WO2007128923A2

WO2007128923A2 - Method for the preparation of a biocompatible gel with controlled release of one or more active ingredients with low solubility in water, gels thus obtained and their use

Info

Publication number: WO2007128923A2
Application number: PCT/FR2007/000781
Authority: WO
Inventors: Laurence Hermitte; Samuel Gavard Molliard
Original assignee: Anteis Sa
Priority date: 2006-05-05
Filing date: 2007-05-07
Publication date: 2007-11-15
Also published as: FR2900575B1; FR2900575A1; WO2007128923A3

Abstract

This invention concerns a process for the preparation of a biocompatible gel with controlled release of one or more active lipophilic and/or amphiphilic ingredients comprising a matrix based on one or several biopolymers with or without a functional group, in which in a first step, the lipophilic and/or amphiphilic active ingredient(s) are mixed in a homogenous manner, by dissolution in biocompatible alcohol or a mixture of biocompatible alcohols; in a second step, the homogenous mixture obtained in the first step is mixed with a biocompatible gel comprising a matrix made of one or several biopolymers with or without a functional group. Also described are gels obtained by the method of the present invention and their use in cosmetic and therapeutic fields.

Description

PROCESS FOR THE PREPARATION OF A BIOCOMPATIBLE GEL WITH CONTROLLED RELEASE OF ONE OR MORE ACTIVE SUBSTANCES THAT ARE SOLUBLE IN WATER, GELS THUS OBTAINED AND THEIR USE

The present invention relates to a process for preparing a biocompatible gel with controlled release of one or more active ingredients, the gel thus obtained, as well as its use in the therapeutic and aesthetic field.

Biocompatible gels based on biopolymers, also called polymers of natural origin, such as collagen, hyaluronic acid, or cellulose derivatives have many outlets, whether in the case of therapeutic applications or for cosmetic purposes .

They are especially used for augmentation, tissue separation or supplementation. The fields of application are varied and well known to those skilled in the art: for example as tissue separation materials in general surgery, urology or as a filling material in reconstructive surgery, dental surgery, ophthalmology, or in orthopedics. In dermatology and aesthetic medicine, this solution is used in particular for filling wrinkles, remodeling the face, increasing the volume of the lips or the rejuvenation of the skin of the face. A biologically degradable material designates an optionally functionalized polymer, which will be gradually absorbed by the organism into which it has been injected or implanted (by incision), via the natural mechanisms of elimination (mechanical, chemical and biochemical reactions induced by this organism) . Moreover, it is perfectly tolerated by the cells of the host organism after its injection / implantation and does not cause any undesirable effects because it is not recognized as a foreign body.

According to the prior art, it is possible, either in order to delay the degradation of the matrix (or gel), or to allow controlled release of an active ingredient, to introduce various ingredients into a matrix. .

A matrix according to the present invention refers to a gel consisting of one or more polymers of natural origin functionalized or not functionalized. This gel can be functionalized by grafting or by crosslinking according to techniques well known to those skilled in the art, (see, for example, US Pat. EP0272300, EP1611160, EP0408731).

However, it is also possible to envisage a doubly functionalized matrix, by crosslinking and grafting (see Anteis patent application, PCT / FR / 2004/002052).

Various active principles have already been introduced in matrices based on biopolymers (hereinafter called conventional matrices) with varying degrees of success and according to different methods of administration.

Usually, biocompatible gels used for filling or tissue separation are composed of 80% or more water for injectable forms. In the case of non-injectable gels, such as films, beads or gels more "pasty" (thicker and not injectable by a hypodermic needle), the amount of water is variable depending on the desired product. Gels in injectable form often have a very important hydrophilic character. A hydrophilic substance is any substance that absorbs or has a high affinity for water, or dissolves easily. A substance is said to be hydrophobic or lipophilic when it is soluble in fatty substances, but insoluble in water. An amphiphilic substance has affinity for water and affinity for fatty substances, each of these affinities being variable. Thus, in order to delay the degradation of the matrix by free radicals, a molecule with antioxidant properties can be dispersed therein.

It is known from the state of the art that an anti-radical that integrates easily into a matrix based on biopolymers is vitamin C. This is explained by the fact that this vitamin thanks to its character hydrophilic easily integrates for example within a highly hydrophilic injectable matrix. However, the latter expresses prooxidant properties within such a matrix. Indeed, it itself causes the degradation of said matrix and this rather quickly. The antioxidant properties of vitamin C can not come to combine with the action of the matrix, especially to prevent oxidation of organic macromolecules or to capture free radicals. On the contrary, some molecules, such as vitamin A or vitamin E and Trolox ^® (6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid) are molecules which by their anti-radical capacity can increase the life of said matrix. However, these molecules do not distribute themselves easily within a hydrophilic matrix because of their hydrophobic or amphiphilic nature and the final gel is not homogeneous.

