1999/007756 is silent with respect to several factors such as tackiness (stickiness, adhesiveness) of the resulting lenses resulting from monomers having a low Tg, internal reflection resulting from monomers having a high RI, and manufacturing process related internal stresses which results in non-linear heterogeneous mechanical/optical behavior of lenses.
U.S. Pat. No. 7,585,900 discloses soft, high refractive index, acrylic materials (polyethyl/methacrylate, PEA/PEMA) useful as intraocular lens materials, containing an aryl acrylic hydrophobic monomer as the single principal device-forming monomer and a tack-reducing macromer additive (diacrylated polydimethyl siloxane, PDMS). However, PDMS requires custom complex syntheses leading to higher production costs.
U.S. Pat. No. 5,331,073 discloses high refractive index polymeric compositions and foldable intraocular lenses made from such compositions. However, these acrylic-based polymeric compositions include fluorine-containing monomers to rectify tackiness, which are costly and present some biocompatibility issues.
U.S. Pat. No. 5,674,960 discloses PEA/PEMA-based high refractive index polymeric compositions, however, these compositions result in devices that suffer from internal reflection and persistent vacuoles in the ophthalmic implants made therefrom.
EP 1030194 discloses polymeric compositions for soft, transparent and flexible intraocular lens, based on combinations of aryl acrylate and hydrophilic monomer, wherein the content of the hydroxyalkyl acrylate monomer is at least 50%, rendering it too hydrophilic for compatible contact or implantable lenses.
U.S. Pat. No. 6,653,422 discloses soft, high refractive index, polymeric compositions for soft intraocular lenses, having an elongation of at least 150%, constituting of aromatic monomers such as 4-phenyl butyl acrylate, 3-benzyloxypropyl methacrylate in addition to PEA/PEMA.
U.S. Pat. No. 5,693,095 discloses polymeric compositions for foldable ophthalmic lenses, comprising hydrophilic and hydrophobic aromatic acrylic component.
U.S. Patent Application Publication No. 2008139769 discloses (meth)acrylate copolymer compositions for soft intraocular lenses, obtained by copolymerization of a monomer mixture containing aromatic acrylic hydrophilic components along with hydrophobic components.
WO 2004/029675 teaches the formation of intraocular lenses through a process of pre-gel formation and in fused silica mold and a process of casting and extraction.
U.S. Pat. No. 7,304,117 teaches diphenyl azo-based reactive yellow dyes and a process for preparing polymers using the same in the manufacturing of ophthalmic devices, such as intraocular lenses, having blue light absorption properties. Said polymers are capable of blocking blue light from reaching the retina of an eye implanted with the ophthalmic device, and thereby preventing potential damage to the retina.
U.S. Pat. No. 5,433,746 discloses polymer composition constituting aromatic monomers like PEA/PEMA and the likes.
Implantable ophthalmic devices must overcome such issues as cytotoxicity and biocompatibility, which may arise from leachable (extractible) contaminants, hence all ophthalmic devices should be free from leachable contaminants. To reduce these preexisting impurities, extraction steps are typically carried out. WO 2004/029675, U.S. Patent Application Publication Nos. 2005258096, 2004031275 and 2003116873 disclose such extraction methods; however, such batch extraction methods suffer from various process complexities and solvent issue.
U.S. Pat. No. 5,603,774 teaches reduction of the tackiness associated with certain such soft acrylic polymers useful for foldable intraocular lenses (IOLs), by plasma treatment of the polymer surface.
Additional background art includes U.S. Pat. Nos. 7,585,900, 5,693,095, 5,290,892, 5,403,901, 5,433,746, 5,674,960, 5,716,403, 5,861,031, 4,304,895 and 4,528,311, U.S. Patent Application Publication Nos. 2003130460, 2009132039, 2008269884, 2003130460, 2008139769, 2008021129, 2001014824, 2003116873 and 2005258096, WO 2001/018079, WO 2006/210438, WO 2006/187042, WO 1999/07756, WO 2009/137525, WO 2009/120511, WO 20008/011566, WO 2008/011564, WO 2001/018079, WO 2001/018078, WO 1999/007756, WO 2004/11764, WO 2004/029675, WO 2004/031275, WO 2009/104516, WO 2006/095750, WO 2009/025399, JP 2003119226, KR 20090047478, EP 1857477, CN101137684.
Light and oxygen induce degradation reactions in polymer-based devices that may not only modify them visually but also exert a detrimental influence on numerous mechanical, physical and optical properties. Such adverse effects can be minimized by use of light stabilizers which are chemical compounds able to interface with the physical and chemical process of light induced degradation.
Radiation reaching the surface of the earth is composed of direct sunlight and scattered light, and the ultraviolet (UV) part of the radiation spectrum is the part that is considered responsible for polymer degradation. The Environmental Protection Agency (EPA or USEPA) designates sub-ranges of ultraviolet light as UVA (315-400 nm), UVB (280-315 nm) and UVC (10-280 nm). UVC and partly UVB rays are absorbed in the oxygen and ozone containing layer located in stratosphere, therefore only part of UVB and UVA radiation reaches the surface of the earth, and constitutes the main factor in aging for polymer-based systems. However, thinning of ozone layer is shifting UV spectral composition towards shorter wavelengths. It is accepted that UV radiation in the range of 280-380 nm, which corresponds to 420-320 kJ, is responsible for polymer degradation. This energy is sufficient to break C—C, C—H, C—O, C—Cl, C—N covalent bonds, hence signifies the need of using light stabilizers in ophthalmic devices which are exposed to direct or indirect sun-light.
UV light is also damaging to living cells, and among these, cell that enable vision. Visible violet light contributes only 5% to scotopic vision (the monochromatic vision of the eye in dim light) but it is responsible for up to 14% UV blue phototoxicity (a phenomenon known in live-cell, where illuminating a fluorescent molecule or a fluorophore, causes the selective death of the cells that express this fluorophore). Ultraviolet radiation may also contribute to the development of ocular disorders such as cataract, ocular cancers, photokeratitis, macular degeneration and corneal degenerative changes (e.g. pterygium, droplet climatic keratopathy, pinguecula), retinitis pigmentosa, night blindness, cystoid macular oedema, solar retinopathy (damage to the eye's retina, particularly the macula, from prolonged exposure to solar radiation), ocular melanomas and like damages.
Photokeratitis (also known as welder's flash or arc eye) is an inflammation of the cornea caused by a brief exposure to UV radiation Like sunburn, it may be painful and may create symptoms including red eyes, a foreign body sensation or gritty feeling in the eyes, extreme sensitivity to light and excessive tearing. Scientific studies and research growing out of the U.S. space program have shown that exposure to small amounts of UV radiation over a period of many years may increase the chance of developing a cataract, and may cause damage to the retina, the nerve-rich lining of the eye that is used for seeing. Retina damage is usually not reversible, and cumulative damage of repeated exposure may contribute to chronic eye disease, as well as increase the risk of developing skin cancer around the eyelids. Long-term exposure to UV light is also a risk factor in the development of pterygium (a growth that invades the corner of the eyes) and pinguecula (a yellowish, slightly raised lesion that forms on the surface tissue of the white part of the eye).
Ultraviolet light (higher energy with respect to visible light) can be damaging to the light receptor cells. With a few exceptions (e.g., snakes, placental mammals), most organisms avoid these effects by having absorbent oil droplets around their cone cells. The alternative, developed by organisms that had lost these oil droplets in the course of evolution, is to make the lens impervious to UV light, precluding the possibility of UV light being detected, as it does not reach the retina. In the human and other animal eye, UV light is absorbed by molecules known as chromophores, which are present in the eye cells and tissues. Chromophores absorb light energy from the various wavelengths at different rates; a pattern known as absorption spectrum. Furthermore, natural chromophores found in the eye block UV light by fluorescence.
Transparent polymer-based ophthalmic devices are most sensitive to UV light, including visible violet light (400-440 nm). Most of the ophthalmic device research and manufacturing companies incorporate synthetic UV-blockers/absorbers (also referred to herein as light stabilizing additives or light stabilizers) in their ophthalmic devices. The primary function of light stabilizers is to protect the substance from the long-term degradation effects from light, most frequently ultraviolet light. Different UV stabilizers are utilized depending upon the substrate, intended functional life, and sensitivity to UV degradation. UV stabilizers, such as hydroxyphenyl-benzotriazole, hydroxyphenyl-triazine and benzophenone-based light stabilizers, act by absorbing the UV radiation and preventing the formation of, or scavenging, free radicals. Depending upon substitution, the UV absorption spectrum is changed to match the application, while their concentrations typically range from 0.05% to 5% by weight of the polymer.
Unlike naturally occurring chromophores, synthetic dyes used as UV-blockers for incorporation in transparent polymer-based ophthalmic devices typically do not show any kind of fluorescence, hence are less effective in blocking UV radiation than naturally occurring UV-blockers. Furthermore, synthesis of organic UV-blockers/absorbers intended for incorporation into transparent polymer-based ophthalmic devices involves complex, multi-step and costly manufacturing process, which limits the choice of the polymer to great extent. In addition to their production limits, synthetic light stabilizing additives may lack biocompatibility to some extent, and as such may cause the development of hypersensitivity of the epithelium cell layers after prolonged contact therewith, and may cause impairment of scotopic vision.
Moreover, in the case of implantable ophthalmic devices, the thickness of a typical device is required to be kept at a minimum for the sake of smaller incisions. In addition, the concentration of any potentially harmful UV-blockers must be kept at the lowest. Thus, since there is a direct link between the UV-blocking effect and the amount of UV-blocker in the path of the light, UV-blockers are required to have a large cross-section for interaction with the incoming UV radiation. UV-blockers with a relatively low cross-section are less suitable for use in transparent polymer-based ophthalmic devices since they require a long light-path and/or a high concentration in the transparent polymer-based ophthalmic device in order to block UV effectively.
U.S. Pat. Nos. 5,234,990 and 5,578,676 teach compositions for forming anti-reflective layers for DUV microlithographic processes, which include polysulfone and polyurea polymers that possess inherent light absorbing properties at deep ultraviolet wavelengths. These compositions are applied to a substrate to form an anti-reflective coating, and thereafter a photoresist material that is compatible with the anti-reflective coating is applied. These polymers are said to include an additive such as 4,4,-bis(N,N-dimethylamino)benzophenone, 7-diethylamino-4-methylcoumarian, curcumin, 3-aminopropyltriethoxysilane or (3-glycidoxypropyl)trimethoxysilane. These polymers are also said to be opaque, hence are not suitable for use in ophthalmic devices.
U.S. Pat. No. 7,304,117 teaches novel azo-based reactive yellow dyes and a process for manufacturing polymers, using the same in the manufacturing of ophthalmic devices, such as intraocular lenses, having blue light absorption properties. Said polymers are capable of blocking blue light from reaching the retina of an eye implanted with the ophthalmic device, and thereby preventing potential damage to the retina.
U.S. Patent Application Publication No. 20070204412 teaches transparent silicone polymers and elastomers colored by curcumin and/or a derivative thereof.

SUMMARY OF THE INVENTION

According to an aspect of embodiments of the present invention, there is provided a multifocal ophthalmic device, the lens body of which includes a co-polymeric composition as presented herein.
According to an aspect of embodiments of the present invention, there is provided a multifocal ophthalmic device which includes a lens body being formed with a plurality of concentric annular zones separated by slanted steps, wherein the concentric zones effect both diffraction and refraction of incident light, while the steps are substantially devoid of any diffractive or refractive power; the lens body of the device includes a co-polymeric composition being derived from a pre-polymerization mixture of monomers which includes:
a first aromatic acrylate monomer, characterized as forming a first homopolymer having a refractive index that ranges from 1.50 to 1.53;
a second aromatic acrylate monomer, characterized as forming a second homopolymer having a Tg lower by a range of 2° C. to 30° C. than a Tg of the first homopolymer;
a third monomer, characterized as forming a third homopolymer having a Tg lower than 35° C.;
a fourth monomer, characterized as forming a fourth homopolymer which is capable of absorbing water to at least 20% of the total weight of the fourth homopolymer; and
a fifth monomer, being a crosslinking monomer,
wherein:
a concentration of the first aromatic acrylate monomer ranges from 50% to 60% of the total weight of the composition;
a concentration of the second aromatic acrylate monomer ranges from 15% to 20% of the total weight of the composition;
a concentration of the third monomer ranges from 10% to 15% of the total weight of the composition;
a concentration of the fourth monomer ranges from 5% to 10% of the total weight of the composition;
a concentration of the fifth monomer ranges from 2% to 5% of the total weight of the composition; and
the lens body of the device and/or the co-polymeric composition includes at least one curcuminoid compound incorporated therein or thereon.
In some embodiments, in the composition presented herein:
a concentration of the first aromatic acrylate monomer ranges from 52% to 59% of the total weight of the composition;
the concentration of the second aromatic acrylate monomer ranges from 15% to 19% of the total weight of the composition;
the concentration of the third monomer ranges from 11% to 15% of the total weight of the composition;
the concentration of the fourth monomer ranges from 7% to 9% of the total weight of the composition;
the concentration of the fifth monomer ranges from 2% to 3.5% of the total weight of the composition; and
In some embodiments, the first monomer is selected from the group consisting of 2-phenoxyethyl acrylate, 2-phenoxy ethyl methacrylate, 2-benzyloxy ethyl acrylate, 2-benzyloxy ethyl methacrylate, 2-cyclohexyloxy ethyl methacrylate, 2-cyclohexyloxyl ethyl acrylate and combinations thereof.
In some embodiments, the second monomer is selected from the group consisting of 2-phenylethyl acrylate, benzyl acrylate, cyclohexyl acrylate, 2-chlorophenyl acrylate, 4-methyl benzyl acrylate, 2,4,6-tribromophenyl acrylate, pentabromophenyl acrylate and any combinations thereof.
In some embodiments, the third monomer is selected from the group consisting of cellosolve methacrylate, methoxy ethyl acrylate, polyethylene glycol monomethacrylate, 1-dihydroxyperflurobutyl methacrylate, 2,5-dibromopropyl methacrylate, hexyl methacrylate, glycerol monomethacrylate, trifluroethyl methacrylate, butyl methacrylate, n-ocyl/isooctyl methacrylate, n-decyl/isodecyl methacrylate, ethyl methacrylate, ethylene triglycol methacrylate, butyl diglycol methacrylate, methoxy polyethylene glycol 350 methhacrylate, methoxy polyethylene glycol 500 methhacrylate, methoxy polyethylene glycol 1000 methhacrylate, methoxy polyethylene glycol 2000 methhacrylate. methoxy polyethylene glycol 5000 methhacrylate, polypropylene glycon methacrylate, ethoxytriglycol methacrylate, 2-ethoxyethoxy ethyl methacrylate, methoxy triethyleglycol methacrylate, phenoxy polyethylene glycol monomethacrylate and any combinations thereof.
In some embodiments, the forth monomer is selected from the group consisting of hydroxyl ethyl methacrylate, glycerol monomethacrylate, ethylene triglycol methacrylate, butyl diglycol methacrylate, methoxy polyethylene glycol 350 methhacrylate, methoxy polyethylene glycol 500 methhacrylate, methoxy polyethylene glycol 1000 methhacrylate, methoxy polyethylene glycol 2000 methhacrylate, methoxy polyethylene glycol 5000 methhacrylate, polypropylene glycon methacrylate, ethoxytriglycol methacrylate, methoxy triethyleglycol methacrylate, phenoxy polyethylene glycol monomethacrylate and any combinations thereof.
In some embodiments, the fifth monomer is selected from the group consisting of ethylene glycol dimethacrylate, 1,4-butane diol diacrylate, glycerol dimethacrylate, allyl methacrylate, 1,6 heaxane diol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexane diol dimethacrylate and any combinations thereof.
In some embodiments, the mixture further which includes a free radical polymerization initiator.
In some embodiments, the initiator is a low temperature dissociation initiator. In some embodiments, the initiator is selected from the group consisting of dicetyl peroxydicarbonate, tert-butyl peroxypivalate, diisobutyryl peroxide, dimyristyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxypivalate, tert-butyl peroxyneoheptanoate, di(2-neodecanoylperoxy-isopropyl)benzene, cumylperoxy-neodecanoate, 1,1,3,3-tetramethylbutylperoxy-neodecanoate, t-butylperoxy-neodecanoate, t-butylperoxy-neoheptanoate and any combinations thereof. In some embodiments, the composition presented herein further includes an ultraviolet absorbing compound.
In some embodiments, the ultraviolet absorbing compound is selected from the group consisting of a curcuminoid compound as presented herein, a benzophenone, 2-hydroxybenzophenone, 2-(2-hydroxyphenyl)benzotriazole, 2-acryloxyethoxy hydroxyl benzophenone, phenol-2-(5-chloro-2H-benozotriazol-2-yl)-6-(1,1-)dimethyl-4-methyl, 4-benzoyl-3-hydroxyphenyl-2-methacrylate, 2-[4-(2h-1,2,3-benzotriazol2-yl)-3-hydroxyphenoxy]ethyl-2-methacrylate and any combinations thereof.
In some embodiments, the mixture further which includes a curing agent.
In some embodiments, the curing agent is selected from the group consisting of a peroxy catalyst, an oxide catalyst, tert-butyl peroxy-2-ethylhexanoate, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and any combinations thereof.
In some embodiments, the composition presented herein further includes an additive selected from the group consisting of a dye, a yellow dye/blue light blocker, a coating material, a heparin coating agent, a photochromic coating agent, a light-stabilizer, a pharmaceutical agent, a cell receptor functional group, a protein group, a viscosity agent, a diluent and any combination thereof.
Dyes (or tints or colorants) can be added in order to impart the device, particularly an implantable device, the color of the natural lens of the subject to be treated with the device.
In some embodiments, the composition presented herein is having a visible light transmission of at least 97% of incident visible light.
In some embodiments, the composition presented herein is having a refractive index of at least 1.53.
In some embodiments, the composition presented herein is having loop pull force mechanical strength of at least 60 grams.
In some embodiments, the composition presented herein is characterized by a glass transition temperature not higher than 5° C.
In some embodiments, the composition presented herein is characterized by Shore A hardness that ranges from 77 to 80.
In some embodiments, the composition presented herein is having an unfolding time of less than 6 seconds.
In some embodiments, the composition presented herein is characterized by having essentially no internal reflections.
In some embodiments, the composition presented herein is characterized by having essentially no vacuoles and/or perceivable glistening.
In some embodiments, the composition presented herein is having a leachable content of less than 0.6%.
In some embodiments, the composition presented herein is being essentially tack free.
In some embodiments, the lens body of the device and/or the co-polymeric composition further includes at least one curcuminoid compound incorporated therein or thereon.
According to another aspect of embodiments of the present invention, there is provided a multifocal ophthalmic device as presented herein, the lens body of which includes a polymeric or co-polymeric composition and at least one curcuminoid compound incorporated in or on the polymeric or co-polymeric composition and/or the lens body.
In some embodiments, the polymeric or co-polymeric composition is derived from a pre-polymerization mixture of monomers which includes at least 50 weight percents acrylate monomers.
In some embodiments, the polymeric or co-polymeric composition is a co-polymeric composition being derived from a pre-polymerization mixture of monomers which includes:
a first aromatic acrylate monomer, characterized as forming a first homopolymer having a refractive index that ranges from 1.50 to 1.53;
a second aromatic acrylate monomer, characterized as forming a second homopolymer having a Tg lower by a range of 2° C. to 30° C. than a Tg of the first homopolymer;
a third monomer, characterized as forming a third homopolymer having a Tg lower than 35° C.;
a fourth monomer, characterized as forming a fourth homopolymer which is capable of absorbing water to at least 20% of the total weight of the fourth homopolymer; and
a fifth monomer, being a crosslinking monomer, as described herein.
According to another aspect of some embodiments of the present invention there is provided a multifocal ophthalmic device as presented herein, the lens body of which includes a co-polymeric composition being derived from a pre-polymerization mixture of monomers which includes:
a first aromatic acrylate monomer, characterized as forming a first homopolymer having a refractive index that ranges from 1.50 to 1.53;
a second aromatic acrylate monomer, characterized as forming a second homopolymer having a Tg lower by a range of 2° C. to 30° C. than a Tg of the first homopolymer;
a third monomer, characterized as forming a third homopolymer having a Tg lower than 35° C.;
a fourth monomer, characterized as forming a fourth homopolymer which is capable of absorbing water to at least 20% of the total weight of the fourth homopolymer; and
a fifth monomer, being a crosslinking monomer, as described herein, and at least one curcuminoid compound incorporated in or on the composition and/or the lens body.
In some embodiments, the concentration of the curcuminoid compound ranges from 0.0002 weight percentage to 1 weight percentage of the total weight of the composition.
In some embodiments, the concentration of the curcuminoid compound decreases by less than 0.0001 weight percentage when the composition is subjected to a solvent extraction.
In some embodiments, the composition presented herein is substantially transparent to light at a wavelength ranging from about 400 to about 800 nm.
In some embodiments, the composition presented herein is substantially opaque to light at a wavelength ranging from about 190 to about 440.
In some embodiments, the curcuminoid compound is selected from the group consisting of curcumin, bisdemethoxycurcumin and monodemethoxycurcumin.
In some embodiments, the composition presented herein is substantially transparent to light at a wavelength ranging from 400 to 800 nm.
In some embodiments, the composition presented herein is substantially opaque to an electromagnetic radiation at a wavelength ranging from 190 to 440.
In some embodiments, the curcuminoid compound is tetrahydroxycurcumin.
In some embodiments, each step of the steps in the device presented herein is characterized by a radius, a slope and a height, and wherein the slope and the height are at least non-increasing functions of the radius.
In some embodiments, the lens body has an aspheric profile.
In some embodiments, the aspheric profile is characterized by a conic constant in a range of from about −1.0 to about −3.0, inclusive.
In some embodiments, the plurality of concentric zones which includes at least 20 concentric zones.
According to some embodiments of the invention the lens body concentric zones comprises at most 30 concentric zones.
In some embodiments, each step of the steps has a width which is from about 0.17 microns to about 0.2 microns.
In some embodiments, the heights vary from about 1.83 micron at the center to about 0.09 micron at the edge.
In some embodiments, the slopes vary from about 84° at the center to about 25° at the edge.
In some embodiments, the overall effective refractive area of the lens body is less than 60% of the total effective area of the lens body.
In some embodiments, the lens body is made of biocompatible material.
In some embodiments, the biocompatible material is hydrophilic acrylic material.
In some embodiments, at least one zone of the plurality of zones has a diffraction pattern formed thereon, such that a diffractive power the zone gradually decreases thereacross.
In some embodiments, the refractive power is substantially uniform across the lens body.
In some embodiments, the zones are substantially equal in area.
In some embodiments, the zones and the steps transmit at least 80% of incident light.
In some embodiments, the lens body is foldable.
In some embodiments, the device presented herein further includes haptic means coupled to the lens body.
In some embodiments, the ophthalmic or ocular device is selected from the group consisting of the multifocal ophthalmic device presented herein, an intraocular lens (IOL), a contact lens, a keratoprosthesis, a phakic lens, an aphakic lens, a corneal ring, a capsular bag extension ring, a corneal inlay and a corneal onlay.
In some embodiments, the device presented herein is selected from the group consisting of a contact lens and an implantable ocular device.
In some embodiments, a device as presented herein is identified for use in the treatment of an optical distortion, a retinal detachment, an occlusion, proliferative retinopathy; proliferative vitreoretinopathy, diabetic retinopathy, a degenerative disease and an age-related macular degeneration.
In some embodiments, a device as presented herein is selected from the group consisting of an intraocular lens (IOL), a keratoprosthesis, a phakic lens, an aphakic lens, a corneal ring, a capsular bag extension ring, a corneal inlay and a corneal onlay.
According to another aspect of embodiments of the present invention, there is provided a process of manufacturing the multifocal ophthalmic device as presented herein, wherein the lens body comprises a polymeric or co-polymeric composition being derived from a pre-polymerization mixture of monomers, as described herein, the process comprising:
admixing the pre-polymerization mixture of monomers and a free radical polymerization initiator;
heating the pre-polymerization mixture to 40° C. while stirring until a viscosity reach 120 cps at 25° C.;
degassing the pre-polymerization mixture so as remove volatile residues;
admixing an additional amount of the initiator into the pre-polymerization mixture so as to obtain a reaction mixture;
admixing a curing agent into the reaction mixture;
casting the reaction mixture into a mold; and
exposing the reaction mixture to curing conditions, to thereby obtain the device,
wherein either the mold is shaped as an inverse form of the concentric annular zones prior to the exposing to curing conditions or the device is subjected, subsequent to the exposing to curing conditions, to polishing and machining so as to form the concentric annular zones.
In some embodiments, the process further comprises, subsequent to the exposing to curing, subjecting the device to a multiple extraction, as described herein.
In some embodiments, in the process presented herein, the free radical polymerization initiator is selected from the group consisting of dicetyl peroxydicarbonate, tert-butyl peroxypivalate, diisobutyryl peroxide, dimyristyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxypivalate, tert-butyl peroxyneoheptanoate, di(2-neodecanoylperoxy-isopropyl)benzene, cumylperoxy-neodecanoate, 1,1,3,3-tetramethylbutylperoxy-neodecanoate, t-butylperoxy-neodecanoate, t-butylperoxy-neoheptanoate and any combinations thereof.
In some embodiments, the process presented herein further includes, prior to the casting, filtering the reaction mixture.
In some embodiments, the curing agent is selected from the group consisting of a peroxy catalyst, an oxide catalyst, tert-butyl peroxy-2-ethylhexanoate, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and any combinations thereof.
In some embodiments, the process presented herein further includes, subsequent to the curing, exposing the composition to a treatment selected from the group consisting of a plasma treatment, a surface fluorination, a bulk fluorination, a hydrophilic coating, an electron beam irradiation, a high energy UV irradiation, a energy intensive irradiation, a internal wetting agent and any combination thereof.
In some embodiments, the multiple extraction which includes releasing the co-polymeric composition from the mold; and sequentially immersing the co-polymeric composition in a series of solvent baths to thereby extract unreacted contaminants.
In some embodiments, the machining to form the concentric annular zones is effected by a computerized numeric controlled lathe.
Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The patent or application file contains at least one drawing executed in color. Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings and images. With specific reference now to the drawings and images in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings and images makes apparent to those skilled in the art how embodiments of the invention may be practiced.