Indeed, vitamin E, which has many advantages (antioxidant action), could be dispersed in a matrix, to be released and to act gradually within the host organism. However, because of its hydrophobic nature, and therefore its low affinity for a hydrophilic matrix, vitamin E, unlike vitamin C, is difficult to incorporate into a hydrophilic matrix. The distribution of the active ingredient resulting from the hydrophobic active ingredient mixture in a hydrophilic matrix will therefore be heterogeneous.

It has thus been found that certain active principles do not integrate homogeneously and / or are not very soluble within a matrix, in particular lipophilic or amphiphilic molecules. Suspensions of active ingredients whose concentration may vary significantly within the matrix are then obtained.

Indeed, many lipophilic or amphiphilic active ingredients, such as Trolox ^® (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) form of "lumps" when they are directly mixed with a matrix of classic type. Thus, these active principles do not integrate homogeneously in a gel when they are mixed directly with said gel.

However, it is essential to obtain a homogeneous gel. It has been observed that many injectable suspensions (eg Kenacort®, Diprostene®) can be injected only after shaking. Now, a homogeneous gel ready for use makes it possible to suppress the stirring of the suspension and thus to reduce the risks associated with poor homogenization of the product to be injected. Both in the case of an injectable gel and an implantable gel, the homogeneity is important for a better control of the concentration and the release profile of the active principles incorporated in said gel. In addition, the homogeneity is important in the case of injectable gel for the act of injection. The gel must be able to eject through a hypodermic needle (for example type 27 G) in an easy manner, in order to inject the gel in a targeted manner. The invention aims to provide a matrix that avoids all or part of the aforementioned drawbacks.

For this purpose, the invention relates to a method for preparing a biocompatible controlled-release gel of one or more lipophilic and / or amphiphilic active principles comprising a matrix based on one or more functionalized or non-functionalized biopolymers, characterized in that

in a first step, the lipophilic and / or amphiphilic active principle (s) are distributed homogeneously, by dissolution, in a biocompatible alcohol or a mixture of biocompatible alcohols

in a second step, the homogeneous mixture obtained in the first step is mixed with a biocompatible gel comprising a matrix of one or more functionalized or nonfunctionalized biopolymers.

The biocompatible gel thus prepared has the advantage of homogeneously containing one or more lipophilic and / or amphiphilic active principles in a hydrophilic matrix according to the prior art (of conventional type). These active principles can be anti-radicals, in particular analogues of. alpha-tocopherol, more particularly Trolox ^® (acid 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) as acid or its derivatives in the form of salts, or anti-inflammatories for example of the family of corticosteroids such as triamcinolone derivatives, and more particularly triamcinolone acetonide (9 alpha-fluoro-11 beta, 21-dihydroxy-16 alpha, 17 alpha-isopropylidenedioxyprene-1,4-diene -3,20-dione). The active principle (s) in question will thus delay the degradation and / or enhance the therapeutic activity of the matrix.

By controlled-release gel, a formulation is defined that makes it possible to modulate the release profile of an active ingredient and possibly to reduce or avoid a "burst" effect.

According to a first embodiment, during the first step, the amphiphilic and / or lipophilic active ingredient (s) are distributed homogeneously, by total dissolution in a biocompatible alcohol or a mixture of biocompatible alcohols.

The total dissolution of an active ingredient corresponds to the dissolution of this active principle in an alcohol or several alcohols. so that the mixture obtained has particles smaller than or equal to 1 micron.

According to a second embodiment, during the first step, the lipophilic and / or amphiphilic active principle (s) are homogeneously distributed, at least partially dissolved and suspended in a biocompatible alcohol or a mixture of biocompatible alcohols.

The partial dissolution of an active ingredient corresponds to the partial dissolution of this active principle in an alcohol or several alcohols so that the mixture obtained has particles greater than 1 micron. This mixture thus obtained forms a suspension.

Advantageously, the biocompatible alcohol is pharmacologically active.

Preferably, the biocompatible alcohol is glycerol and / or propylene glycol and / or polyethylene glycol or a derivative thereof.

Advantageously, the lipophilic and / or amphiphilic active principle (s) used in said process are chosen from: hormones, angiogenic factors, growth factors, genes, anesthetics, anti-mitotics, steroidal anti-inflammatory drugs, anti-radicals, vitamins, anti-histamines or any other pharmacologically active dispersed agents.

Preferably, the lipophilic and / or amphiphilic active principle (s) used in said process are chosen from: antinflammatories of the corticosteroid family, such as (9-alpha-fluoro-11 beta, 21-dihydroxy-16 alpha, 17 alpha- isopropylidene-dioxypregna-1,4-diene-3,20-dione) and / or anti-radicals, such as 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid, vitamin E and pharmaceutically acceptable salts and derivatives thereof.

According to one characteristic of the invention, the biopolymer or biopolymers are chosen from: hyaluronic acid, chondroitin sulfate, keratan, keratan sulfate, heparin, heparan sulfate, cellulose and its derivatives, chitosan, xanthans and alginates, proteins, or nucleic acids and their pharmaceutically acceptable salts and derivatives. Advantageously, the functionalized gel is obtained from crosslinked and / or grafted biopolymers.