In the drawings:

FIGS. 1A-1B are schematic illustrations of a top view (FIG. 1A) and a profile view (FIG. 1B) of a multifocal ophthalmic device 10, according to various exemplary embodiments of the present invention;

FIG. 2A is a schematic illustration of a single zone and slanted step of a conventional lens body;

FIG. 2B is a schematic illustration of a single zone and slanted step of a lens body according to various exemplary embodiments of the present invention;

FIG. 3 is a schematic illustration of geometrical definition of a zone and a step adjacent thereto, according to various exemplary embodiments of the present invention;

FIG. 4 is a schematic illustration of an aspheric lens body, according to various exemplary embodiments of the present invention;

FIGS. 5A-5B are schematic illustration of an outermost zone (FIG. 5A) and an innermost zone (FIG. 5B) of a prototype ophthalmic device designed according to various exemplary embodiments of the present invention.

FIG. 6 is a UV-Vis absorption spectra of a sample of curcumin after purification on a preparative silica gel column at 25° C., using a mixture of chloroform and ethyl acetate (9:1 ratio);

FIGS. 7A-7B are UV/Vis transmission and absorption spectra as measured from slice samples of a rod-shaped object prepared from a curcumin/POEMA/CHMA/BDDA polymerization mixture, an exemplary composition according to some embodiments of the present invention, after mild washing and drying (FIG. 7A) and after Soxhlet extraction for 3 hours in toluene (FIG. 7B);

FIGS. 8A-8D are UV/Vis transmission and absorption spectra, as measured after Soxhlet extraction and drying, obtained from transparent slices having curcumin at a final content of 0.005 weight percents (FIG. 8A), PDPMA at a final content of 0.005 weight percents (FIG. 8B), curcumin at a final content of 0.025 weight percents (FIG. 8C), and PDPMA at a final content of 0.025 weight percents (FIG. 8D); and

FIGS. 9A-9D are UV/Vis absorption spectra, as collected from lens prepared with curcumin at 0.025 weight percentage, before extraction (FIG. 9A), from the same lens after extraction (FIG. 9B), from lens prepared with curcumin at 0.05 weight percentage, before extraction (FIG. 9C), and from the latter lens after extraction (FIG. 9D).

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

The present invention, in some embodiments thereof, relates to ophthalmic and ocular devices, and more particularly, but not exclusively, to multifocal ophthalmic devices made of polymeric or co-polymeric compositions.
The principles and operation of some embodiments of the present invention may be better understood with reference to the figures and accompanying descriptions.
Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details set forth in the following description or exemplified by the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.
Shape and composition of optical devices determine their interaction with light. While the shape of an optical device such as a lens mainly controls refractive and diffractive aspects, the composition mainly controls refractive and reflective aspects. Light transmissive polymeric materials have been used for decades to construct optical devices as corrective measures for refractive errors and other conditions of failing eye sight and vision. Such materials have been found suitable for lenses due to the ease of forming various complex and precise shapes therefrom, using casting, molding, machining, polishing and various combinations of these industrial techniques, and due to the relative chemical stability of such polymeric compositions under various conditions.
Yet, presently known polymeric compositions used in the manufacturing of ophthalmic and ocular devices, and particularly such implantable devices, suffer from a variety of shortcomings, which include, for example, bio-incompatibility, leachable contaminants, degradation in physiological conditions, UV vulnerability, incompatible refractive index, internal reflections, tackiness, glistening, vacuoles, high cost of materials and manufacturing complexities.
The present inventors have sought a comprehensive solution to a group of problems associated with ophthalmic and ocular devices made from polymeric compositions, including corrective measures requiring multifocal capabilities, and clear, biocompatible and UV-light stabilized materials.
As used herein, the phrase “ophthalmic and ocular device”, refers to devices that reside in or on the eye. These devices can provide optical correction, wound care, drug delivery, diagnostic functionality, cosmetic enhancement or effect or a combination of these properties. The phrase “ophthalmic and ocular device” includes but is not limited to lenses in general, multifocal lens devices, soft contact lenses, hard contact lenses, intraocular lenses (IOLs), keratoprostheses, phakic and aphakic lenses, corneal overlay and inlay lenses, ocular inserts, corneal rings, capsular bag extension rings, and optical inserts.
The present inventors contemplated exploiting the refraction phenomena of a unique co-polymeric composition for devising a polymeric-based multifocal ophthalmic device. The present inventors further contemplated that curcuminoid compounds can be used for devising a UV-stabilized polymeric-based multifocal ophthalmic device.
A Multifocal Ophthalmic Device:
According to an aspect of some embodiments of the present invention, there is provided a multifocal ophthalmic device which includes a lens body which is formed with a plurality of concentric annular zones separated by slanted steps, wherein the concentric zones effect both diffraction and refraction of incident light, while the steps are substantially devoid of any optical power, specifically devoid of diffractive power and/or refractive power. In some embodiments of the present invention the steps are substantially devoid of diffractive power and refractive power.
As used herein, “optical power” refers to the ability of at least a portion of an optic surface to redirect incident light for the purpose of forming a real or virtual focus or focal point on a plane known as the focal plane. The optical power may result from refraction, diffraction, or some combination thereof. The optical power of a surface or part of a surface is generally equal to the reciprocal of the distance between the surface and the focal plane. This distance is also known as “the focal distance” of the surface. When the fical distance is expressed in meters, the optical power is expressed in diopters wherein 1 diopter equals 1 m⁻¹.
As used herein, “refractive power” refers to optical power produced by the refraction of light as it interacts with an optical device or part thereof.
As used herein, “diffractive power” refers to optical power resulting from the diffraction of light as it interacts with an optical device or part thereof.
In some embodiments, the lens body of the device is made of a co-polymeric composition which includes a polymeric backbone composed of a plurality of backbone units covalently linked to one another, which is derived from a pre-polymerization mixture of monomers having a unique formulations as presented hereinbelow. In some embodiments, the lens body of the device is made of a polymeric or co-polymeric composition and further includes at least one curcuminoid compound, as presented hereinbelow, incorporated in the polymeric or co-polymeric composition or on the lens body as a mean to provide UV-light stabilization. In some embodiments, the lens body of the device is made of a co-polymeric composition as described hereinabove, which further includes at least one curcuminoid compound, as presented hereinbelow, incorporated in or on the co-polymeric composition and/or the lens body.
Typically, the ophthalmic device according to some embodiments of the present invention, has diffractive power for enabling near vision and refractive power for enabling far vision. In various exemplary embodiments of the invention the ophthalmic device also enable intermediate vision, as further detailed hereinunder.
The term “near vision,” as used herein, refers to vision provided by at least a portion of an optical device, such as a multifocal ophthalmic device according to some embodiments of the invention, wherein objects relatively close to the subject are substantially in focus on the retina of the eye of a subject. The term “near vision” generally corresponds to vision provided when objects are at a distance between about 25 cm to about 50 cm.
The term “distant vision” or interchangeably “far vision,” as used herein, refers to vision provided by at least a portion of an optical device, such as a multifocal ophthalmic device according to some embodiments of the invention, wherein objects relatively far from the subject are substantially on the retina of the eye. The terms “distant vision” and “far vision” generally correspond to vision provided when objects are at a distance of at least about 1 meter to about 2 meters away from the subject, preferably at a distance of 5 to 6 meters or greater.
The term “intermediate vision” as used herein generally refers to vision provided by at least a portion of an optical device, such as a multifocal ophthalmic device according to some embodiments of the invention, wherein objects at an intermediate distance from the subject are substantially in focus on the retina of the eye. Intermediate vision generally corresponds to vision provided when objects are at a distance of from about 40 centimeters to about 1.5 meters.
Referring now to the drawings, FIGS. 1A-B illustrate a top view (FIG. 1A) and a profile view (FIG. 1B) of a multifocal ophthalmic device 10, according to various exemplary embodiments of the present invention. Device 10 comprises a lens body 12 being formed with a plurality of concentric annular zones 14 separated by slanted steps 16 (shown better in FIG. 1B). The number of concentric zones is preferably at least 20, or at least 22 or at least 24 or at least 26 or at least 28, or at least 29. The number of concentric zones is preferably at most 30. In some embodiments of the present invention device 10 comprises 30 zones.
Device 10 can be used in more than one application. In some embodiments the device is implemented as intraocular lens device, in which case the lens body is constituted as an ophthalmic intraocular lens. In some embodiments the device is implemented as a contact lens, in which case the lens body is constituted as a contact lens, and in some embodiments the device is implemented as a spectacle lens in which case lens body is constituted as a spectacle lens.
In any of the above embodiments, lens body 12 preferably has an aspheric profile. Generally, the aspheric profile can be characterized by a conic constant in a range of from about −1.0 to about −3.0, inclusive.
A representative example of an aspheric lens body is illustrated in FIG. 4.
Typically, the lens body is made of a polymeric or co-polymeric material which is sufficiently transparent to visible light and which is suitable for optics. The material used for making the lens body, according to some embodiments of the invention, is discussed in further detail hereinunder.
The term “transparent”, used herein in the optical sense, describes the physical property of a substance to allow light to pass (transmit) therethrough. The term “transparent” is used herein as the opposite to the term “opaque”, and it is not used to refer to translucency or translucidity (partial transparency). Hence, according to some embodiments of the present invention, a transparent substance is clear, and exhibits pellucidity or diaphaneity. The term transparent does not necessarily refer to other manifestations of light-matter interactions such as diffraction, refraction or dispersion. Accordingly, the term “opaque”, used herein in the optical sense, describes the physical property of a substance to block light from passing (transmitting) therethrough.
The properties of transparency and opacity may be wavelength dependent, meaning that the same substance may be transparent with respect to light of a certain range of wavelengths, while at the same time be opaque with respect to light of another range of wavelengths, hence acting like a wavelength-selective filter of light. In the context of the present embodiments, a substantially transparent composition allows at least 98% of the light intensity of a given range of wavelength to pass therethrough (a maximal loss of 2% of the light's intensity), while a substantially opaque composition reflects, scatters or absorbs more than 98% of the incoming light of a given range of wavelength, allowing less than 2% of the light to pass therethrough. Alternatively, transparency is defined as transmission of 95% of the light intensity of a given range of wavelength.
Visible light, as defined by the visibility of a typical human eye, is characterized by a wavelength ranging from 390 nm to 750 nm. According to some embodiments of the present invention, the composition for making the ophthalmic devices presented herein is characterized by being substantially transmissive (transparent) to visible light.
In various exemplary embodiments of the invention the lens body is foldable and reshapable, as these terms are described and parameterized hereinbelow. These embodiments are particularly useful when device 10 is used as an intraocular lens device or a contact lens device.
The device of the present embodiments differs from conventional lens devices in that substantially the entire contributions to the diffraction and refraction powers are in zones 14, whereas the contribution of steps 16 to diffraction and refraction powers is negligible or zero, even though they are slanted with respect to the optical 18 and transverse 20 axes of lens body 12. Thus, in various exemplary embodiments of the invention concentric zones 14 effect both diffraction and refraction of incident light, while the slanted surfaces of steps 16 are substantially devoid of any diffractive or refractive power.
This advantage is illustrated in FIGS. 2A-B, which illustrate a single zone 24 and slanted step 26 of a conventional lens body (FIG. 2A) and a single zone 14 and slanted step 16 of lens body 12 (FIG. 2B). In FIGS. 2A-B, R1 and R2 represent refractive powers which generally equal the zeroth diffractive power, D1 represents the first order diffractive power and R0 represents a zero refractive power. In the conventional lens body, both the zones 24 and slanted steps 26 have optical power: step 26 has only a refractive power (R1) and zone 24 has both refractive (R2) and diffractive (D1) powers. In lens body 12, on the other hand, step 16 is substantially devoid of any optical (refractive or diffractive) power.
It is appreciated that whether or not there is optical power depends on the accuracy of the device which measures the optical power. As used herein, “substantially devoid of optical power” refers to zero optical power or optical power which is below 0.5 diopters, more preferably below 0.4 diopters more preferably below 0.3 diopters more preferably below 0.2 more preferably below 0.1 diopters.
Thus, every portion of lens body 12 has optical power (diffractive and/or refractive), but the contribution of this optical power generally comes from the zones and not the steps. The optical power of the zones is achieved by providing the zones with a finite radius of curvature relative to the transverse plane containing transverse axis 20 and/or with a secondary diffraction patterns 21 on their surface. However, the steps are preferably made planar, namely with infinite or very large radius of curvature.
The terms “refractive power” and “diffractive power” as used herein with respect to a particular optical element (either a section of lens body 12 or lens body 12 as a whole), refer to the dominant optical power of that element. Specifically, a particular optical element is said to have a refractive power if at this element the refractive power dominates the diffractive power, and particular optical element is said to have a diffractive power if at this element the diffractive power dominates the refractive power. If the refractive and diffractive powers are comparable, the element is said to have both optical powers.
In some embodiments of the present invention the diffractive power of the zones gradually decreases across each zone in the radial direction r (throughout this specification, underlined italic symbols represent vectors). This is illustrated in FIG. 2B for the case in which the diffractive power of the zone is the first order diffractive power. The advantage of gradually decreasing diffractive power is that it provides intermediate vision along with near and distance vision. Gradual decrease of the diffractive power across each zone can be achieved by changing the diffraction pattern across the zone. The gradually decreasing diffractive power is optionally and preferably at surfaces of the zones between successive steps.
The refractive power of device 10 is preferably substantially uniform across lens body 12. For example, in some embodiments of the present invention, each zone can have the same refractive power, with deviations of less that 10% or less than 5%. Additionally, the refractive power of the zone can be substantially uniform across the refractive section of this zone. The overall effective refractive area of lens body 12 is preferably small. In some embodiments of the present invention overall effective refractive area is less than 80% or less than 70% or less than 60% of the total effective area of lens body.
FIG. 3 illustrates the geometrical definition of a zone 14 and a step 16 adjacent thereto. For clarity of presentation, FIG. 3 does not illustrate the entire lens body 12, however, the center of lens body 12 is shown at 30 for reference.
Step 16 is characterized by a radius ρ_s(measured, e.g., from the center 30 of lens body 12 to the center of the step along radial direction r), a slope s (measured, e.g., relative to the transverse plane containing transverse axis 20), a height H (measured, e.g., from the base 28 of lens body 12 to the tip 32 of the step), and a width W_s(measured, e.g., from tip 32 to the end 34 of the previous zone along radial direction r).
Zone 14 is characterized by a radius ρ_z(measured, e.g., from the center 30 of lens body 12 to the center of the zone along radial direction r), a width W_z(measured, e.g., from tip 32 to the beginning 38 of the next step along radial direction r) and a curvature (not shown in FIG. 8). The height H of step 16 also characterizes zone 14.
In some embodiments of the present invention the slope s and height H of a particular slanted step 16 are at least non-increasing functions of the radius ρ_s. For example, the slope and height can be decreasing functions of the radius. In other words, in this embodiment, the steps are ordered such that their slopes and heights are decreasing from center to edge. As a representative example for height decrease, the heights can vary from about 1.83 micron at the center of the lens body (where the radius ρ_sis the smallest) to about 0.09 micron at the edge of the lens body (where ρ_sis the largest). As a representative example for slope decrease, the slopes can vary from about 84° at center to about 25° at edge.
The decreasing functions of the radius of the radius can be expressed analytically. However, from a practical point of view these functions can be expressed as lookup tables. A representative example of such lookup table, for a lens body having of 30 zones and 30 steps is provided in the Example section that follows (see Table 1).
In some embodiments of the present invention steps 16 have generally the same width W_s, with about 10% or less deviation. Representative examples for width W of step 16 suitable for the present embodiments includes width ranging from about 0.17 microns to about 0.2 microns, or from about 0.18 microns to about 0.19 microns, inclusive. In some embodiments of the present invention all steps have widths which are either 0.18 microns or 0.19 microns.
Preferably, the zones 14 of lens body 12 are substantially equal in area, with deviation of less than 10% or less than 5%. This embodiment is advantageous since it reduces or eliminates halos and glare.
In some embodiments of the present invention device 10 further comprises haptic means 36 coupled to lens body 12 (see FIG. 1A). These embodiments are particularly useful when device 10 is used as an intraocular lens device, in which case haptic means 36 can be used for placing and optionally anchoring device 10 into the eye of the subject.
The lens body of the present embodiments provides high level of light transmission. In various exemplary embodiments of the invention the zones and steps transmit at least 75%, or at least 76%, or at least 77%, or at least 78%, or at least 79%, or at least 80% of incident light.
The use of zones and steps according to various exemplary embodiments of the present invention is particularly useful from the stand point of manufacturing process. Since the steps are substantially planer, the machining of the lens is substantially simpler compared to conventional lenses.
Additional advantages of the ophthalmic device of the present embodiments over conventional vision correcting lenses include, without limitation, reduced or no aberration to the optical system, reduced or no halos and light scattering, tolerated decentration and combination of intermediate vision with far and near vision. Further, when the device is used as an intraocular lens device or contact lens device, its aspheric shape fits the surface of cornea hence making the device suitable for many patients.
The present embodiments also contemplate a method of treating medical, ophthalmologic and/or esthetic conditions associated with the eye, including correction of vision of a subject in need thereof, by using any of ophthalmic devices described herein. The method may be carried out by implanting the multifocal ophthalmic device in an eye of the subject, thereby treating the aforementioned conditions of the subject. The multifocal ophthalmic device can be, for example, device 10 as further detailed hereinabove. The method can be exercised, for example, while or subsequently to a cataract surgery. The devices disclosed herein can be beneficially used to correct standard optical distortions and in the treatment of ophthalmic conditions, such as for example, retinal detachment; occlusions; proliferative retinopathy; proliferative vitreoretinopathy; diabetic retinopathy; inflammations such as uveitis, choroiditis, and retinitis; degenerative disease (such as age-related macular degeneration, also referred to as AMD); vascular diseases; and various tumors including neoplasms.
Hence, according to some embodiments of the present invention, the device presented herein is identified as an implantable or externally applied medical device for use in the treatment of an optical distortion (optical corrective treatment), retinopathy, a retinal detachment, an occlusion, proliferative retinopathy; proliferative vitreoretinopathy, diabetic retinopathy, a degenerative disease and an age-related macular degeneration.
The devices may take the form of a contact lens, an implantable ophthalmic device, an intraocular lens (IOL), a keratoprosthesis, a phakic lens, an aphakic lens, a corneal ring, a capsular bag extension ring, a corneal inlay and a corneal onlay.
Compositions for Making a Multifocal Ophthalmic Device:
In general, ophthalmic and ocular devices differ from spectacles (eye-glasses) and other optical devices, by being designed to be in direct contact with the living tissue of the eye or its immediate surroundings. The devices which come in such direct contact are required to be biocompatible, as discussed herein, as well as to have certain physical properties with respect to their mechanical reshapability and reformability, flexibility, water-absorption capacity, and the likes. Implantable devices differ from non-implantable devices mainly by their mode of use and administration as well as their term of use, namely the devices that require a surgical procedure in order to be put in place are typically referred to as implantable. Implantable ophthalmic and ocular devices are expected to last longer and thus the requirements for their stability and compatibility in all aspects are much higher.
In principle, the multifocal ophthalmic device can be prepared from any polymeric or co-polymeric composition which is formulated to confer the required and desired chemical and mechanical attributes, as discussed herein.
A composition used in ophthalmic applications is typically formulated to be bio-compatible, chemo-compatible and physico-compatible so as to be adequate for use within the above-described ophthalmic device, or any other ophthalmic and ocular devices.
The term “bio-compatible”, as used in reference to polymeric or co-polymeric compositions as presented herein, refers to the non-toxic and benign effect that the composition has on a living tissue (e.g., an eye or a portion or a component thereof) when in contact therewith.
The term “chemo-compatible”, as used in reference to polymeric or co-polymeric compositions as presented herein, refers to the long-term non-leachability of unreacted components and diluents, non-degradability and overall long-term chemical stability of the composition when in contact with a living tissue in the eye and exposed to ambient light.
The term “physico-compatible”, as used in reference to polymeric or co-polymeric compositions as presented herein, refers to the optical properties of the compositions in terms of refractive index, internal reflections, light transmission and/or absorbance, and other properties relating to light-matter interaction.
The present inventors have contemplated a formation of a multifocal device as described herein from polymeric and co-polymeric compositions designed suitable for use in such a device.
The polymeric or co-polymeric compositions presented herein, are typically derived from a mixture of monomers. In polymeric compositions, the monomers in the mixture are the same whereby in co-polymeric compositions several different classes of monomers are used As in any polymer, the polymeric or co-polymeric composition is based on plurality of polymeric backbones, each of which consists of a plurality of backbone units which are covalently attached to one another, and each of the backbone units comprises a plurality of building-blocks or polymerized monomeric units. Hence, the a polymeric or co-polymeric composition as presented herein, which is the outcome of polymerizing a pre-polymerization mixture of monomers, can be characterized and defined at the chemical and physical property level, in terms of the pre-polymeric mixture, namely its constituents prior to polymerization.
The monomers which are put into the pre-polymerization mixture are still unreacted (not yet polymerized) and are regarded as the starting materials for the compositions presented herein. In the case of a co-polymeric composition as presented herein, each of the monomers, identified and classified into classes, can be characterized by chemical and physical properties exhibited by the corresponding homopolymer which is derived from each of the individual monomer in the class. Hence, the co-polymeric compositions presented herein can be characterized by the monomer class which it is derived from, as well as the relative amount-ratios between each monomer class in the pre-polymerization mixture.