The subject of the present invention is also a biocompatible gel with controlled release of one or more lipophilic active principles or amphiphiles, obtained by the preparation process according to one of the above characteristics.

Preferably, the biocompatible alcohol is pharmacologically active. More particularly, the biocompatible alcohol is glycerol and / or propylene glycol and / or polyethylene glycol or a derivative thereof.

Advantageously, the lipophilic or amphiphilic active principle (s) used are chosen from hormones, angiogenic factors, growth factors, genes, anesthetics, anti-mitotics, anti-inflammatory steroids, anti-radicals, vitamins antihistamines, and their pharmaceutically acceptable salts and derivatives.

According to one characteristic of the invention, the lipophilic or amphiphilic active principle (s) used are chosen from the anti-inflammatories of the family of corticosteroids, such as (9-alpha-fluoro-11 beta, 21-dihydroxy-16 alpha, 17 alpha-isopropylidenedioxypengna-1,4-diene-3,20-dione) and / or anti-radicals, such as 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid, or vitamin E, and pharmaceutically acceptable salts and derivatives thereof.

Preferably, the gel has levels of crosslinking with highly crosslinked areas and less or not crosslinked areas, these different levels of crosslinking to obtain controlled release kinetics of active principle (s). Controlled functionalization of the matrix, obtained by crosslinking and / or by grafting, makes it possible to obtain a remanence of the gel and a release of the controlled active ingredient (s), as well as degradation / release profiles that can be adapted according to the target indication. and / or the desired effect. Advantageously, the gel is injectable or implantable.

Preferably, the controlled release gel comprises:

from 0.01 to 100 mg / ml (mass / total volume) of triamcinolone acetonide and / or betamethasone,

-. from 1 to 50 mg / ml (weight / total volume) of glycerol, -. hyaluronic acid with a molecular mass of 0.1 to 100 x

10 ⁶ Da.

Hyaluronic acid concentration of 1 to 50 mg / ml (mass / total volume) More particularly, the controlled release gel comprises:

-. from 1 to 50 mg / ml (mass / volume total) of triamcinolone acetonide and / or betamethasone, -. from 15 to 25 mg / ml (mass / total volume) of glycerol,

-. hyaluronic acid with a molecular mass of 2 to 3 X 10 ⁶ Da.

Hyaluronic acid concentration of 10 to 25 mg / ml (mass / total volume)

Advantageously, the hyaluronic acid is crosslinked using a biepoxide used in an amount of up to 15% (mass / mass)

Preferably, the controlled release gel is applied to separate, replace, fill, or supplement biological tissues. The object of the present invention is also the use of the controlled-release gel according to one of the preceding characteristics, in which the 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid is applied in the field dermatology, ophthalmology or rheumatology, particularly for its anti-radical activities. Preferably, triamcinolone acetonide is applied in the field of rheumatology, ophthalmology or in the treatment of allergic rhinitis.

The subject of the invention is also a controlled-release gel of active principle applied to separate, replace, fill or supplement tissues while diffusing one or more active principles.

The present invention also relates to a method of treatment, characterized in that a controlled release gel according to one of the preceding characteristics, is injected into a biological tissue so as to release a therapeutic substance and / or to separate, replace, fill or supplementing said biological tissue.

Figure 1 is a diagram comparing the anti-inflammatory activity of a formulation containing triamcinolone acetonide according to the invention and other formulations. The combination according to the present invention induces an anti-inflammatory action of longer duration compared to other formulations. The invention will be better understood, and other objects, details, characteristics and advantages thereof will appear more clearly in the following detailed explanatory description of an embodiment of the invention given purely by way of example. illustrative and not limiting.

As indicated above, the biocompatible gel according to the present invention comprises a biocompatible alcohol fraction, the biocompatible alcohol here playing a dual role, that of vector of one or more active ingredients within a gel and pharmacologically active molecule. A vector is a compound that conveys the active principle without however the term vector is used in the targeting sense of a given biological tissue.

It has indeed been found, surprisingly, that the lipophilic or amphiphilic active principles which do not integrate homogeneously into a matrix of conventional type could in certain cases be homogeneously distributed beforehand in a biocompatible alcohol, a homogeneous gel. being subsequently obtained by integrating this premix active ingredients / alcohol biocompatible with said matrix.

These amphiphilic or lipophilic active principles can be all pharmacologically active agents chosen, for example, from hormones, angiogenic factors, growth factors, genes, osteogenic proteins, anesthetics, anti-mitotics, anti-inflammatories, anti-inflammatory drugs, -radicals, vitamins, antihistamines. For example, lipophilic or amphiphilic active ingredients that do not readily integrate homogeneously into a hydrophilic matrix are certain anti-radicals or anti-inflammatories of the corticosteroid family.