As used herein, the term “monomer” is used to describe a constituent of the pre-polymerization mixture which affords, upon polymerization, the polymeric or co-polymeric compositions presented herein. It is noted herein that while some of the constituents of the pre-polymerization mixture participate in the polymerization process as reactants which form covalent bonds with other constituents in the mixture during the polymerization process, some may not react with other constituents in a covalent-bond-forming reaction, but become embedded or incorporated within the matrix of the polymeric or co-polymeric composition, as will be discussed hereinbelow.
According to some embodiments of the present invention, a pre-polymerization mixture as described herein may include any of the monomers as described herein, as a starting material, in its monomeric form, or, alternatively, as a polymeric building block, which typically has a relatively low average molecular weight of about less than 2000 Daltons (as measured via gel permeation chromatography refractive index detection). According to other embodiments of the present invention, the starting material can include dimmers of a monomer (two monomeric units or building blocks) and in some cases be a short oligomer of building blocks, including oligomers made from more than one type of monomeric unit. Short oligomers are commonly referred to in the art as “blocks”.
Some of the above-described embodiments therefore relate to a multifocal ophthalmic device which includes a lens body which is formed with a plurality of concentric annular zones separated by slanted steps, wherein the concentric zones effect both diffraction and refraction of incident light, while the steps are substantially devoid of any diffractive or refractive power, as described herein, and wherein the lens body is made of a polymeric or co-polymeric composition which includes a polymeric backbone composed of a plurality of backbone units covalently linked to one another, which is derived from a pre-polymerization mixture of monomers having an improved formulations as presented hereinbelow. Optionally, according to some embodiments, the polymeric or co-polymeric composition includes at least one curcuminoid compound, as presented hereinbelow, incorporated in the composition or on the lens body as a mean to provide UV-light stabilization.
Hydrophobic Co polymeric Composition for Making a Multifocal Ophthalmic Device:
According to some embodiments of the present invention, the lens body of the multifocal ophthalmic device presented herein is made of a co-polymeric composition which is uniquely designed suitable for ophthalmic devices. As discussed hereinabove, these co-polymeric compositions presented herein are formulated to be bio-compatible, chemo-compatible and physico-compatible.
Hence, according to an aspect of some embodiments of the present invention, there is provided a multifocal ophthalmic device, as described herein, wherein the lens body of the device comprises a co-polymeric composition which is suitable for use in ophthalmic applications.
In some embodiments, the co-polymeric composition is based on five matrix-forming constituents (monomers) as well as other ingredients such as catalyst, UV-stabilizer/blocker and high energy visible blue light stabilizer. The compositions may further comprise colorant/dye additives, leachable agents (drugs) and the likes.
It is noted that the co-polymeric composition of the present embodiments is compatible for use in the eyes and is optically clear and suitable for use as material of construction of ophthalmic and ocular device. By optically clear it is meant that the composition is essentially transparent to visible light, as described and defined herein.
The co-polymeric composition presented herein typically and advantageously exhibits relatively high refractive indexes when in its final form and fully hydrated. The refractive index of the final and fully hydrated co-polymeric composition presented herein, is typically greater than about 1.5, more typically greater than about 1.51, still more typically greater than about 1.52 and even possibly greater than 1.53 or even 1.54, wherein the refractive index of the fully hydrated composition is measured at 25° C. in accordance with ASTM D 542-00 (2006).
Hence, according some embodiments of the present invention, the lens body of the multifocal ophthalmic device presented herein comprises a co-polymeric composition, the composition being derived from a mixture of monomers that includes:
a first aromatic acrylate (aryl acrylate) monomer characterized as forming, upon polymerization thereof, a first homopolymer which exhibits a refractive index that ranges from 1.50 to 1.53;
a second aromatic acrylate (aryl acrylate) monomer characterized as forming, upon polymerization thereof, a second homopolymer, which exhibits a Tg (glass transition temperature) lower than the Tg of the homopolymer derived from the first monomer by a range of 2 to 30 degrees centigrade;
a third monomer characterized as forming, upon polymerization thereof, a third homopolymer, which exhibit a Tg lower than 35° C. or lower than 37° C.;
a fourth monomer characterized as forming, upon polymerization thereof, a fourth homopolymer, which exhibit a capacity to absorb water to at least 20% of its dry weight; and
a fifth monomer serving a crosslinking agent.
According to some embodiments of the invention, a concentration of the first aromatic acrylate monomer ranges from 50% to 60% of the total weight of the composition;
a concentration of the second aromatic acrylate monomer ranges from 15% to 20% of the total weight of the composition;
a concentration of the third monomer ranges from 10% to 15% of the total weight of the composition;
a concentration of the fourth monomer ranges from 5% to 10% of the total weight of the composition; and
a concentration of the fifth monomer ranges from 2% to 5% of the total weight of the composition.
It is noted that the co-polymeric compositions presented herein, which are formed from a number of monomer classes, referred to herein as a first, second, third, fourth and fifth monomers, can include a variety of different monomers of each class, namely one or any number of monomers mentioned within the class of monomers corresponding to the first, second, third, fourth or fifth monomer.
Unless otherwise stated, the percentages (e.g., weight percentages) of the constituents of the co-polymeric composition presented herein are denoted as weight percentages of the starting material with respect to the total weight of the pre-polymerizable mixture.
According to some embodiments of the present invention, the co-polymeric composition presented herein contains less than 75% in total of aryl acrylate monomers, keeping the major component of the co-polymeric composition based on aryl acrylate, as opposed to a mixture of aryl methacrylate and aryl acrylate known in the art, which is less suitable for ophthalmic applications in general and for the multifocal ophthalmic device presented herein.
One disadvantage of using aryl acrylate and aryl methacrylate/acrylate in more than 80% concentration is the occurrence of internal reflections and glare which may appear in a multifocal ophthalmic device made from such co-polymeric composition. This disadvantage is mitigated by controlling the content of the aryl (aromatic) monomer in the composition.
In general, every monomer adds from its associated property to co-polymeric composition, and when all property adds up in a prerequisite proportion, they form a co-polymer suiting the application.
The fifth monomer (class) is a crosslinking agent, as defined hereinbelow, interchangeably referred to herein as a crosslinker, which is characterized according to its capacity to alter the strength, rigidity and consistency of the co-polymeric composition presented herein. Thus, the crosslinking monomer (the fifth monomer) is a component having an effect on controlling flexibility of the obtained material for a soft embodiment of composition presented herein, giving the desired mechanical strength, improving capability of deformation recovery, and increasing co-polymerizable property with components for polymerization. Co-polymeric compositions which are not cross-linked may deteriorate rapidly as polymer chains are loosely held and increasing the possibility of getting extracted out under soxhlation extraction (gel content), resulting into loss of strength, loss of shape recovery and higher occurrence of vacuoles. The crosslinker is also the constituent that leads to an increase in the molecular weight of the composition (size of an average contiguous chain) by tethering chains to one-another. The molecular weight of the composition has a direct effect on the glistening, mechanical properties, refractive index and many other mechanical and optical properties of the composition and subsequently a device made therefrom
The first monomer (class) is an aromatic (aryl-containing) acrylate type monomer (hence, a first aromatic monomer) which is characterized as forming, upon polymerization thereof, a first homopolymer having a refractive index between 1.50-1.53 (a criterion for selecting the first monomer). As a constituent of the co-polymeric compositions presented herein, the first monomer can include one or more monomer structures, namely different monomers wherein each satisfies at least the aforementioned criterion.
Acrylate monomers constitute a family which is a type of vinyl monomers, or esters which contain a vinyl group, namely two carbon atoms double-bonded to each other, directly attached to the carbonyl carbon of a carboxyl group, as illustrated in Scheme 1 below.
The term “methacrylate” refers to an acrylate monomer having a methyl group at position R₂in Scheme 1 above.
The phrase “aromatic acrylate”, as used herein, refers to an acrylate ester having an aromatic substituent attached to the carbonyl, denoted R₄in Scheme 1 above. Accordingly, the phrase “aromatic methacrylate” refers to a monomer as illustrated in Scheme 1 above, wherein R₂is a methyl group and R₄is an aryl or a heteroaryl group.
An “aryl” group refers to an all-carbon monocyclic or fused-ring polycyclic (i.e., rings which share adjacent pairs of carbon atoms) groups having a completely conjugated pi-electron system. Examples, without limitation, of aryl groups are phenyl, naphthalenyl and anthracenyl. The aryl group may be substituted or unsubstituted.
A “heteroaryl” group refers to a monocyclic or fused ring (i.e., rings which share an adjacent pair of atoms) group having in the ring(s) one or more atoms, such as, for example, nitrogen, oxygen and sulfur and, in addition, having a completely conjugated pi-electron system. Examples, without limitation, of heteroaryl groups include pyrrole, furane, thiophene, imidazole, oxazole, thiazole, pyrazole, pyridine, pyrimidine, quinoline, isoquinoline and purine. The heteroaryl group may be substituted or unsubstituted.
Without being bound by a particular theory, the rational behind using aryl ether acrylate monomers is their relatively flexible result-polymer compared to straight chain aryl alkyl methacrylate which adds to greater deforming ability into lens matrix without significantly compromising on refractive index and hydrophobicity.
Exemplary monomers that are suitable for use as a first monomer according to embodiments of the invention include 2-phenoxyethyl acrylate, 2-phenoxy ethyl methacrylate, 2-benzyloxy ethyl acrylate, 2-benzyloxy ethyl methacrylate and combinations thereof.
Other non-limiting examples of the first aromatic acrylate monomer according to some embodiments of the present invention, include 2-ethylphenoxy methacrylate; 2-ethylphenoxy acrylate; 2-ethylthiophenyl methacrylate; 2-ethylthiophenyl acrylate; 2-ethylaminophenyl methacrylate; 2-ethylaminophenyl acrylate; phenyl methacrylate; phenyl acrylate; benzyl methacrylate; benzyl acrylate; 2-phenylethyl methacrylate; 2-phenylethyl acrylate; 3-phenylpropyl methacrylate; 3-phenylpropyl acrylate; 4-phenylbutyl methacrylate; 4-phenylbutyl acrylate; 4-methylphenyl methacrylate; 4-methylphenyl acrylate; 4-methylbenzyl methacrylate; 4-methylbenzyl acrylate; 2-2-methylphenylethyl methacrylate; 2-2-methylphenylethyl acrylate; 2-3-methylphenylethyl methacrylate; 2-3-methylphenylethyl acrylate; 24-methylphenylethyl methacrylate; 2-4-methylphenylethyl acrylate; 2-(4-propylphenyl)ethyl methacrylate; 2-(4-propylphenyl)ethyl acrylate; 2-(4-(1-methylethyl)phenyl)ethyl methacrylate; 2-(4-(1-methylethyl)phenyl)ethyl acrylate; 2-(4-methoxyphenyl)ethyl methacrylate; 2-(4-methoxyphenyl)ethyl acrylate; 2-(4-cyclohexylphenyl)ethyl methacrylate; 2-(4-cyclohexylphenyl)ethyl acrylate; 2-(2-chlorophenyl)ethyl methacrylate; 2-(2-chlorophenyl)ethyl acrylate; 2-(3-chlorophenyl)ethyl methacrylate; 2-(3-chlorophenyl)ethyl acrylate; 2-(4-chlorophenyl)ethyl methacrylate; 2-(4-chlorophenyl)ethyl acrylate; 2-(4-bromophenyl)ethyl methacrylate; 2-(4-bromophenyl)ethyl acrylate; 2-(3-phenylphenyl)ethyl methacrylate; 2-(3-phenylphenyl)ethyl acrylate; 2-(4-phenylphenyl)ethyl methacrylate; 2-(4-phenylphenyl)ethyl acrylate; 2-(4-benzylphenyl)ethyl methacrylate; and 2-(4-benzylphenyl)ethyl acrylate, and the like.
Additional examples for suitable first monomers include naphthyl acrylates, dicyclopentyloxy acrylates, dicyclopentyl acrylates, nonylphenoxy polyethyleneglycol 200 acrylates, nonylphenoxy polyethyleneglycol 400 acrylates, alkoxylated phenol acrylates, 2-methacryloyloxyethyl 2-hydroxy propyl phthalates, 2-acryloxy ethyl-2-hydroxy ethyl phthalates, 2-hydroxy-3-phenoxy propyl acrylates, neopentyl glycol benzoate acrylates and the likes.
According to some embodiments of the present invention, the concentration of the first monomer ranges from 52% to 59% of the total weight of the composition.
The second monomer (class) is another aromatic acrylate monomer characterized as forming, upon polymerization thereof, a second homopolymer having a Tg lower than the Tg of the first homopolymer, which is derived from the first monomer, by 2 to 30 degrees centigrade (° C.).
Non-crystalline polymeric solids are referred to as amorphous materials (atoms or molecules are not arranged in a lattice that repeats periodically in space). For all amorphous solids, whether glasses, organic polymers, and even metals (although having a lattice), Tg is the critical temperature that separates their glassy and rubbery behaviors. A glass is defined as a material that has no long-range atomic or molecular order and is below the temperature at which a rearrangement of its atoms or molecules can occur. On the other hand, a rubber is a non-crystalline solid whose atoms or molecules can undergo rearrangement. If a material is at a temperature below its Tg, large-scale molecular motion is not possible because the material is essentially frozen. If it is at a temperature above its Tg, molecular motion on the scale of its repeat unit (such as 50-mer in a polymer) takes place, allowing it to be “soft” or “rubbery”. It is noted that the term “Tg” is applies herein to non-crystalline solids, which are mostly either “glasses” or “rubbers”.
Hence, the phrases “glass transition temperature” or “rubber-glass transition temperature”, as used herein in the context of polymers, refers to the temperature at which the Gibbs free energy is such that the activation energy for the cooperative movement of about 50 elements (50-mer) of the polymer is exceeded compared to a reference point, meaning that molecular chains are able to slide past each other when a force is applied. A glass transition temperature of a non-crystalline material, such as a polymer, is the critical temperature at which the material changes its behavior from being “glassy” to being “rubbery”, while lowering the temperature across the Tg affords vitrification. “Glassy” in this context means hard and brittle (and therefore relatively easy to break), while “rubbery” means elastic and flexible and can absorb kinetic energy without shuttering.
According to some embodiments of the present invention, the chemical structure of the second monomer can follow the same chemical rational characterizing the first monomer, with the difference that the second monomer is selected according to the Tg characterizing the second homopolymer being lower than the Tg of the first homopolymer by 2-30° C.
The choice of a second aromatic monomer according to embodiments of the invention include, depends on the choice of the first monomer as difference in relative Tg is the criterion for selecting the second monomer. Therefore, there is an overlap in the range of options for the first and the second monomers.
Exemplary monomers that are suitable for use as a second monomer according to embodiments of the invention include, but are not limited to 2-phenylethyl acrylate, benzyl acrylate, 2-chlorophenyl acrylate, 4-methyl benzyl acrylate, 2,4,6-tribromophenyl acrylate, pentabromophenyl acrylate and any combinations thereof.
According to some embodiments of the present invention, the concentration of the second monomer ranges from 15% to 19% of the total weight of the composition.
It is noted herein that some ophthalmic and ocular devices, and particularly implantable devices, are required to avoid posterior capsular opacification (PCO) after cataract replacement surgery. This adverse effect relates also to the tackiness of the composition. To control tackiness, suitable monomers are selected for the co-polymeric composition, while not compromising the refractive index of the resulting composition. Hence, the co-polymeric composition presented herein exhibits tackiness to some degree so as to avoid PCO, and therefore tackiness should be high enough to reduce PCO, and low enough so as not to hinder handling.
Thus, the first monomer is meant to be restricted to the above-mentioned range, since the first monomer is characterized by a relatively higher Tg which makes the resulting polymer less tacky than the polymer resulting from the second monomer. These formulation restrictions confer relatively low tackiness without compromising the target refractive index. At the same time, the reason for keeping a high Tg monomer (higher than a low Tg monomer), is to confer mechanical strength to the multifocal ophthalmic device, which increases due to higher crystallinity imparted to the resulting polymer.
It is further noted herein that according to some embodiments of the present invention, a relatively high Tg aryl monomer is used as a major constituent, while the prior art teaches the use of lower Tg aryl monomer as a major part of the composition. For example, U.S. Pat. No. 5,290,892 teaches the use of 2-phenyl ethyl acrylate in higher amount compared to 2-phenyl ethyl methacrylate, while methacrylate compounds have higher Tg compared to corresponding acrylate compound. Together it forms at least 80% of the composition taught in U.S. Pat. No. 5,290,892.
The third monomer (class) is characterized as forming, upon polymerization thereof, a third homopolymer having a Tg lower than 37° C. Thus, the third monomer is the component which has a notable effect on the flexibility of the obtained composition of the multifocal ophthalmic device presented herein, conferring softness and improving its capability to recover from deformation. The capacity to recover quickly from deformation (reformability) is required by an ophthalmic device when applied to the eye after folding and while following the shape shifts of the eye.
Exemplary monomers that are suitable for use as a third monomer according to embodiments of the invention include, but are not limited to, cellosolve methacrylate, methoxy ethyl acrylate, polyethylene glycol monomethacrylate, 1-dihydroxyperflurobutyl methacrylate, 2,5-dibromopropyl methacrylate, hexyl methacrylate, glycerol monomethacrylate, trifluroethyl methacrylate, butyl methacrylate, n-ocyl/isooctyl methacrylate, n-decyl/isodecyl methacrylate, ethyl methacrylate, ethylene triglycol methacrylate, butyl diglycol methacrylate, methoxy polyethylene glycol 350 methhacrylate, methoxy polyethylene glycol 500 methhacrylate, methoxy polyethylene glycol 1000 methhacrylate, methoxy polyethylene glycol 2000 methhacrylate. methoxy polyethylene glycol 5000 methhacrylate, polypropylene glycon methacrylate, ethoxytriglycol methacrylate, 2-ethoxyethoxy ethyl methacrylate, methoxy triethyleglycol methacrylate, phenoxy polyethylene glycol monomethacrylate and any combinations thereof.
According to some embodiments of the present invention, the concentration of the third monomer ranges from 11% to 15% of the total weight of the composition.
It is noted herein that use of aryl ether acrylate and aryl alkyl acrylate, such as 2-phenoxy ethyl acrylate and 2-phenyl ethyl acrylate, gives superior results over the use of methacrylate and acrylate of same pendant group as described in the art.
Methacrylate groups are known to increase the strength and rigidity of the resulting composition, since methacrylate compounds exhibit side chain crystallization thereby increasing strength and rigidity. According to some embodiments of the present invention, it is suggested herein to introduce high Tg aryl ether acrylate monomer which also imparts flexibility to the co-polymeric composition, enabling 20D IOL delivery even through a sub 2 mm incision in a wound assisted surgical technique. An additional advantage of using aryl ether acrylate is its relatively less tacky nature compared to aryl alkyl methacrylate.
By using lesser amount of aryl acrylate monomer, polymer of relatively low refractive index is prepared to avoid glare/internal reflection problem at the same time, refractive index is maintained to a level that it would enable the lens to go through sub 2 mm incision.
For increasing strength and reformability, monomers like methoxy ethyl methcaylate are used. Its Tg is lower than 37° C. and it forms relatively hydrophobic polymer than conventional 2-ethoxy ethyl methacrylate. In general, in the pendant ether group, odd number of methylene (CH₂) gives optimal results. Examples include methoxy ethyl acrylate, propoxy ethyl acrylate, pentoxy ethyl acrylate and the likes.
The fourth monomer (class) is a hydrophilic monomer which is characterized as forming, upon polymerization thereof, a fourth homopolymer exhibiting a capacity to absorb water to at least 20% of its dry weight.
Water content of the homopolymer made from hydrophilic monomer should absorb enough so as to conform to the requirement of ophthalmic devices such as contact lenses and IOLs. After extraction of the leachables from the multifocal ophthalmic device, a process that is discussed hereinbelow, vacuoles may form in the product. Hence, all hydrophobic polymeric compositions exhibit vacuoles and some water absorption. When ophthalmic device comes in a contact with water or another aqueous medium, these media would tend to concentrate at the vacuoles.
Prime purpose of using a hydrophilic monomer is to uniformly disperse the water in the matrix. After putting the ophthalmic device in physiological medium like normal saline or highly pure water, these vacuoles give rise to white spots. To overcome this problem, hydrophilic monomer would disperse water uniformly rather than allowing water to concentrate in voids and vacuoles. This uniform dispersion gives rise to clear and spotless lenses. It also helps to increase the strength of the matrix and to control its tackiness.
Some commonly available hydrophilic monomer absorbs more than 20% of the total weight of their corresponding homopolymer. If the required water content in the multifocal ophthalmic device should be kept bellow 20%, other monomers can be selected so as to counter-effect the absorption of water.
The forth monomer is also effective to reduce tackiness of the co-polymeric composition presented here, as well as to improve its mechanical properties, as well as to uniformly disperse water molecules throughout the matrix at a wide temperature change.
As used herein, the phrase “hydrophilic monomer” refers to compounds which produce hydrogel-forming homopolymers, namely homopolymers which become associated with substantial amounts of water (for example, at least 20% based on the weight of the dry homopolymer), and which physically swell as a result of such association.
Exemplary fourth monomers include, without limitation, alkoxy alkyl (meth)acrylate; N-vinyl pyrrolidone; hydroxyalkyl acrylates and hydroxyalkyl methacrylates, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 2,3-dihydroxypropyl acrylate, 2,3-dihydroxypropyl methacrylate and the like; acrylamide; N-alkyl acrylamides such as N-methyl acrylamide, N-ethyl acrylamide, N-propyl acrylamide, N-butyl acrylamide and the like; acrylic acid; methacrylic acid; and the like and mixtures thereof.
Additional exemplary monomers that are suitable for use as a fourth monomer according to embodiments of the invention include, but are not limited to, hydroxyl ethyl methacrylate, glycerol monomethacrylate, ethylene triglycol methacrylate, butyl diglycol methacrylate, methoxy polyethylene glycol 350 methhacrylate, methoxy polyethylene glycol 500 methhacrylate, methoxy polyethylene glycol 1000 methhacrylate, methoxy polyethylene glycol 2000 methhacrylate, methoxy polyethylene glycol 5000 methhacrylate, polypropylene glycon methacrylate, ethoxytriglycol methacrylate, methoxy triethyleglycol methacrylate, phenoxy polyethylene glycol monomethacrylate and any combinations thereof.
According to some embodiments of the present invention, the concentration of the fourth monomer ranges from 7% to 9% of the total weight of the composition.
As used herein, the phrase “cross-linking monomer” refers to a substance that promotes or regulates intermolecular covalent, ionic, hydrophobic or other form of bonding between polymer chains, linking them together to create a network of chains which result in a more rigid structure. Crosslinking monomers, according to some embodiments of the present invention, contain at least two reactive groups that are reactive towards a variety of groups, including double bonds, sulfhydryls and amines, and create chemical bonds between two or more polymer molecules. Crosslinking monomers include homo-bifunctional crosslinking monomers that have two identical reactive end groups, and hetero-bifunctional crosslinking monomers which have two different reactive end groups. These two classes of crosslinking monomers differ primarily in the chemical reaction which is used to effect the crosslinking step, wherein homo-bifunctional crosslinking monomers will require a one step reaction, and hetero-bifunctional crosslinking monomers will require two steps to effect the same. While homo-bifunctional crosslinking monomers have the tendency to result in self-conjugation, polymerization, and intracellular cross-linking, hetero-bifunctional agents allow more controlled two step reactions, which minimize undesirable intramolecular cross reaction and polymerization. Crosslinking monomers are further characterized by different spacer arm lengths. A crosslinking monomer with a longer spacer arm may be used where two target groups are further apart and when more flexibility is desired.
Exemplary crosslinking monomers include, without limitation, butanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, diallyl fumarate, allyl (meth)acrylate, vinyl (meth)acrylate, trimethylolpropane tri(meth)acrylate, methacryloyloxyethyl (meth)acrylate, divinylbenzene, diallyl phthalate, diallyl adipate, triallyl diisocyanate, α-methylene-N-vinylpyrrolidone, 4-vinylbenzyl(meth)acrylate, 3-vinylbenzyl (meth)acrylate, 2,2-bis((meth)acryloyloxyphenyl)hexafluoropropane, 2,2-bis((meth)acryloyloxyphenyl)propane, 1,4-bis(2-(meth) acryloyloxyhexafluoroisopropyl)benzene, 1,3-bis(2-(meth)acryloyloxyhexafluoroisopropyl)benzene, 1,2-bis(2-(meth) acryloyloxyhexafluoroisopropyl)benzene, 1,4-bis(2-(meth) acryloyloxyisopropyl)benzene, 1,3-bis(2-(meth) acryloyloxyisopropyl) benzene, 1,2-bis(2-(meth) acryloyloxyisopropyl)benzene, and the like. These crosslinking monomers can be used solely or in a combination use of two or more thereof. Among those, ethylene glycol dimethacrylate and butanediol diacrylate are widely use effect controllable flexibility, desired mechanical strength, improved capability of deformation recovery, and increased co-polymerizable property.
Additional exemplary monomers that are suitable for use as a fifth monomer according to embodiments of the invention include, but are not limited to ethylene glycol dimethacrylate, 1,4-butane diol diacrylate, glycerol dimethacrylate, allyl methacrylate, 1,6 heaxane diol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexane diol dimethacrylate and any combinations thereof.
According to some embodiments of the present invention, the concentration of the fifth monomer ranges from 2% to 3.5% of the total weight of the composition.
The amount of the fifth monomer (crosslinker) depends on selection of the prior monomers. It is added to have an optimal shape recovery, to lessen the extractables and reduce glistening. An excess amount may increase glistening of the multifocal ophthalmic device after introduction into physiological medium. Lesser amount may result into loss of strength, higher extractables (more vacuoles) and slower shape recovery.
In addition, the co-polymeric compositions presented herein can include a variety of additional or alternative ingredients, feature additives and the likes. Examples include, without limitation, UV blockers, dyes, light-stabilizers, coating materials, pharmaceuticals (therapeutic agents), cell receptor functional groups, protein groups, viscosity agents (e.g., thickeners or thinners), diluents, combinations thereof or the like.
As discussed hereinabove, each and every constituent in the co-polymeric compositions presented herein, as well as their relative proportion in the making thereof, contribute to the wide range of requirements and necessary characteristics of lens body of the device made from these compositions.
For example, according to some embodiments of the present invention, the lens body of the device made from the compositions presented herein exhibit visible light transmission of at least 97% of incident visible light, as determined according to ASTM D 1003 standard and/or ISO 11979-2:2000 standard.
In addition, or alternatively, the lens body of the device made from the compositions presented herein exhibit a refractive index of at least 1.53, as determined according to the ASTM D 542-00(2006) standard.
In addition, or alternatively, according to some embodiments of the present invention, the compositions used to manufacture the lens body of the device presented herein exhibit a loop pull force mechanical strength of at least 60 grams, at least 50 grams or at least 40 grams, as determined according to the ISO 11979-3:2006 standard.
In addition, or alternatively, the compositions used to manufacture the lens body of the device presented herein are characterized by a glass transition temperature not higher than 5° C., not higher than 10° C. or not higher than 15° C., as determined according to the ASTM D3418-03:2000 standard.
In addition, or alternatively, Shore A hardness exhibited by lens body of the device prepared from the compositions according to some embodiments of the present invention, ranges from 77 to 80, as determined according to the ASTM D2240:2000 standard.
In addition, or alternatively, according to some embodiments of the present invention, the co-polymeric compositions presented herein exhibit an unfolding time of less than 6 seconds for full recovery of original shape injected through a sub 2 mm cartridge at room temperature. Such requirement is important when the device is placed in position by inserting it under leaving tissue with a narrow gauge cartridge (sub 2 mm).
When using the co-polymeric compositions according to some embodiments of the present invention, the resulting multifocal ophthalmic device is characterized by having essentially no internal reflections, and further have essentially no vacuoles and/or perceivable glistening as determined by visual inspection at a magnification of 50×.
One of the requirements of the multifocal ophthalmic device presented herein, involving leachable content, is clearly met by the co-polymeric compositions presented herein, which have a leachable content of less than 0.6%, as determined according to the ISO 11979-5:2006 and/or the ISO 11979-5:2006 standards.
According to some embodiments of the present invention, the multifocal ophthalmic device made from the compositions presented herein are essentially tack-free, as determined according to the ASTM D 3654 standard.
The multifocal ophthalmic device made from the co-polymeric compositions presented herein can also be referred to as a hydrophobic diffractive ophthalmic device and can be, for example, a hydrophobic diffractive IOL.
According to some embodiments of the present invention, the co-polymeric composition for making the device or body lens of the device described herein further includes a radiation-resistant compound, which is typically referred to as a UV-blocker agent or additive, UV-light stabilizer and/or UV-absorbent agent. The terms “UV-blocker” and “UV-stabilizer”, and grammatical diversions and inflections thereof, are used herein interchangeably, since stabilizing a polymeric composition against the degradation caused by UV-light stems also from the capacity to block UV-light by the composition.
The role of protection from UV damages, both to the eye (protect light sensitive retina) and the co-polymeric composition itself, can be taken by one type of UV-blocker or a combination of several different compounds, some embedded and some co-polymerized with the composition. The UV-blocker can thus be a polymerizable constituent, which presents advantages in terms of leachability of the agent, and it can be an embedded constituent, namely incorporated consistently in the matrix of the polymeric composition so as not to leach out.
It is noted herein that UV-protection is particularly desirable for ophthalmic devices such as the multifocal ophthalmic device presented herein, which may be located within the eye for extended periods of time (e.g., greater than 6 months, a year, several years or more) as opposed to, for example, disposable contact lenses. As such, it is highly desirable for these types of devices to exhibit longer term resistance to degradation caused by radiation exposure.
An ultra-violet absorbing material (UV-blocker additive) can be any natural or synthetic compound which absorbs ultraviolet light, i.e., light having a wavelength shorter than about 400 nm, but does not absorb any substantial amount of visible light. A natural UV-blocker can be a curcuminoid compound, as defined and discussed hereinbelow. The ultraviolet absorbing compound is incorporated into the monomer mixture and is embedded or entrapped in the polymer matrix when the monomer mixture is polymerized. According to some embodiments of the present invention, the UV-blocker provide a transmission cut-off above a wavelength of 385 and typically provide cut-off in the short wavelength visible (410-430 nm) region of the electromagnetic spectrum. Such chromophores can then provide desired protection to the human eye and/or the device material from UV radiation (<400 nm). Suitable UV-blockers can also be referred to as UV/short wavelength visible light absorbers, dye or chromophores.
Unless otherwise specified, “cut-off” means the wavelength at which light transmission does not exceed 1%. “1% cut-off” means the wavelength at which light transmission does not exceed 1%. “10% cut-off” means the wavelength at which light transmission does not exceed 10%.
Typical ultraviolet absorbing compounds, based on synthetic chromophores, include substituted benzophenones, such as 2-hydroxybenzophenone, and 2-(2-hydroxyphenyl)benzotriazoles. According to some embodiments of the present invention, the ultraviolet absorbing compound may be co-polymerizable with the monomers and is thereby firmly embedded in the polymer matrix. In this way possible leaching of the ultraviolet absorbing compound out of the lens and into the interior of the eye is minimized. Suitable co-polymerizable ultraviolet absorbing compounds include substituted 2-hydroxybenzophenones as disclosed in, for example, U.S. Pat. No. 4,304,895 (incorporated by reference as fully set forth herein) and 2-hydroxy-5-acryloxyphenyl-2H-benzotriazoles disclosed in U.S. Pat. No. 4,528,311 (incorporated by reference as fully set forth herein). Alternatively, the ultraviolet absorbing compound is 2-(3′-methallyl-2′-hydroxy-5′methyl phenyl) benzotriazole.
Other synthetic ultraviolet absorbing compounds include phenol-2-(5-chloro-2H-benozotriazol-2-yl)-6-(1,1-)dimethyl-4-methyl (Tinuvin® 326), 4-benzoyl-3-hydroxyphenyl-2-methacrylate, 2-[4-(2h-1,2,3-benzotriazol2-yl)-3-hydroxyphenoxy]ethyl-2-methacrylate and combination thereof.
Optic devices based on co-polymeric compositions may also comprise a polymerizable or embedded yellow dye that attenuates medium- to long-wavelength (430-500 nm) blue light. Such dyes and other useful chromophores are described in U.S. Pat. No. 7,691,918, which is fully incorporated herein for all purposes.
Yellow dye gives a yellowish tint to lens; natural lens tends to get yellow as age of patient progresses. Yellow tinted artificial lens gives the elderly patient the appearance of a natural lens. The yellow dye also provides protection from visible blue light which may lead to age related macular degeneration.
Presently known UV-blocking additives and synthetic chromophores, used in polymeric compositions for ophthalmic and ocular devices, may suffer from one or more drawbacks, including biocompatibility, physical, mechanical and chemical stability, and manufacturing factors (e.g., cost and complex syntheses).
Polymeric and Co Polymeric Compositions Containing Curcuminoid as a Natural UV-Blocker:
According some embodiments of the present invention, the lens body of the multifocal ophthalmic device presented herein, which comprises a co-polymeric composition (also referred to herein as a co-polymer or a hydrophobic co-polymeric composition) described herein, further includes a natural UV-blocker in the form of a curcuminoid compound incorporated in or on the co-polymeric composition and/or the lens body.
According to some embodiments of the present invention, the pre-polymerization mixture of monomers includes at least 50 percents acrylate monomers.
It is noted herein that the benefits of incorporating a curcuminoid compound in ophthalmic and ocular devices applies to any polymeric or co-polymeric composition or a lens body of a device comprising the same. Thus, an ophthalmic or ocular device, according to some embodiments of the present invention, can be made from any suitable polymeric or co-polymeric composition as known in the art, and the curcuminoid compound can be added to the pre-polymerized mixture of the composition before curing, or applied thereon after curing, as described herein.
According to another aspect of the present invention, there is provided a multifocal ophthalmic device which includes a lens body which is formed with a plurality of concentric annular zones separated by slanted steps, wherein the concentric zones effect both diffraction and refraction of incident light, while the steps are substantially devoid of any diffractive or refractive power, wherein the lens body is made of a polymeric or co-polymeric composition which includes at least one curcuminoid compound, as presented hereinabove, incorporated in the composition or on the lens body as a mean to provide UV-light stabilization.
The lens body of the multifocal ophthalmic device can be made from any suitable polymeric or co-polymeric composition as known in the art, and the curcuminoid compound can be added to the pre-polymerized mixture of the composition before curing, or applied thereon after curing, as described herein. The curcuminoid compound is therefore incorporated into the composition as described hereinabove.
In some embodiments, a polymeric or co-polymeric composition which includes a curcuminoid compound is derived from a pre-polymerization mixture of monomers that includes at least 50 weight percents acrylate monomers.
Exemplary acrylate monomers suitable for use in the context of these embodiments include, but are not limited to, an acrylate, a methacrylate, an aryl acrylate and an aryl methacrylate.
As demonstrated in the Examples section that follows, one exemplary co-polymer which includes a curcuminoid compound can be formed from one or more monomers such as, but not limited to, 2-phenoxy ethyl methacrylate (POEMA), cyclohexyl acrylate (CHMA) and 1,4-butane diol diacrylate (BDDA). An exemplary composition, according to some embodiments of the present invention, is formed, for example, from a pre-polymerization mixture containing 50-70% 2-phenoxy ethyl methacrylate (POEMA), 20-50% cyclohexyl acrylate (CHMA) and 1-5% 1,4-butane diol diacrylate (BDDA), and 0.001-0.5% curcuminoid compound, each measured by dry weight percentages of the total dry weight of the pre-polymerization mixture. Other constituents may also be included in minor amounts, such as a catalyst (a polymerization initiator agent), cross-linking monomers, colorant/dye additives and the likes.
Optionally, according to embodiments of this aspect, the co-polymeric composition includes a polymeric backbone composed of a plurality of backbone units covalently linked to one another, which is derived from a pre-polymerization mixture of monomers having a unique formulations as presented hereinabove.
Hence, according to another aspect of some embodiments of the present invention, there is provided a multifocal ophthalmic device which includes a lens body which is formed with a plurality of concentric annular zones separated by slanted steps, wherein the concentric zones effect both diffraction and refraction of incident light, while the steps are substantially devoid of any diffractive or refractive power, wherein the lens body is made of a hydrophobic co-polymeric composition, as described herein.
Combining the beneficial features imparted by the curcuminoid compound as described herein with the beneficial features of the co-polymeric composition described herein result in a vacuole free, glistening free, internal reflection free and tack free co-polymeric composition, which is protected from the damaging effects of UV light and meet the requirement of tensile strength, deformation recovery ability and mechanical, optical, biological and toxicological requirements.
As can be seen in the Examples section that follows, the present inventors have successfully incorporated curcumin in an exemplary co-polymeric composition which is suitable for use in ophthalmic and ocular devices such as the multifocal ophthalmic device discussed hereinabove, and were able to obtain a desirable level of transparency towards visible light and at the same time opacity with respect to ultraviolet light, using a relatively low concentration of curcumin.
Thus, it has been demonstrated that naturally occurring (natural) compounds such as curcuminoids, which are generally recognized as safe for human consumption and somatic use, can be used with certain polymers or co-polymers, such as substantially acrylate-based polymers, to form lasting compositions with suitable UV/blue light blocking and UV-light stabilization properties. It has been recognized that curcuminoids used in ophthalmic and ocular devices as blue/UV light blockers would overcome the limitations and possible impairments associated by the use of synthetic compounds such as diphenyl-azo-based, benzotriazole-based and benzophenone-based UV-blockers and the like.
It has been further demonstrated by some of the present inventors that curcuminoids can be used effectively even at low concentration in the polymeric composition, relative to the concentration required for benzophenone-based and benzotriazole-based UV-blockers, in order to achieve comparable effective UV-blocking. A low concentration of the UV-blockers not only affects the cost of the resulting product but also affects the visual clarity of the product and its final dimensions. Furthermore, the proven UV-blocking effectiveness of curcuminoids would make it highly suitable for in the multifocal ophthalmic device presented herein. Thus, relatively low concentrations of the curcuminoids are sufficient to exhibit the desired activity. Hence, according to some embodiments of the present invention, the concentration of the curcuminoid compound in the composition ranges from 0.0002 weight percentage to 1 weight percentage or from 0.001 weight percentage to 0.5 weight percentage of the total weight of the composition. Any value lower than 1 weight percent is contemplated, hence any value lower than 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05, 0.001 and any value lower than 0.0005 weight percent is contemplated as well.
It has been further demonstrated that curcuminoids, unlike many known synthetic phenol-containing UV-blockers, do not inhibit or retard the rate and/or degree of polymerization, when added to the pre-polymerization mixture.
The use of compounds of the curcuminoid family allows selecting a compound with certain optical characteristics, such as, for example, a particular light-absorption range and a particular color or lack thereof.
Without being bound by any particular theory, it is suggested that the transparency of the co-polymeric composition is maintained upon incorporating curcumin therein due to the relatively low concentration of the embedded curcumin. Such low concentration is sufficient due to the effective UV-absorption characteristics of curcuminoids and the surprising finding that curcuminoids do not leach out of polymers or co-polymers derived from pre-polymerization mixtures having at least 50 percents acrylic monomers.
As further demonstrated in the Examples section that follows, curcumin was found to be incorporated firmly and consistently in an exemplary polymeric composition, as confirmed by the stability of its concentration in the tested composition before and after the tested composition was subjected to extended cycles of extraction in organic solvents which are known to dissolve curcumin.
The term “incorporated”, as used herein, refers to the physical state of one substance in a composition containing other substances. In the context of some embodiments of the present invention, an incorporated curcuminoid compound is incorporated within the co-polymer composition described herein such that the curcuminoid compound is at least partially surrounded by the co-polymeric composition and entrapped thereby.
In some embodiments, the incorporated curcuminoid compound is distributed within the polymeric or co-polymeric composition in a uniform and sustainable form, and is enclosed in the surrounding mass.
According to some embodiments of the present invention, the curcuminoid compound incorporated within the polymeric or co-polymeric composition is not covalently attached to one or more constituents of the polymeric or co-polymeric composition. In some embodiments, the curcuminoid compound interacts with the polymeric or co-polymeric composition via physical interactions, such as, for example, entanglement, absorption, adsorption and/or entrapment, and not via chemical interactions such as covalent, ionic, or hydrogen bonds.
Curcuminoids constitute a versatile group of chromophore-containing substances, which can be selected by their light absorption properties to suit a particular application.
In general, curcuminoids are polyphenols characterized by a pronounced yellow color, and most of the naturally occurring curcuminoids, including curcumin itself, have been recognized as generally safe for human consumption and suitable for pharmaceutical purposes.
The term “curcuminoid”, as used herein, is used to collectively describe curcumin, as well as derivatized curcumin compounds. Derivatized curcumin compounds have a curcumin backbone structure, and optionally have one or more different chemical groups (substituents) attached at various positions of the curcumin backbone structure. A derivatized curcumin compound may differ from curcumin by chemical and physical characteristics, such as solubility, reactivity, light interaction and the likes, as a result of its substituents.
Curcuminoid compounds according to some embodiments of the present invention, can be collectively represented by General Formula I:
According to some embodiments of the present invention, each of D₁and D₂is individually selected from the group consisting of O, N, S or C(aryl), whereas D₁and D₂may be connected directly or via a connecting atom to form a conjugated ring (aryl, heteroaryl etc.); and wherein each of R₁-R₁₅is individually selected from the group consisting of alkyl, alkoxy and hydroxy.
An “aryl” group refers to an all-carbon monocyclic or fused-ring polycyclic (i.e., rings which share adjacent pairs of carbon atoms) groups having a completely conjugated pi-electron system. Examples, without limitation, of aryl groups are phenyl, naphthalenyl and anthracenyl. The aryl group may be substituted or unsubstituted.
A “heteroaryl” group refers to a monocyclic or fused ring (i.e., rings which share an adjacent pair of atoms) group having in the ring(s) one or more atoms, such as, for example, nitrogen, oxygen and sulfur and, in addition, having a completely conjugated pi-electron system. Examples, without limitation, of heteroaryl groups include pyrrole, furane, thiophene, imidazole, oxazole, thiazole, pyrazole, pyridine, pyrimidine, quinoline, isoquinoline and purine. The heteroaryl group may be substituted or unsubstituted.
The curcuminoid compound utilized in embodiments of the present invention can be a naturally-occurring curcuminoid or a synthetically prepared curcuminoid, with naturally-occurring curcuminoids being more desirable.
Exemplary curcuminoid compounds that are suitable for use in the context of some embodiments of the present invention include, but are not limited to, curcumin (illustrated in the scheme below), bisdemethoxycurcumin, monodemethoxycurcumin and tetrahydroxycurcumin, which are all natural curcuminoids found in plants such as the curcuma species.