It is written in the state of the art that Trolox® is soluble in water. However, after tests performed by the inventor, it has been found that Trolox® is not soluble in water at target concentrations for the desired indications. On the other hand, the inventor surprisingly found that this molecule could be integrated homogeneously into a hydrophilic matrix for therapeutic purposes via, in a first step, dissolution at least partially in a biocompatible alcohol or a mixture of biocompatible alcohols such as glycerol, the undissolved portion forming a homogeneous suspension in this alcohol or mixture of alcohols. The interest of integrating such a molecule into a gel is multiple. Trolox®, an amphiphilic molecule, has properties similar to those of vitamin E. Trolox® is indeed a recognized anti-radical, able to neutralize or reduce the damage caused by free radicals in the body. Its action is therefore important and allows, for example, combined with that of a filling gel or tissue separation, to avoid the oxidation of organic macromolecules by capturing free radicals.

Thus, the integration of such a molecule into a matrix via a biocompatible alcohol has many advantages. The molecule will indeed diffuse from the matrix in order to act on the host organism. The matrix / alcohol / active ingredient system thus offers new therapeutic solutions in many indications, in particular in the following fields: - Dermatology to fight against the aging of the cutaneous tissue thanks to the activity of Trolox® conjugated to that of glycerol in as antiseptic.

- Ophthalmology for cataract surgery or vitreous supplementation. In the present case, the gel of the present invention makes it possible to obtain transparent and "optically homogeneous" gels.

- Or, in the field of rheumatology via intra-articular injections, peri-articular or in the soft parts.

Equally surprisingly, it has been found that anti-inflammatories such as triamcinolone acetonide, which is a hydrophobic substance, is evenly distributed in a biocompatible alcohol, such as glycerol (which is very hydrophilic). It was thus not obvious to those skilled in the art that the hydrophobic present (triamcinolone acetonide) would be uniformly distributed in a very hydrophilic alcohol. Thus, the choice of such a vector in order to introduce said active ingredient in a conventional type of matrix homogeneously, was not obvious. In addition, thanks to this process it is thus possible to combine the therapeutic activity of the active ingredient and the gel and even in some cases to benefit from a synergistic effect of the combination of the active ingredient and the gel, such as by homogenous integration of a corticosteroid in a polysaccharide-based matrix, the corticosteroid acting as an anti-inflammatory and protecting the gel from degradation, the gel allowing on the one hand controlled release active ingredient, and secondly an action of viscosupplementation (lubrication of the joint and shock absorption).

The major disadvantage of anti-inflammatories is to cause poor digestive tolerance, related to their haemorrhagic action on the gastric mucosa, which is often proportional to their activity.

Thus, the incorporation of the anti-inflammatory directly into the gel allows controlled diffusion, depending on whether the matrix is strongly or weakly functionalized, of this active ingredient directly in the area to be treated, while avoiding the aforementioned drawback. The gel of the present invention thus allows a targeted pharmacological action, optimized, while reducing the side effects.

For example, the addition of triamcinolone acetonide in a matrix according to the present invention allows in a single application to release during the residence time of the matrix, disposed within the target tissue, and without risk of irritation, anti-inflammatory for example to fight against rheumatological diseases such as arthritis

Thus, unexpectedly, biocompatible alcohols have been found to be good vectors for many amphiphilic as well as hydrophobic active principles that do not distribute directly homogeneously in a conventional type matrix.

It is obvious to those skilled in the art that the present invention is not limited to the examples cited (Trolox® and triamcinolone acetonide), and that other non-hydrophilic or amphiphilic molecules may be evenly distributed in a biocompatible alcohol or a mixture of biocompatible alcohols to obtain a homogeneous matrix.

As mentioned above, the biocompatible alcohol according to the present invention makes it possible to integrate the active ingredient (s) within the matrix. It plays a dual role here, that of vector of one or more active ingredients in a gel and that of pharmacologically active molecule.

Those skilled in the art will also determine the effective amount and not excessive amount of biocompatible alcohol necessary to dissolve the active ingredient (s). As illustrated by the examples below, a quantity of biocompatible alcohol of the order of 25/1 to 1/1

(m / m) relative to the amount of active ingredient is usually sufficient.

Biocompatible alcohols having in addition a pharmacological activity are preferred. These alcohols can be glycerol or propylene glycol or polyethylene glycol and its derivatives, alone or as a mixture. These have various interesting properties useful in the context of biocompatible gels.

- First, some of these biocompatible alcohols have antiseptic properties, which reduces the risk of infections. This risk is not negligible during a rejuvenation treatment of the cutaneous tissue, for example, given the large number of injections made in the face, décolleté, neck or hands. In addition, a biocompatible alcohol such as glycerol participates in the restructuring of the skin (moisturizers) and in the maturation of the cells of the target tissue.

In addition, certain biocompatible alcohols, such as glycerol, have an antioxidant property making it possible to protect the gel against free radicals and thus to delay the degradation of the gel.