(1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-6-heptadiene-3,5-dione (Curcumin)

The naturally occurring curcuminoids differ from one another in both the number and position of the methoxy groups, and all exhibit a keto-enol tautomerism in the mid-section of the chromophore chain. These curcuminoids differ in their light absorbing and free radical scavenging properties. All of the naturally-occurring curcuminoids may serve as efficient UV-blockers and/or stabilizers, in the context of embodiments of the present invention. For instance, some natural curcuminoid sources contain tetrahydroxycurcumin (THC), which is a colorless compound, which can be used as a UV stabilizer in applications where yellow color is not required or desired.
THC is a suitable curcuminoid compound, according to some embodiments of the present invention, in applications where yellowish tint is to be avoided.
Curcuminoid compounds can be extracted as naturally occurring substances or be prepared synthetically, and can be used as mixtures thereof or as isolated species. Curcuminoid compounds which are also encompassed by the present embodiments are disclosed in, for example, U.S. Pat. No. 3,479,345, U.S. Patent Application Nos. 20030153512, 20060276536, 20070060644, 20070204412, 20080200478, 20100010232, 20100048901, 20100048901 and 20100087527, all of which are incorporated herein by reference as if fully set forth herein.
As discussed herein, substances that can leach (be extracted) out of a matrix may cause several adverse effects, such as harming the biological environment (tissue) surrounding the matrix, and reducing the effectiveness of the composition in, for example, blocking UV light. Hence, the characteristic behavior of the curcuminoid in polymeric or co-polymeric compositions can be referred to as low leachability (from the term “leachable”) with respect to the matrix constituents and with respect to the curcuminoid compound, and can be defined in terms of comparison of concentrations before and after an extraction process.
Low leachability is significant when a substance is used in implantable devices, since in such devices, long-term performance is desired.
The process by which the incorporation of the curcuminoid compound is evaluated is also referred to as the extraction step of unreacted components and diluents (UCDs) from the cured composition, which is discussed in detail herein, and exemplified in the Example section that follows below.
According to some embodiments of the present invention, there is no perceivable difference in the concentration of the curcuminoid compound after the extraction process for removal of UCDs. Hence, according to some embodiments of the present invention, the polymeric or co-polymeric composition described herein as comprising a curcuminoid compound is such that the concentration of the curcuminoid compound in the composition does not decrease as a result of extraction step of UCDs, or decreases by no more than 0.0001%, when subjected to an extraction process in an organic solvent, including also solvents which can readily dissolve the curcuminoid compound.
As discussed herein, a curcuminoid compound can be selected according to the desired light-absorption properties which are required from the composition.
According to some embodiments of the present invention, the curcuminoid can be selected such that the composition is substantially transparent to light at a wavelength ranging from about 400 to about 800 nm, and it can also be selected such that the composition is substantially opaque to light at a wavelength ranging from about 190 to about 440, or substantially opaque to light at a wavelength ranging from about 100 to about 400.
Such optical properties were demonstrated for compositions comprising curcumin, bisdemethoxycurcumin or monodemethoxycurcumin, as the curcuminoid compound.
According to some embodiments of the present invention, the curcuminoid can be selected such that the composition is substantially transparent to light at a wavelength ranging from about 490 to about 800 nm, and it can also be selected such that the composition is substantially opaque to light at a wavelength ranging from about 190 to about 440, or from about 100 to about 490. Such a composition is effective in reducing or essentially blocking the transmission of violet/blue light.
Such optical properties can be afforded when the curcuminoid compound is, for example, tetrahydroxycurcumin (THC).
As discussed above, UV-light is characterized by a wavelength ranging from 100-440 nm (some sources state that visible region starts from about 390 nm), violet is the color of the short-wavelength end of the human visible spectrum ranging approximately 380-450 nm, and blue light ranges 450-475 nm.
According to some embodiments of the present invention, the polymeric or co-polymeric composition as presented herein, which further comprises at least one curcuminoid compound as described herein is characterized by having UV-light blocking properties, wherein the UV-light is characterized by a wavelength ranging from 100 nm to 440 nm.
Some curcuminoid compounds exhibit yellow color which leads to absorption of visible blue and violet light. According to some embodiments of the present invention, the curcuminoid compound is such that it acts as a UV absorber as well as blue light blocker.
According to some embodiments, two different additives for radiation protection can be present in the composition, one for UV stabilization and another for visible blue light protection.
It is noted herein that the benefits of incorporating a curcuminoid compound in ophthalmic devices can apply also with body lens made from any polymeric or co-polymeric composition, as described herein.
Processes of Preparing a Multifocal Ophthalmic Device:
The multifocal ophthalmic device of the present embodiments can be fabricated in any technique known in the art. Generally, a plurality of concentric annular zones separated by slanted steps, wherein the concentric zones effect both diffraction and refraction of incident light, while the steps are substantially devoid of any diffractive or refractive power, are form on a polymeric or co-polymeric composition. The formation of zones and steps may be done by any convenient manufacturing means, including, for example, a computer-controllable manufacturing device, machining, polishing, casting, molding and the like, and as is discussed in further detail hereinbelow. The polymeric or co-polymeric composition on which the zones and steps are formed can be in a form of a fully shaped or partially shaped lens body, in which case the formation of zones and steps serves for forming the ophthalmic device directly by machining. Alternatively, the polymeric or co-polymeric composition can be cast in a mold, in which case the formation of zones and steps serves for forming a lens mold for mass fabrication of ophthalmic devices.
The polymeric or co-polymeric composition for making the multifocal ophthalmic device, according to some embodiments of the present invention, can be prepared by conventional polymerization techniques as known in the art, which include mixing the monomers and optional additives, such as UV-blockers, into a homogeneous pre-polymerization mixture, optional heating, degassing and adding additional ingredients, such a polymerization initiator such as a free radical polymerization initiator, and subjecting the mixture to polymerization conditions after casting the mixture into a mold.
These general processes allow adding any optional additive, such as the natural UV-blocker curcuminoid compound, at various steps of the process. For example, for preparing a co-polymeric composition as described herein, a mixture containing the five types of monomers is used. For preparing a polymeric or co-polymeric composition having a curcuminoid compound incorporated therein or thereon, a mixture containing aryl acrylate monomers as described herein is used.
Incorporation of the curcuminoid compound can be made while adding the curcuminoid compound to the pre-polymerization mixture or by contacting the composition with the curcuminoid compound and allowing it to be incorporated thereon. Some processes of preparing the multifocal ophthalmic device further include post-polymerization steps such as chemical treatments, extractions and mechanical shaping.
However, some processes may be more suitable for forming multifocal ophthalmic devices made from particular compositions, as presented herein.
Hence, according to an aspect of embodiments of the present invention, there is provided a process of preparing the polymeric or co-polymeric composition presented herein, which is effected by:
admixing a pre-polymerization mixture containing the monomers presented hereinabove, as well as other optional constituents and additives and a free radical polymerization initiator;
optionally degassing the pre-polymerization mixture so as to remove any dissolved gasses which may interfere with optical clarity of the composition by forming vacuoles;
heating said pre-polymerization mixture while stirring;
optionally degassing the pre-polymerization mixture again so as remove volatile residues after heating;
optionally admixing an additional amount of the initiator into the pre-polymerization mixture so as to obtain a polymerization reaction mixture;
admixing a curing agent into the reaction mixture;
casting the reaction mixture into a mold;
exposing the reaction mixture in the mold to curing conditions, to thereby obtain the co-polymer composition presented herein; and
subjecting the co-polymeric composition to a multiple extraction so as to rid it from unreacted contaminants.
According to some embodiments of the present invention, the pre-polymerization mixture comprises the first, second, third, fourth, and fifth monomers in their appropriate ratios, as described herein for a hydrophobic co-polymeric composition.
According to some embodiments of the present invention, one of the additives can be a curcuminoid compound, as discussed hereinabove.
Optionally, heating the pre-polymerization mixture while stirring is performed at 40° C. until the viscosity of pre-polymerization mixture reaches an optimal level (120 cps at 25° C.). The viscosity measurements are obtained from the torque applied on the stirring device.
Once all the monomers and other components are mixed together for polymerization, the polymerization reaction may be initiated by adding a radical polymerization initiator in a conventional manner to obtain the polymeric or co-polymeric composition according to some embodiments of the present invention.
The choice of initiator also determines the kinetics of the polymerization reaction. As discussed hereinabove, the molecular weight of the composition imparts properties to the multifocal ophthalmic device, such as glistening, mechanical properties, refractive index and transmittance. Molecular weight is inversely proportional to the half power of the initiator concentration.
The initiator, also referred to herein as a catalyst, is typically employed to initiate the polymerization of the monomers and/or carry out the crosslinking or thermosetting of the polymeric or co-polymeric compositions formed of those monomers, as presented herein. Thus, according to some embodiments of the present invention, the co-polymeric composition present herein further includes an initiator (a catalyst).
According to some embodiments of the present invention, the polymerization reaction follows a free-radical propagation mechanism. As known in the art concerning conventional polymerization methods, the free-radical polymerization reaction may be initiated, for example, by free radical initiators, either thermally or photochemically. When using a thermally initiated free radical polymerization reaction, the method is typically effected by heating gradually from room temperature to an elevated temperature, such as 130° C., and the temperature can be elevated stepwise and/or cycled. When the polymerization initiator is controlled photochemically, the polymerization reaction in initiated by irradiating the pre-polymerization mixture with electromagnetic radiation, such as microwave, ultraviolet light or radiation (y ray) after a radical polymerization initiator is added thereto. It is noted herein that two or more types of initiators may be combined to arrive at a more controlled and completed polymerization reaction.
According to some embodiments of the present invention, the initiation step is effected at relatively low temperatures as a function of the choice of initiator. According to some embodiments of the present invention, the co-polymeric composition includes a low temperature dissociation initiator which keeps the formed multifocal ophthalmic device fixed in position in the mold by avoiding significant expansion or contraction. Using such initiators makes the use of fused silica molds redundant, which in turn reduces the need for complex UV curing of the composition. Hence, according to some embodiments of the present invention, the initiator is a low temperature dissociation initiator.
According to some embodiments of the present invention, non-limiting examples of the initiator include bedicetyl peroxydicarbonate, tert-butyl peroxypivalate, diisobutyryl peroxide, dimyristyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxypivalate, tert-butyl peroxyneoheptanoate, di(2-neodecanoylperoxy-isopropyl)benzene, cumylperoxy-neodecanoate, 1,1,3,3-tetramethylbutylperoxy-neodecanoate, t-butylperoxy-neodecanoate, t-butylperoxy-neoheptanoate and any combinations thereof.
According to other embodiments of the present invention, the catalyst is selected from the group consisting of dicetyl peroxydicarbonate (such as Perkadox® 24L by Akzo Nobel Polymer Chemicals, India) and tert-butyl peroxypivalate (such as LUPEROX® 554M75 by Arkema Inc. Philadelphia, Pa., USA).
Non-limiting examples of a radical and/or thermal polymerization initiator include, for instance, azobisisobutyronitorile, azobisdimethylvaleronitrile, benzoyl peroxide, tert-butyl hydroperoxide, qumene hydroperoxide and the like, which can be used solely or in a combination use of two or more thereof.
Light-sensitive initiators (photopolymerization initiator) include, for a non-limiting example, photopolymerization initiators of benzoin compounds such as methyl orthobenzoyl benzoate, methyl benzoyl formate, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether and benzoin n-butyl ether, photopolymerization initiators of phenone compounds such as 2-hydroxy-2-methyl-1-phenylpropane-1-one, p-isopropyl-α-hydroxyisobutylphenone, p-tert-butyltrichloroacetophenone, 2,2-dimethoxy-2-phenylacetophenone, α,α-dichloro-4-phenoxyacetophenone, and N,N-tetraethyl-4,4-diaminobenzophenone, 1-hydroxycyclohexylphenylketone, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl) oxime, photopolymerization initiators of thioxanthone such as 2-chlorothioxanthone and 2-methylthioxanthone, dibenzosuberone, 2-ethylanthraquinone, benzophenone acrylate, benzophenone, benzil and the like.
The amount of the above-mentioned polymerization initiator is typically not less than 0.002 percent by weight, more preferably 0.01% by weight based on 100% of the total weight of the composition. Alternatively, the concentration of the initiator is not more than 10% by weight, or not more than 2% of the total weight of the composition.
The optional addition of initiator (also referred to herein interchangeably as a catalyst) prior to the casting stage, is meant to boost the completion of the polymerization reaction. As discussed hereinabove, additional initiator is added when the viscosity of the reaction mixture reaches about 120 cps.
According to some embodiments of the present invention, the process includes first adding an amount equivalent to about 20-40% of the total amount of the initiator in the first step of the process, and then adding about 60-80% of the total weight of the initiator.
After mixing and adding the initiator, the mixture is transferred through a filter into the mold. The viscosity at which the mixture is filtered is about 120-130 cps. The ophthalmic device is formed in the mold from the mixture directly into its complete form, avoiding further machining which in turn avoids local burning and machining related stresses. After casting or pouring the mixture in between two halves of the mold, thermal or photo curing stimulus is applied. Thermal curing is performed at room temperature to 80° C. with several ramping steps.
According to some embodiments of the present invention, filtering the reaction mixture may also precede the casting stage.
Once the reaction mixture is cast in a mold, the curing step can start. Exposure to curing conditions typically includes elevating the temperature and/or exposing the reaction mixture to high energy radiation. High temperatures are typically about 80° C., and the irradiation energy may range from 10 KJ/Kg to 50 KJ/Kg in order to further allow the co-polymeric composition to cure.
Curing agents and accelerators may also be employed in the formation of the co-polymeric composition according to some embodiments of the present invention. Various curing agents and accelerators are known and can be used in prescribed amounts or amounts experimentally found to be suitable. Typically, amounts of the curing agent, the curing agent accelerator or a combination thereof are between about 0.1% and about 8% by weight of the total weight of the composition. Curing agents and accelerators can be used in various amounts, which will typically depend upon the monomers and polymers being employed, any ambient conditions (e.g., heat, light or otherwise) being used for curing and/or other factors.
Examples of suitable curing agents include UV photoinitiators, peroxy catalysts (i.e., any catalyst including a peroxy group), oxide catalysts (i.e., any catalyst include an oxide group (e.g., a dioxide) or others known by the skilled artisan. One example of a peroxy catalyst is a tert-butyl peroxy-2-ethylhexanoate organic peroxide initiator, which is particularly suitable for thermal cure. One example of an oxide catalyst is 2,4,6-trimethylbenzoyldiphenylphosphine oxide, which is particularly suitable for blue light cure.
According to some embodiments of the present invention, the monomers, the initiator, the curing agent and optionally curing agent accelerator, a UV-blocker (radiation resistant compound), if present, and any other desired ingredients are combined together to form a master batch. The master batch is then exposed to an ambient stimulus, such as heat or light (e.g., blue light) which initiates polymerization and cross-linking reactions between the various monomers. The initiated master batch can be cast into molds (such as cast wafers) of desired geometry and can be secured in cure fixtures for forming the ophthalmic devices. It is advisable to add a crosslinking monomer in initial stage especially in the case where the polymerization reaction is performed at relatively low temperature.
The wafer molds are then typically cured through extended exposure to an ambient condition such as heat, light or both. For example, in one embodiment, the cast wafers are exposed to an elevated temperature (e.g., about 70° C.) for a first period of time (e.g., about 2 hours) and then ramped up to a second temperature (e.g., about 110° C.) for a second period of time (e.g., at least 10 minutes). In a second exemplary embodiment, the wafers are cured using blue light at a wavelength of about 405 nm to about 415 nm for a first period of time (e.g., about 3 hours) and then exposed to an elevated temperature (e.g., about 110° C.) for a second period of time (e.g., about one hour). Typically, the initiation, the curing or both are carried out in a low moisture (e.g., less than 1 ppm water) and low oxygen (less than 100 ppm) environment.
Alternatively, working at relatively low temperatures, from room temperature and up to 80° C. is advantageous, since it allows the polymerization and curing steps to complete post the casting stage (namely in the mold), without causing thermal distortion of the mold. This way a relatively low cost polypropylene mold can be used, instead of a costlier fused silica molds.
During the initial polymerization step it is possible to monitor the viscosity of the master batch mixture, for example by following the force applied to the mixing shaft.
Once the polymeric or co-polymeric composition is cured it can be cleansed from unreacted components and other leachables. The extraction of leachables may commence once the molded and cured composition is released from the mold.
According to some embodiments of the present invention, the extraction is effected by sequential immersion of the polymeric or co-polymeric composition in a series of baths, each containing a different solvent or solution, going from hydrophobic to hydrophilic in the order of sequence, thereby extracting unreacted contaminants from the composition.
Following the description of the embodiments of the present invention, provides co-polymeric compositions and processes for preparing the same, which are highly suitable for manufacturing implantable and non-implantable ophthalmic and ocular devices including multifocal ophthalmic devices. Following the above-described description of the embodiments affords vacuole free, glistening free, internal reflection free and tack free ophthalmic and ocular devices, which meet the requirement of tensile strength, deformation recovery ability and mechanical, optical, biological and toxicological requirements set by widely accepted standards of the art.
It is noted that even after the post-curing step, which further pushes the polymerization reaction to completion, some impurities from unreacted monomers and other contaminants remains in the composition. These impurities are commonly referred to herein as unreacted components, diluents and other leachable impurities. Under the term leachable impurities are also included filter membrane residues, boiling impurities, solvent remnants and other process contaminants.
To remove unreacted components and diluents (UCDs) and other leachable impurities from the cured composition formed as a multifocal ophthalmic device, and affect clinical viability of the lens body, the process of preparing such devices typically includes an extraction step. If the leachable substances are not extracted from the device, they may make the device uncomfortable to wear or even present a medical hazard. As used herein, “leachable substance” includes UCDs and other substances which are not bound to or embedded in the polymer and may be extracted from the composition (the matrix), for example, by leaching with water or an organic solvent. As used herein, the term “treat” means to expose a cured object or device, made from the composition presented herein, to an aqueous and/or organic solution which may also include at least one leaching aid. Treating a cured polymeric composition to remove UCDs and monitoring traces thereof is demonstrated in the Examples section which follows below using a curcuminoid compound as a light-stabilizer, which is not part of the polymeric backbone and therefore required not to leach out of the cured composition.
As used herein, a “leaching aid” is any compound that if used in an effective amount in an aqueous or organic solution to treat an ophthalmic device, and can assist in obtaining a device with an adequate amount of removal of leachable substances.
According to embodiments of the present invention, the process of preparing the lens body of a multifocal ophthalmic device from the co-polymeric composition presented herein may include a treatment of the cured co-polymeric composition. The treatment step can include exposing the cured composition to an aqueous and/or organic solution which constitutes or includes at least one leaching aid. In various embodiments, treatment can be accomplished, for example, via immersion of the device in a solution or exposing the device to a flow of solution or exposing the device to Soxhlet extraction. In various embodiments, treatment can also include, for example, one or more of heating the solution; stirring the solution; mechanical agitation or sonication of the solution; and increasing the level of leach aid in the solution to a level sufficient to facilitate adequate removal of leachable substances from the device.
According to some embodiments of the present invention, an organic or aqueous solution may constitute a leaching aid. According to other embodiments of the present invention, leaching aids can also be combined with organic solvents to improve the rate of release. For example, in some embodiments, ophthalmic devices such as lenses can be subjected to a treatment exposing the lens devices to a leaching aid and a GC Mass Spectrometer can be used to measure the level of one or more leachable substances in the lens devices. The GC Mass Spectrometer can determine whether treatment with a particular leaching aid is effective to reduce an amount of particular leachable substances present in the lenses to a maximum threshold amount. Accordingly, in some embodiments, a GC Mass Spectrometer can be used to check for a maximum threshold of leachable substances of approximately 300 ppm. A minimum hydration treatment time period necessary to reduce the presence of such leachable substances to 300 ppm or less in specific lenses can be determined by the periodic measurements. In additional embodiments, other leachable substances, such as, for example, D30 or other diluents, can be measured to detect the presence of a maximum amount of approximately 60 ppm. Embodiments can also include setting a threshold amount of a particular leachable substance at the minimum detection level ascertainable by the testing equipment.
Examples of leaching aids, according to the present invention include, without limitations, alkanes, ketones (e.g. 2-butanone), amides, ethers (e.g. THF), alcohols (e.g. methanol), esters (e.g. ethyl acetate), aldehydes, nitrogen-containing cyclic compounds, toluene, water, ethoxylated alcohols or ethoxylated carboxylic acids, ethoxylated glucosides or sugars, optionally with attached C₆-C₁₄carbon chains, polyalkylene oxides, sulfates, carboxylates or amine oxides of C₆-C₁₄compounds. Examples include cocamidopropylamine oxide, C₆-C₁₄fatty alcohol ethoxylated with ethylene oxides, sodium dodecyl sulfate, polyoxyethylene-2-ethyl hexyl ether, polypropylene glycol, polyethylene glycol monomethyl ether, ethoxylated methyl glucoside dioleate, and the sodium salt of n-octylsulfate, sodium salt of ethylhexyl sulfate.
By way of non-limiting examples, various implementations can include release and removal of leachable impurities that is accomplished by way of a batch process wherein devices are submerged in a solution contained in a fixed tank for a specified period of time or in a vertical process where devices are exposed to a continuous flow of a solution that includes at least one of a leach aid. In some embodiments, the solution can be heated with a heat exchanger or other heating apparatus to further facilitate leaching of the device. For example, heating can include raising the temperature of an aqueous or organic solution to the boiling point while a device is submerged in the heated solution. Other embodiments can include controlled cycling of the temperature of the solution. Some embodiments can also include the application of physical agitation to facilitate leach. For example, a strainer container holding the device can be vibrated or caused to move back and forth within a leaching solution. Other embodiments may include ultrasonic waves through the solution.
The choice of a leaching aid or solvent depends on the impurities present in the composition. Each solvent has a capability of extracting certain impurities with an overlapping range of chemical efficiency. For example, 2-butanone, THF, methanol and ethyl acetate are used sequentially on a same set of fully cured devices; which helps in removing all identified impurities step by step. Water miscible solvents are kept for last. A continuous soxhlet extraction may be employed which utilizes fresh solvent each time. Each soxhlet extracting phase may be sized to hold 500 lenses of 20 diopter. Maximum quantity varies with the power for given sized extractor. However extractors can be easily scaled up to meet the quantity requirement. Flow rate for the solvent varies according to extractor and according to cycle time. A holding time of 3 hours is kept for each solvent. For example, a drop rate of 100 ml/hr is kept for 300 ml extractor.
For example, freshly cured multifocal ophthalmic devices, prepared from the co-polymeric composition presented herein are kept in glass thimble, which is soaked in a bath of one leaching aid solution, and then exchanges its position to a bath holding the next solvent and so on; wherein each soak is maintained for 15-30 minutes. A vacuum tempering is performed thereafter in order to dry the devices at 110° C. and 0.1 mbar.
According to some embodiments of the present invention, post operation of reducing tack may be performed on a anterior surface or on both surface by processing lens by methods such as plasma treatment, surface fluorination, bulk fluorination, hydrophilic coating, irradiating with EB rays, high energy UV rays or by other energy intensive rays, use of internal wetting agents for selective migration and allied.
It should be noted herein that according to some embodiments of the present invention, the composition presented herein can be used to manufacture ophthalmic devices as described herein which are used also for drug delivery. In these embodiments, the non-leachability of the main additives and components (such as, for example, the curcuminoid compound discussed hereinbelow) is in effect, however, the drug which is delivered from the device to the surrounding tissue is in fact leachable, and can diffuse from the matrix (typically a hydrogel) to the physiological medium in which the device is situated and from there to the tissue to be treated.
An ophthalmic or ocular device, typically a lens, and particularly the lens body of a multifocal ophthalmic device as presented hereinabove, formed from the composition presented herein, can be manufactured by using one or two basic methods: molding into a final form without further machining, and shaping and molding followed by machining for reshaping and polishing. Hence, a device as described herein, made from a polymeric or co-polymeric composition as presented herein, can be made while preparing the polymeric or co-polymeric composition, or prepared from a pre-formed polymeric or co-polymeric composition.
For example, multi-part molds can be used to fashion the composition presented hereinbelow into a useful article of a complex shape, such as the lens body of the multifocal ophthalmic device presented hereinabove or any ophthalmic lens. In the case of the lens body of a multifocal ophthalmic device as presented herein, the multi-part molds can include for example, a first mold part with a convex or concave surface that corresponds to a back curve of an ophthalmic lens, and a second mold portion with a generally convex surface that corresponds to the complex structure of the front curve of the multifocal lens, which includes an inverse form of the plurality of concentric annular zones separated by slanted steps, as described herein. To prepare a lens using such mold portions, the uncured lens' composition is placed between the mold portions and subsequently cured. The lens' composition may then be cured, for example by exposure to either or both heat and light. The cured composition forms a lens body according to the dimensions and features of the mold portions. Following curing, traditional practice dictates that the mold portions are separated and the lens remains adhered to one of the mold portions, calling for a release process to detach the lens from the remaining mold part. In some embodiments, the process of manufacturing the lens body, the cured lens body having the plurality of concentric annular zones separated by slanted steps may be subjected to further polishing and/or shaping to achieve final desired form.
The formation of the ophthalmic device from a polymeric or co-polymeric composition as presented herein can also be effected by, for example, a computer-controllable manufacturing device. For example, the lens body of the multifocal ophthalmic device presented herein may be shaped into final form in two basic steps, wherein in the first step the crude lens is forged from the co-polymeric composition presented herein, and in the second step the plurality of concentric annular zones separated by slanted steps, as described herein, are formed in the cured crude lens body using a computer controllable manufacturing device.
A “computer controllable manufacturing device” refers to a device that can be controlled by a computer system and that is capable of producing directly a lens body or a mold for producing an ophthalmic device. Any known, suitable computer controllable manufacturing device can be used in the invention. Exemplary computer controllable manufacturing devices include, but are not limited to, lathes, grinding and milling machines, molding equipment, and lasers. In various exemplary embodiments of the invention a Computerized Numeric Controlled (CNC) lathe machine can be used, such as the lathers marketed under the trade names DAC™ Vision, Optoform and CareTec.
Additional features of the ophthalmic device, co-polymeric composition and/or polymeric or co-polymeric composition incorporating a curcuminoid therein are described in International Patent Application No. IB2010/053818 and in Indian Patent Application Nos. 1938/MUM/2010 and 2888/Mum/2010, the teachings of which are incorporated by reference as if fully set forth herein.
It is expected that during the life of a patent maturing from this application many relevant refractive-diffractive hydrophobic ophthalmic devices will be developed and the scope of the term refractive-diffractive hydrophobic ophthalmic devices is intended to include all such new technologies a priori.
As used herein the term “about” refers to ±10%.
The terms “comprises”, “comprising”, “includes”, “including”, “having” and their conjugates mean “including but not limited to”.
The term “consisting of” means “including and limited to”.
The term “consisting essentially of” means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure.
The word “exemplary” is used herein to mean “serving as an example, instance or illustration”. Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments.
The word “optionally” is used herein to mean “is provided in some embodiments and not provided in other embodiments”. Any particular embodiment of the invention may include a plurality of “optional” features unless such features conflict.
As used herein, the singular form “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a compound” or “at least one compound” may include a plurality of compounds, including mixtures thereof.
Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.
Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.
As used herein the term “method” refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the chemical, pharmacological, biological, biochemical and medical arts.
It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.
Various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below find experimental support in the following examples.