Finally, because of their biocompatibility, these biocompatible alcohols do not need to be removed from the controlled-release gel, unlike other vectors that do not exhibit this biotolerance. In this case, the property of the biocompatible alcohol vector of lipophilic or amphiphilic active principles in a hydrophilic matrix is conjugated with the properties inherent to this alcohol.

It is however clear that the invention is not limited to glycerol and that other alcohols can be used such as for example propylene glycol or polyethylene glycol and its derivatives.

Another object of the invention is to allow controlled release of the active ingredient from the matrix according to the invention. This release is a function of various parameters intrinsic to said matrix. In fact, according to the degree of crosslinking of the matrix but also of the molecular weights and the concentration of the biopolymers forming this matrix, the matrix will have a residence time within the host organism which will vary.

It is known to those skilled in the art that in order to increase the remanence of the matrix, the tendency is to use high molecular weight polymers and / or to increase the concentration of polymers and / or increase the degree of crosslinking. However, a variation in the remanence of the matrix within the host organism may be a parameter for modifying the kinetics of release of the active principle. On the contrary, if the matrix is weakly functionalized, ie not protected by crosslinking or by grafting, the latter will be subjected more to the chemical and biochemical attacks induced by the host organism.

(enzymatic recognition). Therefore, the kinetics of release of the active ingredient in this host organism may be faster.

The release of the active ingredient may also depend on its particle size and its dissolution rate.

Thus, the degree of crosslinking of the matrices, the concentrations and molecular weights of the polymers constituting the gel can participate in the control of the diffusion of the active ingredient through the host organism.

Thus, the matrix according to the present invention comprises one or more polymers chosen for example from hyaluronic acid, chondroitin sulfate, keratan, keratan sulfate, heparin, heparan sulfate, cellulose and its derivatives, chitosan , xanthans and alginates, proteins, or nucleic acids.

The matrix may also comprise one or more biocompatible polymers of natural origin chosen, for example, from a polymer that is not naturally present in humans, such as a cellulose derivative, a xanthan or an alginate, said polymer not naturally present in humans. human is crosslinked with at least one polymer naturally present in humans selected from hyaluronic acid, chondroitin sulfate, keratan, keratan sulfate, heparin, heparan sulfate, proteins, or nucleic acids.

However, the invention is not limited to the aforementioned polymers. Polymers of different types and sizes can be used.

The matrix can be crosslinked. This technique is well known to those skilled in the art. For example, the matrix may be functionalized using a crosslinking agent which may be a bi or poly-functional molecule chosen, for example, from epoxides, epihalohydrins, or divinylsulfone.

In addition, the matrix according to the present invention may have highly crosslinked areas and less or not crosslinked areas, in order to control the kinetics of release of the active ingredient (s) of implantable or injectable gels.

Moreover, as shown in the examples below, the crosslinking of the matrix according to the invention does not disturb the dispersion. premix active ingredient / biocompatible alcohol within the matrix to form a homogeneous gel.

The present invention now provides the possibility of making homogeneous a matrix containing active principles, active ingredients that are not directly soluble in a conventional type of matrix.

The introduction of an amphiphilic or lipophilic pharmacologically active agent into a biopolymer gel has various advantages. In many diseases, the therapeutic efficacy depends on the residence time of the pharmacologically active agent in the host organism to be treated. Thus, the fact of being able to now introduce these agents into a conventional matrix by means of a specific vector, in this case a biocompatible alcohol, makes it possible to obtain a targeted, optimized and prolonged effect of this active ingredient within of the body while limiting possible side effects. It is also possible, depending on the time of action of the pharmacologically active agent introduced according to the disease to be treated, to adjust the remanence of the gel for a more or less prolonged effect, for example from a few hours to a few months. Indeed, controlled functionalization (that is to say a cross-linking and / or grafting) of the matrix allows gel remanence and release of the active ingredient (s) controlled, degradation / release profiles that can be adapted as a function of the target indication.

The progressive release of the pharmacologically active agent within said host organism no longer requires the need for repeated and binding administrations of the pharmacologically active agent for the patient.

It is also possible according to the desired needs to increase the doses of the pharmacologically active agent within the gel or on the contrary to limit this dose while having the same effect because this effect can be targeted. Furthermore, the gel according to the present invention has the advantage of acting systemically or locally on the host organism to be treated.

As an illustration, some gel compositions that can be prepared according to the invention are given below. The abbreviation "HA", used hereinafter, refers to hyaluronic acid. Gel based on HA / glycerol / triamcinolone acetonide

A biocompatible gel composed of hyaluronic acid at a rate of 1 to 50 mg / ml (mass / total volume of gel); preferably from 10 to 25 mg / ml, glycerol at a rate of 1-50 mg / ml (mass / total volume), preferably from 15 to 25 mg / ml, of triamcinolone acetonide at a rate of 0.01 to 100 mg / ml ( mass / total volume), preferably 1 to 50 mg / ml, is suitable for the present invention.

Gel based on HA / glycerol / betamethasone A biocompatible gel composed of hyaluronic acid at a rate of 1 to 50 mg / ml (mass / total volume of gel); preferably from 10 to 25 mg / ml, glycerol at a rate of 1 to 50 mg / ml (weight / volume), preferably from 15 to 25 mg / ml, of betamethasone at a rate of 0.01 to 100 mg / ml (weight / volume); preferentially: 1 to 50 mg / ml, is also suitable for the present invention.

Examples

Examples are provided to illustrate the invention, but are in no way limitative of said invention.

For the examples below, the functionalized biopolymer (s) (by crosslinking or grafting) and non-functionalized gels are prepared according to the techniques well known to those skilled in the art (see patents cited in US Pat. beginning of description).

Example 1

1 g of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox®) is brought into contact with 10 g of a gel based on hyaluronic acid (MM = 2.5 × 10 ⁶ Da) uncrosslinked at 20 mg / ml. The whole is mixed using a spatula (10 min). A gel is then obtained with lumps (aggregates) of Trolox® distributed heterogeneously in the gel.

However, if prior to introduction into 10 g of hyaluronic acid-based gel (MM = 2.5 × 10 ⁶ Da) not crosslinked at 20 mg / ml, Trolox® Ig is dissolved in 5 g of glycerol, we obtain then a homogeneous white gel. The same operation is carried out, but this time, the Trolox® / Glycerol mixture is integrated in a hyaluronic acid-based gel (MM = 2.5 × 10 ⁶ Da) at 20 mg / ml crosslinked at 6% (mass / mass) using the BDDE. The crosslinking of the hyaluronic acid does not disturb the dispersion of the Trolox® / glycerol mixture homogeneously in the matrix.

Example 2 (comparative)

A mixture of 10 g of hyaluronic acid-based gel (MM = 2.5 × 10 ⁶ Da) not crosslinked with 20 mg / ml and Trolox® Ig is prepared as in the first part of Example 1. 5 g of glycerol are added to this biphasic system containing lumps of Trolox®: after homogenization with a spatula (10 min), no improvement in the distribution of Trolox® in the gel is observed (the gel is not homogeneous) .

Example 3

0.2 g of triamcinolone acetonide, corticosteroid insoluble in aqueous medium, is mixed with a spatula (10 min) to 10 g of a gel based on hyaluronic acid (HA: MM = 2x10 ⁶ Da, 16 mg / ml) and carboxymethylcellulose (CMC: MM = 3x10 ⁵ Da, 4 mg / ml) crosslinked at 8% (w / w) using BDDE. In this case, it is impossible to obtain a homogeneous suspension of this anti-inflammatory agent within the biopolymer matrix. However, if 0.2 g of triamcinolone acetonide is dissolved beforehand in 2 g of glycerol, a matrix based on hyaluronic acid and crosslinked carboxymethylcellulose containing a homogeneous concentration of the anti-inflammatory agent is obtained.

Example 4

0.2 g of triamcinolone acetonide, an aqueous insoluble corticosteroid, is mixed with a spatula with 5 g of polyethylene glycol 200, and then the whole is mixed with a spatula (10 min) at 10 g of a gel based on hyaluronic acid (MM = 2 ^× 10 ⁶ Da) crosslinked at 7.5% (mass / mass) using BDDE. A homogeneous white gel is then obtained. Example 5

10 mg of triamcinolone acetonide, an insoluble cortisosteroid in aqueous medium, is dissolved in 200 mg of glycerol. This mixture is then added to 10 g of a gel based on hyaluronic acid (MM = 2.5 x 10 ⁶ Da) uncrosslinked to 18 mg / ml. After homogenization with a spatula

(10 min), the gel is in the form of a perfectly homogeneous suspension of the active ingredient in the biopolymer matrix. The gel thus obtained (= gel A) has a neutral pH, is isotonic and can be easily injected through a needle of diameter adapted to the indication and properties of the biopolymer matrix.

If the active ingredient is added directly to the gel, there is the presence of aggregates of active ingredient in the gel (= gel B).

Example 6: (study of homogeneity)

Description of the test:

The gels A and B prepared according to the description given in Example 5 are placed in 1 ml glass syringes (10 syringes / gel).

An assay (by HPLC) of the triamcinolone acetonide in a gel based on hyaluronic acid is carried out on the 10 syringes of the gel A and the 10 syringes of the gel B

- A coefficient of variation (CV = standard deviation / mean) is calculated on the 10 measurements obtained for each gel

Results:

- CV coefficient of variation for gel A = 2.3%

- Coefficient of variation CV for gel B = 48%

Unlike gel B, the standard deviation measured for gel A is very low.

Therefore, this test demonstrates that unlike the gel B (direct incorporation of the active ingredient into the gel), the triamcinolone acetonide is in homogeneous suspension in the gel A (gel prepared according to the present invention).