EXAMPLES

Reference is now made to the following example, which together with the above descriptions illustrates some embodiments of the invention in a non limiting fashion.

Example 1

A Multifocal Lens Device

A prototype multifocal lens device was designed according to various exemplary embodiments of the present invention. The lens device included 30 zones and steps. FIG. 5A illustrates the central (innermost) zone (referred to as zone 1), and FIG. 5B illustrates the peripheral (outermost) zone (referred to as zone 30). As shown, zone 1 has a step height H=1.83 microns and slope s=84°, and zone 30 has a step height H=0.09 microns and slope s=25°. Both zones exhibit diffractive for near vision and refractive power for far vision.
The values of step height H, step slope s and step width W_sfor each of the 30 steps is summarized in Table 1, below.

TABLE 1

	Step height	Step slope	Step width
Zone No.	[μm]	[degrees]	[μm]

1	1.83	84	0.19
2	1.77	84	0.19
3	1.71	84	0.18
4	1.64	83	0.19
5	1.57	83	0.19
6	1.51	83	0.19
7	1.45	83	0.19
8	1.40	83	0.18
9	1.32	82	0.18
10	1.26	81	0.19
11	1.19	81	0.18
12	1.16	81	0.19
13	1.09	80	0.19
14	1.01	80	0.18
15	0.94	79	0.19
16	0.90	79	0.18
17	0.90	79	0.18
18	0.82	77	0.19
19	0.77	76	0.19
20	0.70	75	0.19
21	0.64	73	0.19
22	0.60	72	0.19
23	0.51	70	0.19
24	0.46	68	0.19
25	0.41	65	0.19
26	0.36	62	0.19
27	0.30	58	0.19
28	0.20	46	0.19
29	0.14	36	0.19
30	0.09	25	0.19

Example 2

Co-Polymeric Composition—Materials and Methods

2-phenoxyethyl acrylate (POEA) was obtained from Sigma-Aldrich, India, and used as an exemplary aromatic monomer characterized as forming a homopolymer having a refractive index of that ranges from 1.50 to 1.53 (first aromatic acrylate monomer).
2-phenylethyl acrylate (PEA) was obtained from Polysciences Inc., and used as an exemplary aromatic monomer characterized as forming a homopolymer having a Tg lower by 2-30° C. than a Tg of the homopolymer of POEA (second aromatic acrylate monomer).
2-methoxyethyl methacrylate (MOEMA) was obtained from Sigma-Aldrich, India, and used as an exemplary monomer characterized as forming a homopolymer having a Tg lower than 35° C. (third monomer).
The above monomers were used after high vacuum distillation for removal of polymerization inhibitors and impurities such as corresponding alcohols and acid.
2-hydroxyethyl methacrylate (HEMA) was obtained from Sigma Aldrich, India, and used as is, as an exemplary monomer characterized as forming a homopolymer which is capable of absorbing water to at least 20% of its total weight (fourth monomer).
1,4-butane diol diacrylate (BDDA) was obtained from Sartomer, Asia, and used as is, as an exemplary crosslinking monomer. The incorporation of a crosslinking monomer depends on the intended/desired unfolding time, flexibility, loop pull force and compression force. This exemplary crosslinking monomer is being selected as suitable in the development of an IOL which requires a short unfolding time of less than or equal to 5 seconds (fifth monomer).
2,2′-azobis-(2,4-dimethylvaleronitrile) (AIVN) was obtained from HPL Polymer Additives, India, and used as is, as an exemplary initiator.
2-(5-chloro-2H-benzotriazole-2-yl)-6-(1,1-dimethylethyl)-4-methyl-phenol (TINUVIN® 326) was obtained from Ciba Specialty Chemicals, India, and used as is, as an exemplary UV absorber of the hydroxyphenylbenzotriazole class. 4-[(E)-phenyldiazenyl]-phenyl-2-methacrylate was synthesized in the inventor's laboratory, and used as an exemplary yellow dye.
Refractive Index:
The refractive index of some exemplary polymeric compositions presented hereinbelow was determined following the ASTM D542-2000 standard using an Abbe refractometer prisms system (ATAGO U.S.A., Inc, Model DR-A1).
Tested specimens are cut to blocks of 1 mm thickness, 10 mm width and 50 mm length. The blocks are fitted on the face of the fixed half of the refractometer prisms system. Both surfaces are polished to the extent that sharply defined straight dividing line is seen. Three specimens are prepared for each batch of polymeric composition. Conditioning is done at 23±2° C. and 50±5% relative humidity for no less than 40 hours prior to test, and the test is conducted at same conditions.
Mechanical Strength:
The mechanical strength (also referred to herein interchangeably as the “loop pull force”) of some exemplary polymeric compositions presented hereinbelow was determined following the ISO 11979-3:2006 standard using a standard tensometer (Universal Testing Machine, Lloyd's LF plus with 10N load cell).
Lenses prepared from polymeric compositions according to some embodiments of the present invention, were conditioned at 23±2° C. and 50±5% relative humidity for not less than 40 hours prior to testing, and the tests were conducted at same conditions.
The lenses were clamped so that the direction of the pull was tangential to the loop at the loop/optic junction in the tensometer. The extension rate was set at 1 mm/minute and the tensometer was activated. The lens was pulled until the loop broke or separates from the lens and the Young's modulus value recorded.
Glass Transition Temperature (Tg):
The glass transition temperature of some exemplary polymeric compositions presented hereinbelow was determined following the ASTM D3418-03:2000 standard using a differential Scanning colorimeter (Shimadzu Scientific Instruments, Model DSC 60A).
Polymeric composition specimens' mass was 15 mg. Helium was purged during weighing and testing, ad the weighing was performed at an accuracy of ±10 μg.
A preliminary thermal cycle was performed and recorded by cooling the sample at a rate of 20° C. per minute from at least 37° C. to −50° C. The temperature was maintained for five minutes at 37° C. and thereafter quenched to −50° C. and maintained at that for five minutes. This cooling cycle was repeated at a rate of 20° C. per minute and the cooling curve was recorded until distinct lineaments of glass transition temperature have been completed.
Shore a Hardness: The Shore A hardness of some exemplary polymeric compositions presented hereinbelow was determined following the ASTM D2240:2000 standard using a digital Shore A hardness meter (Mitutoyo America Corporation, Model HH-336-01).
Digital Shore A hardness meter was attached to a constant pressure hardness measurement stand. A sample of a polymeric composition, according to some embodiments of the present invention, was placed exactly within the shaped cavity, and a side lever was pressed until the reading of the pressure gauge was constant, and the Shore A hardness value was recorded.
Visible Light Transmission:
The visible light transmission of some exemplary polymeric compositions presented hereinbelow was determined following the ASTM D 1003 standard and using a visible light spectrophotometer (Varian, Inc., Model Cary 50).
Samples of the polymeric composition according to some embodiments of the present invention, were cut to blocks of 1 mm thickness, 10 mm width and 50 mm in length so as to fit into the polished face of a quartz cuvette. Both surfaces of the sample were polished to the extent that no gap is seen between the cuvette surface and sample. Such highly polished surface, typically to an IOL, is needed to minimize the losses due to air interface scattering. Three samples were prepared from each preparation batch, and conditioned at 23±2° C. and 50±5% relative humidity for at least 40 hours prior to testing, and testing was conducted at same conditions.
The spectrum of the test was set from 250 nm to 800 nm in UV-Vis spectrophotometer panel, and the sample was scanned through the whole spectrum of wavelengths while recording the transmission results.
Unfolding Time:
The unfolding time of the finished lens product, prepared from polymeric compositions according to some embodiments of the present invention, was determined using an injector, a cartridge and a stopwatch.
A 1.85 mm diameter sterile cartridge was filled with Visco elastic (Viscolon) solution or another suitable delivery medium, and the tested lens was placed in by means of forceps. The lens was put into the cartridge folded while letting the interior surfaces come in contact. The cartridge was loaded into the injector, and excess Viscolon was forced out of the cartridge. The injector plunger was pressed smoothly so as to force the lens comes out of the cartridge onto a Petri dish which filled with 0.9% saline at 25° C.
The exact time interval for unfolding was recorded with a precise stop watch, started from the point when the lens comes out of cartridge and up to the point when it is completely relaxed in the saline and unfolds fully, and this time interval was defined as the unfolding time for a particular lens sample.
Glistening Test:
The glistening of the finished lens product, prepared from polymeric compositions according to some embodiments of the present invention, was determined using a microscope.
The lens was immersed in physiological medium such as 0.9% saline solution, and kept at 40° C. in forced air circulatory oven for 72 hours. The lens was thereafter cooled while immersed in the saline for a period of 3 hours, and thereafter observed under a 50× microscope for examination for vacuoles and glistening.
Extractables and Leachables Content:
The extractables and leachables content (also referred to herein as the leachable content) in samples of the polymeric composition according to some embodiments of the present invention, was determined following the ISO 11979-5:2006 and ISO 11979-5:2006 standards and using standard gravimetric analysis.
A number of exemplary lenses were dried under vacuum at 60° C.±5° C. for three hours, and thereafter allowed to cool to room temperature under vacuum before weighing. The lenses were weighed to the nearest 0.1 mg and placed in an extraction thimble. Boiling stones were placed in the flask, and the flask was filled to about 50% of its capacity (about 250 ml) with THF.
The extraction thimble was placed in a Soxhlet apparatus fitted with the flask and a condenser. The flask was heated with a mantle and while chilled water was circulated through the condenser. The extraction rate was set at about 4 thimble flushes per hour and the lenses were extract for 3 hours.
At the end of the extraction cycle the solvent was allowed to cool to room temperature and the thimble with the lenses was removed from extractor. The lenses were put in a Petri dish under laminar flow, and carefully separated from each using PTFE coated forceps. The extracted lenses were dried to constant mass in a vacuum oven.
The total weight of the dried lenses was determined after the first extraction cycle and the change in weight effected by the extraction was recorded.
The procedure was repeated with methyl ethyl ketone and methanol respectively with new thimbles.
Dioptric Power:
The resulting dioptric power was compared to the expected dioptric power following the ISO 11979-2:1999 standard and using a standard dioptric power measuring device (ROTLEX Ltd., Israel, Model IOLA Plus).
The expected dioptric power was determined using dimensionally details pertaining to the casting halves of the mold. Such a test can identify uneven or greater shrinkage in the cast which may lead to unacceptable optic parameters or variation in the dioptric power, leading to disqualification of a lens product. A process of extraction mainly contributes to the uneven shrinkage.
The pre-polymerization mixture of the polymeric composition according to some embodiments of the present invention, was cast in mold halves and processed subsequently to form an IOL.
The power of the lens was measured at the end of process and recorded together with the difference in the expected dioptric power.
Tackiness:
The tackiness of the finished lens product was determined following ASTM D 3654 standard and using a standard tensometer (Universal Testing Machine, Lloyd's LF plus with 10N load cell).
A tested polymeric composition was formed and cast as a lens but in a form of strips having dimension 50 mm in length, 10 mm in width and 1 mm in thickness.
Posterior surface of two strips were faced towards each other and pressed by 200 gm weight for 24 hour at 25° C., thereby forming a single lap shear joint. 10 mm edges were left unattached at either end of the strips intentionally. These ends were used for gripping in a fixture attached to universal testing machine (mechanical testing machine).
Thereafter the joint strips were vertically aligned and stretched at constant rate of elongation of 2 mm per minute.
A peak force reading point of break was recorded. This was determined as the shear force required to separate the joint strips which, and assign as the measure of tackiness or self adhesion integrity.
Modular Transfer Function:
The modular transfer function (MTF) of some exemplary polymeric compositions presented hereinbelow was determined following the ISO 11979-2:1999 standard and using a standard model eye (ROTLEX Ltd., Israel, Model IOLA Plus).
Samples of IOL, prepared from the polymeric composition according to some embodiments of the present invention, was placed in cuvette filled with saline and a converging beam from the model cornea exposed the central circular 3.00 mm±0.1 mm of the lens. The difference in refractive index between the lens and the liquid medium was recorded within 0.005 units of that under in situ conditions.
The lens front surface was placed at a plane between 27 mm to 28 mm in front of the focal point of the model cornea itself, taking refractive index of the image space to be 1.336. The light source was by filtration or otherwise confined to 546 nm±10 nm.
The procedure was performed while ensuring that the lens is in the correct position, and that the whole unit is well aligned with the optical axis of the bench, and focused to obtain maximum MTF at 100 lines per millimeter while recording the MTF value.

Example 3

Polymerization Mixture and Reaction

Following are formulations and a process for forming an exemplary polymeric compositions, according to some embodiments of the present invention.
General Procedure:
Prior to weighing, all monomers are degassed for 30 minutes in a degasser operating at 50 mm Hg vacuum.
All monomers, initiator, UV absorber and yellow dye are mixed in a reaction kettle at room temperature until the liquid mixture becomes homogenous and clear.
After blending, nitrogen is purged for 15 minutes by bubbling though the mixture, and the mixture is added to a stirred autoclave reactor and heated to 40° C. while stirring with a three-blade propeller under a 2 Kg nitrogen pressure.
When the amount of unreacted volatile matter drop below 30% w/w and the viscosity reach 120±10 cps at 25° C., the reaction mixture is cooled to −30° C. in an oil bath, and thereafter is allowed to warm up to room temperature.
Thereafter additional initiator is added to the reaction mixture while mixing the mixture until all the initiator is fully dissolved.
Preparation of an Exemplary Composition:
Exemplary co-polymeric composition, denoted Ex. 0 hereinafter, was prepared as follows.
Prior to weighing, all monomers were degassed for 30 minutes in a degasser operating at 50 mm Hg vacuum. The exemplary formulation presented below represents a batch size of 600 grams.
342 grams of 2-phenoxyethyl acrylate, 102 gm of 2-phenyl ethyl acrylate, 90 grams of 2-methoxyethyl methacrylate, 54 grams of 2-hydropxy ethyl methacrylate, 12 grams of 1,4-butane diol diacrylate, 0.3 grams of 2,2′-azobis(2,4-dimethylvaleronitrile), 1.2 grams of TINUVIN® 326 (benzotriazole UV absorber) and 0.72 grams of 4-[(E)-phenyldiazenyl]-phenyl-2-methacrylate (yellow dye) were added to a 1 liter reaction kettle, and mixed at room temperature until the liquid mixture became homogenous and clear.
After blending, nitrogen was purged for 15 minutes by bubbling though the mixture, and the mixture was added through an addition funnel to a stirred autoclave reactor and was heated to 40° C. while stirring with a three-blade propeller under a 2 Kg nitrogen pressure. The solution became gradually viscous while monomer entities turn to high molecular weight chains.
When the amount of volatile matter, mainly unreacted monomer entities and short oligomers, had dropped below 30% w/w, as required by the ASTM D 1353-09 standard, and the viscosity has reached 120±10 cps at 25° C., as determined by measuring torque experienced by stirrer shaft connected to constant RPM motor, the reaction mixture was cooled to −30° C. in an oil bath, and thereafter allowed to warm up to room temperature.
Thereafter 1.2 grams of the initiator 2,2′-azobis(2,4-dimethylvaleronitrile) were added to the reaction mixture while mixing the mixture until all the initiator was dissolved therein.
The above exemplary polymeric composition, referred to herein as “Ex. 0”, was prepared from the exemplary formulation presented above, having the following proportions:
POEA—56%;
PEA—17%;
MOEMA—15%;
HEMA—9%;
BDDA—2%;
AIVN—0.05% initial aliquot plus 0.2% second aliquot;
UV absorber—0.2%; and
Yellow Dye—0.12%.
The final homogenous mixture of Ex. 0 was filtered through 0.2 micron PTFE membrane disc filter and placed into a dosing pump.