Example 7

200 mg of triamcinolone acetonide is dissolved in 200 mg of glycerol. This mixture is then added to 10 g of an acid-based gel hyaluronic acid (MM = 2x10 ⁶ Da) at 24 mg / ml, crosslinked at 8% (weight / mass) using BDDE. After homogenization with a spatula (10 min), the gel is in the form of a perfectly homogeneous suspension of the active ingredient in the crosslinked biopolymer matrix. The gel thus obtained has a neutral pH, is isotonic and can be easily injected through a needle of diameter adapted to the indication and properties of the biopolymer matrix.

If the active ingredient is added directly to the gel, there is the presence of aggregates of active ingredient in the gel (non-homogeneous active ingredient in the gel).

Example 8

10 mg betamethasone diproprionate, an insoluble cortisosteroid in aqueous medium, is dissolved in 200 mg of propylene glycol. This mixture is then added to 10 g of a gel based on hyaluronic acid (MM = 2.5 × 10 ⁶ Da) not cross-linked to 18 mg / ml. After homogenization with a spatula (10 min), the gel is in the form of a perfectly homogeneous suspension of the active ingredient in the biopolymer matrix. The gel thus obtained has a neutral pH, is isotonic and can be easily injected through a needle of diameter adapted to the indication and properties of the biopolymer matrix.

If the active ingredient is added directly to a gel, there is the presence of aggregates of active ingredient in the gel (non-homogeneous active ingredient in the gel).

Example 9

Betamethasone 60 mg is dissolved in 200 mg of propylene glycol. This mixture is then added to 10 g of a gel based on hyaluronic acid (HA: MM = 2 × 10 ⁶ Da, 17 mg / ml) and heparin (MM = 12000 Da, 3 mg / ml) crosslinked with 8 % (mass / mass) using BDDE. After homogenization with a spatula (10 min), the gel is in the form of a perfectly homogeneous suspension of the active ingredient in the biopolymer matrix. The gel thus obtained has a neutral pH, is isotonic and can be easily injected through a needle of diameter adapted to the indication and properties of the matrix biopolymers. If the active ingredient is added directly to the gel, there is the presence of aggregates of active ingredient in the gel (non-homogeneous active ingredient in the gel).

Example 10

10 mg of triamcinolone acetonide is dissolved in 90 mg of glycerol. This mixture is then added to 9.9 g of an HA gel (MM = 2.5 × 10 ⁶ Da) uncrosslinked at 13.8 mg / g.

After homogenization with a spatula (10 min), the gel is in the form of a perfectly homogeneous suspension of the active ingredient in the biopolymer matrix. The gel thus obtained has a neutral pH, and isotonic and can be easily injected through a needle of diameter adapted to the indication and properties of the biopolymer matrix.

Example 11: (Animal test)

Description of the test:

- Creation of an inflammation in the rat paw induced by the injection of a 1% carrageenan solution

Subcutaneous injection of 4 anti-inflammatory formulations including a formulation prepared according to the present invention (6 rats per formulation / volume injected for each formulation in the rat's paw = 0.1 ml); measurement of the percentage of inhibition of the inflammation relative to each formulation by plethysmography, that is to say by measuring the volume of the footprint over time (24 hours)

Formulations tested: - KENACORT® Delay diluted 1: 40: triamcinolone acetonide suspension (TA) diluted with water for injection

- Hyaluronic acid (HA) solution at 13.8 mg / ml (MM = 2.5 × 10 ⁶ Da)

Glycerol solution / TA (TA = 1 mg / ml) HA / glycerol / TA solution (TA = 1 mg / ml): formulation prepared according to the present invention (formulation of Example 10) Results: (see figure 1)

The HA / glycerol / TA formulation, prepared according to the present invention, has a high anti-inflammatory activity (greater than 50% inhibition) throughout the test, which is not the case with the other formulations.

Therefore, the combination according to the present invention induces an anti-inflammatory action of longer duration compared to

KENACORT® Delay diluted and TA / glycerol solution while the TA concentration is the same for these 3 formulations. It is also important to note that the standard deviations obtained in the case of the HA / glycerol / TA formulation are lower than for

KENACORT® diluted retard. This is a proof that the better homogeneity of the TA in the HA / glycerol / TA formulation makes it possible to obtain more reproducible results from one animal to another, compared to the diluted KENACORT® Delay formulation.

Claims

1. Process for the preparation of a biocompatible gel with controlled release of one or more lipophilic and / or amphiphilic active principles, with little or hardly water-soluble composition, comprising a matrix based on one or more functionalized biopolymers or non-functionalized, characterized in that:

in a first step, the lipophilic and / or amphiphilic active principle (s) are distributed homogeneously, by at least partial dissolution and suspended, in a biocompatible alcohol or a mixture of biocompatible alcohols

in a second step, the homogeneous mixture obtained in the first step is mixed with a biocompatible gel comprising a matrix of one or more functionalized or non-functionalized biopolymers;

2. Method according to claim 1, wherein during the first step the amphiphilic and / or lipophilic active ingredient (s) are distributed homogeneously, by total dissolution in a biocompatible alcohol or a mixture of biocompatible alcohols.

3. Method according to one of the preceding claims, wherein the biocompatible alcohol is pharmacologically active.

4. Method according to one of the preceding claims, wherein the biocompatible alcohol is glycerol and / or propylene glycol and / or polyethylene glycol or a derivative thereof.

5. Process according to claim 1, in which the lipophilic and / or amphiphilic active principle (s) used are chosen from hormones, angiogenic factors, growth factors, genes, anesthetics, anti-mitotics, anti-inflammatory steroids. , anti-radicals, vitamins, antihistamines or any other pharmacologically active dispersed agents.

6. Process according to claim 1, in which the lipophilic and / or amphiphilic active principle (s) used are chosen from anti-inflammatories of the corticosteroid family, such as (9-alpha-fluoro-11 beta, 21-dihydroxy- 16 alpha, 17 alpha-isopropylidenedioxypregna-1,4-diene-3,20-dione) and / or anti-radicals, such as 6-hydroxy-2,5,7,8-tetramethylchroman-2-acid; carboxylic acid, vitamin E and their pharmaceutically acceptable salts or derivatives.

7. The method of claim 1, wherein the biopolymer or biopolymers are selected from: hyaluronic acid, chondroitin sulfate, keratan, keratan sulfate, heparin, heparan sulfate, cellulose and its derivatives, the chitosan, xanthans and alginates, proteins, or nucleic acids.

8. The method of claim I ₅ wherein the functionalized gel is obtained from cross-linked biopolymer and / or grafted.

9. Biocompatible gel with controlled release of one or more lipophilic or amphiphilic active principles, obtained by the preparation method according to one of claims 1 to 8.

10. Release gel according to claim 9, characterized in that the biocompatible alcohol is pharmacologically active.

11. Controlled release gel according to claim 9 or

10, characterized in that the biocompatible alcohol is glycerol and / or propylene glycol and / or polyethylene glycol or a derivative thereof.

12. controlled release gel according to one of claims 9 to 11, characterized in that the active ingredient or lipophilic or amphiphilic used are selected from the hormones, angiogenic factors, growth factors, genes, anesthetics, anti-mitotics, steroidal anti-inflammatories, anti-radicals, vitamins, antihistamines, and pharmaceutically acceptable salts and derivatives thereof.

13. controlled release gel according to one of claims 9 to 12, characterized in that the lipophilic or amphiphilic active principle (s) used are chosen from antiinflammatories of the family of corticosteroids, such as (9-alpha-fluoro-11). beta, 21-dihydroxy-16 alpha, 17 alpha-isopropylidenedioxyprene-1, 4-diene-3,20-dione) formulas and / or anti-radicals, such as Y-6-hydroxy-2,5-acid, 7,8-tetramethylchroman-2-carboxylic acid, or vitamin E ₅ and their pharmaceutically acceptable salts and derivatives.

14. controlled release gel according to one of claims 9 to 13, characterized in that the gel has levels of crosslinking with highly crosslinked areas and less or not crosslinked areas, these different levels of crosslinking to obtain kinetics of controlled release of active principle (s).

15. controlled release gel according to one of claims 9 h 14, characterized in that the gel is injectable or implantable.

16. Controlled release gel according to any one of claims 9 to 14, characterized in that it comprises:

-. from 0.01 to 100 mg / ml (mass / total volume) of triamcinolone acetonide and / or betamethasone,

-. from 1 to 50 mg / ml (weight / total volume) of glycerol. -. hyaluronic acid with a molecular mass of 0.1 to 100 x 10 ⁶ Da.

-. from 1 to 50 mg / ml (mass / total volume) of hyaluronic acid

17. Controlled release gel according to claim 16, characterized in that it comprises:

-. from 1 to 50 mg / ml (mass / total volume) of triamcinolone acetonide and / or betamethasone,

-. from 15 to 25 mg / ml (mass / total volume) of glycerol,

-. hyaluronic acid with a molecular mass of 2 to 3 X 10 ⁶ Da.

-. from 10 to 25 mg / ml (mass / total volume) of hyaluronic acid

18. Controlled release gel according to claim 16, in which the hyaluronic acid is crosslinked using a biepoxide used in an amount of up to 15% (mass / mass). .

19. Controlled release gel according to one of claims 9 to 18, applied to separate, replace, fill, or supplement biological tissues.

20. Use of the controlled release gel according to one of claims 13 to 15 and 19, wherein the 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid is applied in the field of dermatology , ophthalmology or rheumatology, especially for its anti-radical activities.

21. Use of the controlled release gel according to one of claims 13 to 19, wherein triamcinolone acetonide is applied in the field of rheumatology, ophthalmology or in the treatment of allergic rhinitis.

22. Method of treatment, characterized in that a controlled release gel according to one of claims 9 to 21 is injected into a biological tissue so as to release a therapeutic substance and / or separating, replacing, filling, or supplementing said biological tissue.