Example 4

Intraocular Lens Product Molding and Post-Molding Workup

The polymerization mixture was prepared as described hereinabove, a curing agent was added thereto and the mixture was dispensed into intraocular lens polypropylene mold halves.
The mixture was cured in a temperature cycle of 40° C. for 12 hours; 45° C. for 6 hours; and 50° C. for 6 hours.
As discussed hereinabove, intraocular lenses, prepared as described hereinabove, may contain impurities such as un-reacted monomers, crosslinker, initiator and other residues, which may leach out into the physiological aqueous media once implanted in the eye. In order to cleanse the product, a multi-solvent extraction procedure was used to remove these impurities as described below.
About 30 intraocular lenses were placed in an immersible lens mount fitted to a 60 ml extractor vessel (obtained from Sigma Aldrich, India). The extractor vessel was filled with an alcohol such as isopropanol, and the lenses were kept therein under reflux temperature for 9 hours. This procedure was repeated using a ketone such as acetone. Thereafter the lenses were dried in a vacuum oven at 10 mm of Hg and 110° C.
After drying, the cleansed lenses were treated with EB rays (electron beam) to quench unreacted monomers and reduce tack on the interior and exterior surfaces.

Example 5

Additional Formulations

Lens products made from other exemplary formulations for polymeric compositions, according to some embodiments of the present invention, were prepared by following the aforementioned procedures for preparation of the pre-polymerization mixture, polymerization reaction, molding and post-molding workup.
Table 2 presents additional exemplary formulations for polymeric compositions according to some embodiments of the present invention, wherein the resulting compositions are denoted Ex. 1-10, and each component is presented in its relative content in weight percentage of the total weight of the composition.

TABLE 2

							UV	Yellow
Component	POEA	PEA	MOEMA	HEMA	BDDA	AIVN	absorber	Dye

Ex. 0	56	17	15	9	2	0.25	0.2	0.12
Ex. 1	16	57.5	15	8.85	2.65	0.25	0.2	0.01
Ex. 2	67.65	18.82	0	10.41	3.12	0.25	0.2	0.01
Ex. 3	68.5	0	17.85	10.5	3.54	0.25	0.2	0.01
Ex. 4	0	37.65	35.3	20.82	6.23	0.25	0.2	0.01
Ex. 5	63.1	17.55	16.46	0	2.91	0.25	0.2	0.01
Ex. 6	59.06	16.43	15.41	9.1	0	0.25	0.2	0.01
Ex. 7	52.5	16	11	7	2	0.25	0.2	0.06
Ex. 8	54.5	17	12	7.5	2.5	0.25	0.2	0.06
Ex. 9	56.5	18	13	8	3	0.25	0.2	0.06
Ex. 10	58.5	19	14	8.5	3.5	0.25	0.2	0.06

Example 6

Analyses and Characterization of Ophthalmic Co-Polymeric Composition

The resulting lens products, prepared according to the procedure presented hereinabove, were tested for a series of characteristics, and analyzed according to industry-accepted parameters, as presented herein.
Following are the quality test results obtained for exemplary composition Ex. 0 prepared as described in Example 1 hereinabove:
Refractive index: 1.525;
Loop pull Force (mechanical strength): 45 grams;
Glass transition temperature (Tg): 9° C.;
Shore A hardness: 78;
Visible light transmission: more than 98%;
Unfolding time at 25° C. in 0.9% saline: 5 Seconds;
Visual glistening test: Substantially free of glistening and vacuoles;
Percent extractables/leachables: 0.3%
Resulting dioptric power versus expected resultant power: 20D versus 20D;
Tack after EB treatment: tack free; and
Modular transfer function: 0.68.
The characteristics obtained from the aforementioned tests, for exemplary polymeric compositions according to some embodiments of the present invention, and lenses made therefrom, produced as described hereinabove from the aforementioned exemplary polymeric compositions presented in Example 3, Table 2, are presented in Table 3 below.
The test denoted “1” presents the refractive index as measured at 25° C.;
The test denoted “2” presents the vacuoles presence as measured in water at 25° C.;
The test denoted “3” presents the Shore A hardness ratios;
The test denoted “4” presents the visible light transmission, given a positive score when accomplishing less than 1% transmission of visible light at 370 nm, more than 70% transmission at 400 nm, and a 10% cut-off in the wavelength range of 370-380 nm;
The test denoted “5” presents the unfolding time at 25° C. in normal saline through sub 2 mm cartridge.
The test denoted “6” presents the halo's test (internal reflection) results in dry conditions, given a positive score if no internal reflection can be detected;
The test denoted “7” presents the percent of detectable leachables after post-molding operation; and
The test denoted “8” presents the tack feel, given a positive score if no tackiness can be perceived.

	TABLE 3

	TEST No.

	1	2	3	4	5	6	7	8

Ex. 0	1.525	clear	78	+	5	+	0.3	+
Ex. 1	1.5371	clear	76.8	+	2	−	0.62	−
Ex. 2	1.5466	opaque	81.7	+	6	+	0.78	−
Ex. 3	1.5354	hazy	81.8	+	2	+	0.59	−
Ex. 4	1.5069	opaque	85.8	+	2	+	0.47	+
Ex. 5	1.5328	opaque	81.3	+	3	+	0.65	−
Ex. 6	1.5265	translucent	74.8	+	9	+	1.3	−/+
Ex. 7	1.52	clear	80	+	5.14	+	0.42	−/+
Ex. 8	1.522	clear	79.7	+	5.6	+	0.48	−/+
Ex. 9	1.525	clear	78.6	+	4.8	+	0.49	−/+
Ex. 10	1.527	clear	78	+	4.4	+	0.47	−/+

As can be seen in Table 3, the results obtained for the exemplary polymeric compositions according to some embodiments of the present invention, clearly show superior characteristics by industry standards, wherein the polymeric compositions denoted Ex. 0 and 7-10 exhibit optimal performance.

Example 7

Curcumin Sample Preparation

Materials and Experimental Methods:
Silica Gel 60 aluminum plates, and preparative Silica gel 60 extra pure for column chromatography 0.063-0.200 mm (70-230 mesh), were obtained from Merck KGaA, Germany.
A commercially available mixture of curcuminoids (Sigma Aldrich, India; Product number C1386; 70% curcumin purity) was post purified to at least 97% curcumin as follows. Preparative silica gel was used to fill a prefabricated column, and a mixture of curcuminoids (1% concentration in acetone) was loaded and eluted through the column at 25° C. using a mixture of chloroform and ethyl acetate (9:1 ratio).
The solvent was removed by vacuum distillation to afford a residue. The solid residue was dried in a vacuum oven at 50° C. under 0.1 mbar for 3 hours.
Assay and purity of curcumin was conducted by measuring melting point and λmax on UV-Vis spectrophotometer. The melting point of the solid residue was measured at 181° C. (published meting point for curcumin is 182-183° C.), and the λmax was found to be 419 nm (within range 415-420 nm as the published λmax for curcumin at concentration of 10 mg/l in acetone).
FIG. 6 presents the UV-Vis absorption spectra of the sample of curcumin after purification on a preparative silica gel column at 25° C. using a mixture of chloroform and ethyl acetate (9:1 ratio).
The impurities may be attributed to monodemethoxycurcumin, and bisdemethoxycurcumin, whose boiling point and color differs significantly from curcumin (reported boiling point of bisdemethoxycurcumin is 232-233° C.).

Example 8

Transparent Polymeric Object Containing Curcumin

Materials and Experimental Methods:
Dilauroyl peroxide (Cat. No. 34974) was obtained from Acros Organics.
4-[(E)-phenyldiazenyl]phenyl-2-methacrylate (PDPMA) was obtained from local contract laboratories.
The acrylic monomers 2-Phenoxy ethyl methacrylate (POEMA) was obtained from Sartomer Company Inc., Singapore), cyclohexyl acrylate (CHMA) was obtained from Polysciences Inc., USA) and 1,4-butane diol diacrylate (BDDA) was obtained from Sartomer Company Inc., Singapore).
The separated curcumin from the preparative column chromatography procedure described above was weighed into a plastic vial. A solution of monomers containing 65.2% 2-phenoxy ethyl methacrylate (POEMA), 32.8% cyclohexyl acrylate (CHMA) and 2% 1,4-butane diol diacrylate (BDDA) by weight percentages respectively, was prepared and added to the curcumin-containing vial so as to give a curcumin concentration of approximately 0.1%. After dissolving the curcumin into the POEMA/CHMA/BDDA monomer solution, a catalytic amount (0.3%) of dilauroyl peroxide was added to the solution as a polymerization initiator.
Rod-shaped objects of 14 mm in diameter and of 100 mm in length were prepared from the polymeric mixture by placing the curcumin/monomer solution in vials and pressure fitting the closure by keeping the ‘He’ jacket over it. Polymerization was effected by placing the vials into 40° C. oven and curing for 24 hours. The temperature of the oven was raised to 60° C. and the vials were heated for 3 hours to effect the post cure of the rod stock. Circular slices were cut from the rods and subjected to Soxhlet extraction for 3 hours in toluene.
Thereafter the extracted material samples were dried in air followed by drying at about 50° C. under vacuum. The UV/Vis transmission and absorption spectra was measured for the sample slices before and after the Soxhlet extraction and drying.
Extraction is a typical step in IOL manufacturing processes, wherein the matrix is swelled with water to a certain limit (typically lower than 30% by weight) and the extractables are removed by various solvents. Curcuminoid compounds, according to some embodiments of the present invention, are entrapped in the matrix, however, their interaction with acrylic matrix is such that they do not leave the matrix even under extraction conditions.
FIGS. 7A-B present the UV/Vis transmission and absorption spectra as measured from slice samples of the rod-shaped object prepared from the curcumin/POEMA/CHMA/BDDA polymerization mixture, an exemplary composition according to some embodiments of the present invention, after mild washing and drying (FIG. 7A) and after Soxhlet extraction for 3 hours in toluene (FIG. 7B). As can be seen in FIGS. 7A-B, the spectra shows that UV light is blocked and the sample does not transmit UV light in a range of about 180 nm to 380 nm. As can further be seen in FIGS. 7A-B, the UV/VIS transmission and absorption spectra of the samples before and after Soxhlet extraction is remarkably similar, indicating no measurable leakage of curcumin from the sample during extraction.
These results affirm that curcumin is an effective UV stabilizing compound in a polymeric matrix. UVB and UVC light rays are substantially blocked up to 390 nm with transmittance of less than 50% (λ=392.5 nm; % T=49.65%) with about 0.025 percent by weight of curcumin from the total weight of the sample. The comparative spectra before and after Soxhlet extraction affirm that curcumin is an effective UV stabilizer as an entrapped species in an acrylic matrix, exhibiting no tendency of leaching out of the acrylic matrix even when it is subjected to the exhaustive extraction (transmittance at λ=378.5 nm is 45.918% before extraction, and 43.825% after extraction).

Example 9

UV-Blocking Strength Comparison

In order to evaluate the UV/Vis interaction attributes of the curcumin-doped transparent object, prepared as described hereinabove, these properties were compared with those obtained from a transparent object prepared with 4-[(E)-phenyldiazenyl]phenyl-2-methacrylate (PDPMA), a commercially available diphenyl azo compound. Curcumin and PDPMA were used at a concentration of 0.005 wt % and 0.25 wt % respectively.
A solution of monomers containing 65.2% POEMA, 32.8% CHMA and 2% BDDA (1,4-butane diol diacrylate) by weight respectively, was mixed to give the aforementioned test compound concentration. Thereafter, dilauroyl peroxide (0.3%) was added as a polymerization initiator.
Rod-shaped objects having 14 mm in diameter and of 100 mm in length were prepared as described hereinabove. Circular slices were cut from the rods and Soxhlet-extracted for 3 hours in toluene. Following the extraction, the material samples were dried in air followed by drying at about 50° C. under vacuum.
The dye's strength can be assessed by comparing transmittance values at various wavelengths in the visible blue light region of 400-500 nm (unlike curcumin, no commercially available synthetic yellow dye absorbs in UV region). FIGS. 8A-D present the UV/Vis transmission and absorption spectra, measured after Soxhlet extraction and drying, obtained from transparent slices having curcumin at a final content of 0.005 weight percents (FIG. 8A), PDPMA at a final content of 0.005 weight percents (FIG. 8B), curcumin at a final content of 0.025 weight percents (FIG. 8C), and PDPMA at a final content of 0.025 weight percents (FIG. 8D).
As can be seen in FIGS. 8A-D, the UV-blocking strength of the transparent slices having curcumin as a UV-blocker additive, as estimated and compared by their transmission values at wavelengths in the visible blue light region (400-500 nm), are far more intensive than those having PDPMA. Specifically, transmittance at λ=430 nm is about 60% FIG. 8C, about 85% in FIG. 8D, indicating more synthetic dye amount is needed to partly block the visible blue light.
Hence, curcumin is a yellow dye exhibiting dual function by acting as a UV absorber and visible blue light blocker.

Example 10

UV-Blocker Strength Stability

Lens of 20 diopter with center thickness of 0.75 mm, optic diameter of 6 mm and an overall length of 12.5 mm were prepared from a solution of monomers containing 65.2% POEMA, 32.8% CHMA and 2% BDDA (1,4-butane diol diacrylate) by weight.
The tested curcuminoid compound was added to the monomers mixture to a final concentration of 0.025% w/w and 0.05% w/w, and thereafter dilauroyl peroxide (0.3%) was added as a polymerization initiator.
This pre-polymerization mixture was loaded into two PP mold halves and cured in an oven at 80° C. for 26 hours. Thereafter the molds were kept in a vacuum oven at 110° C. for 3 hours.
After curing, the cast product in the form of a thin circular disc was milled to the above mentioned dimensions and subjected to extraction treatment.
The amount of absorbance between 280-500 nm lost after Soxhlet extraction was used as an indication of the amount of curcumin removed from the lens material by the Soxhlet extraction process.
FIGS. 9A-D present the UV/Vis absorption spectra, as collected from lens before extraction prepared with curcumin at 0.025 weight percentage (FIG. 9A), from the same lens after extraction (FIG. 9B), from lens before extraction prepared with curcumin at 0.05 weight percentage (FIG. 9C), and from the latter lens after extraction (FIG. 9D).
As can be seen in FIGS. 9A-D, the low decrease in absorbance at wavelength range between 280 nm to 500 nm indicated that very small amount of curcumin leach out of the lens during exhaustive solvent extraction. Apart from UV blocking, it is evident that curcumin remains entrapped in the acrylic matrix in spite of subjecting the lens to intense extracting conditions.
Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.
All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.

Claims

What is claimed is:

1. A multifocal ophthalmic device comprising a lens body being formed with a plurality of concentric annular zones separated by slanted steps, wherein said concentric zones effect both diffraction and refraction of incident light, while said steps are substantially devoid of any diffractive or refractive power, said lens body comprises a polymeric or co-polymeric composition derived from a pre-polymerization mixture of monomers which comprises less than 75% of aromatic acrylate monomers.

2. The device of claim 1, wherein at least one curcuminoid compound is incorporated in or on said polymeric or co-polymeric composition and/or said lens body.

3. The device of claim 2, wherein a concentration of said curcuminoid compound ranges from 0.0002 weight percentage to 1 weight percentage of the total weight of the composition.

4. The device of claim 1, wherein said polymeric or co-polymeric composition is derived from a pre-polymerization mixture of monomers which comprises at least 50 weight percent acrylate monomers.

5. The device of claim 1, wherein said co-polymeric composition comprises a polymeric backbone composed of a plurality of backbone units covalently linked to one another, said backbone units being derived from a pre-polymerization mixture of monomers which comprises:

a first aromatic acrylate monomer, characterized as forming a first homopolymer having a refractive index that ranges from 1.50 to 1.53; and

a second aromatic acrylate monomer, characterized as forming a second homopolymer having a Tg lower by a range of 2° C. to 30° C. than a Tg of said first homopolymer;

wherein:

a concentration of said first aromatic acrylate monomer ranges from 50% to 60% of the total weight of the composition; and

a concentration of said second aromatic acrylate monomer ranges from 15% to 20% of the total weight of the composition.

6. The device of claim 5, wherein said pre-polymerization mixture further comprises:

a third monomer, characterized as forming a third homopolymer having a Tg lower than 35° C.;

a fourth monomer, characterized as forming a fourth homopolymer which is capable of absorbing water to at least 20% of the total weight of said fourth homopolymer; and

a fifth monomer, being a crosslinking monomer,

wherein:

a concentration of said third monomer ranges from 10% to 15% of the total weight of the composition;

a concentration of said fourth monomer ranges from 5% to 10% of the total weight of the composition; and

a concentration of said fifth monomer ranges from 2% to 5% of the total weight of the composition.

7. The device of claim 1, wherein said lens body has an aspheric profile.

8. The device of claim 7, wherein said aspheric profile is characterized by a conic constant in a range of from about −1.0 to about −3.0, inclusive.

9. The device of claim 1, wherein each step of said steps has a width which is from about 0.17 microns to about 0.2 microns.

10. The device of claim 1, wherein said heights vary from about 1.83 micron at said center to about 0.09 micron at said edge.

11. The device of claim 1, wherein said slopes vary from about 84° at said center to about 25° at said edge.

12. The device of claim 5, having a refractive index of at least 1.53.

13. The device of claim 5, characterized by a glass transition temperature not higher than 5° C.

14. The device of claim 1, being substantially transparent to light at a wavelength ranging from about 400 to about 800 nm.

15. The device of claim 1, being substantially opaque to light at a wavelength ranging from about 190 to about 440.

16. The device of claim 1, being selected from the group consisting of a contact lens and an implantable ocular device.

17. The device of claim 1, suitable for use as an optical distortion corrective device, a retinopathy corrective device, a retinal detachment corrective device, an occlusion corrective device, a proliferative retinopathy corrective device, a proliferative vitreoretinopathy corrective device, a diabetic retinopathy corrective device, a degenerative disease corrective device and an age-related macular degeneration corrective device.

18. A method of treating a medical, ophthalmologic and/or esthetic condition associated with an eye of a subject in need thereof, comprising implanting the multifocal ophthalmic device of claim 1 in an eye of the subject, thereby treating the condition.

19. The method of claim 18, wherein said condition is selected from the group consisting of an optical distortion, optical corrective treatment, retinopathy, retinal detachment, occlusion, proliferative retinopathy, proliferative vitreoretinopathy, diabetic retinopathy, degenerative disease and an age-related macular degeneration.