WO2016198469A1

WO2016198469A1 - Penetration of alpha-hydroxy acids from water-free emulsions

Info

Publication number: WO2016198469A1
Application number: PCT/EP2016/063065
Authority: WO
Inventors: Åke LINDAHL; Niklas PALMKVIST; Lars Pettersson; Anders SJÖDIN
Original assignee: Hpf Ip Holding S.A.
Priority date: 2015-06-09
Filing date: 2016-06-08
Publication date: 2016-12-15

Abstract

The present invention generally relates to topical formulations of water-free emulsions for penetration of alpha-hydroxy acids, in particular lactic acid.

Description

PENETRATION OF ALPHA-HYDROXY ACIDS

FROM WATER-FREE EMULSIONS

FIELD OF THE INVENTION The present invention generally relates to topical formulations of water-free emulsions for penetration of alpha-hydroxyl acids, in particular lactic acid.

BACKGROUND OF THE INVENTION

In the attempt to reduce itch in skin, several attempts have been made. Various chemical agents have been tested and some work well but with the drawback of inducing various side effects. Several emulsion compositions have been tested for the ability to create an occluded environment, which prevents evaporation of water and thus decrease itch of various origin.

Inflammatory reactions often cause an increase of pH in the skin, or an increase of pH in the skin causes inflammation in the skin. Chronic pruritus affects millions of people worldwide, although solid epidemiological data is very limited. For example, one study reported that 8-10% of the population of Oslo suffer from chronic pruritus from several different causes (F. Dalgard et al, J. Investig. Dermatol. Symp. Proa, 2004, 9(2): 120-5).

Patients with certain diseases and conditions report high incidences of chronic itch, including those with psoriasis (78-84%), Hodgkin's disease (25-35%), dialysis patients (22%), and polycythaemica vera (48%) (M. Metz and S. Stander, CME Dermatol, 2008; 3(3): 124-143).

Chronic pruritus is also a prevalent symptom in cutaneous T-cell lymphoma (68-93%), a disease that includes mycosis fungoides and Sezary syndrome (N. Meyer et al, Acta Derm.

Venereol, 2010, 90:12-17). Pruritus is the most common dermatological complaint in elderly patients (S. Beauregard and B. A. Gilchrest, Arch. Dermatol, 1987, 123:1638-43). Itch is also often the side effect of certain drugs, such as EGF receptor antagonists.

Antihistamines can sometimes effectively treat itch due to acute urticaria, but many chronic pruritic diseases respond poorly to conventional HI receptor antagonists (Tey H. L. and G. Yosipovitch; Br. J. Dermatol, 2011, 165(1):5-17). In addition to marginal efficacy, systemic antihistamines can also cause intolerable drowsiness. Other current therapies possess various limitations. For example, anticonvulsants such as gabapentin inhibit spinal mechanisms in the perception of itch, but their use is limited due to their slow onset of action (5-6 weeks) (Metz and Stander, 2008). Opiate receptor antagonists such as naloxone, nalmefene, and naltrexone decreased pruritus symptoms in patients with liver and kidney disease, although significant central nervous and gastrointestinal side effects occurred (Metz and Stander, 2008; N. V. Bergasa et al, Hepatology, 2006, 44(5): 1317-23).

Substance P, the endogenous ligand for the neurokinin- 1 (NK-1) receptor, is a significant mediator of pruritus (T. Andoh et al, J. Pharmacol. Exp. Ther., 1998, 286:1140-5).

Intradermal injection of substance P elicits an itch sensation in human subjects, and an associated itch response in mice. The substance P-induced itch-associated response in mice is not inhibited by antihistamines (B. Amatya et al., Skin Pharmacol. Physiol, 2010; 23:133- 138; C. Weidner et al, J. Invest. Dermatol, 2000, 115:1015-1020). In an experiment designed to study the role of substance P in pruritus, Ohmura et al. reported that tachykinin NK-1 receptor antagonist, BIIF 1149 CL, inhibited scratching behaviour in a picrylchloride- induced dermatitis model inNC/Nga mice (Eur. J. Pharmacol, 2004, 491:191-194; U.S. Patent Application No. 2003/100565).

Aprepitant, an NK-1 receptor antagonist, is approved by the FDA for use in the prevention of chemically induced nausea and vomiting (emesis) after chemotherapy. Duval and Dubertret first reported that oral aprepitant (80 mg daily) had utility in treating pruritus in three patients with Sezary syndrome (N. Engl. J. Med., 2009, 361(14): 1415-6). Torres et al. disclosed similar results (J. Am. Acad. Dermatol, 2012; 66(l):el4-5). Stander et al.

conducted a small, open-label study, which demonstrated that aprepitant significantly decreased chronic pruritus caused by conditions such as atopic diathesis and prurigo nodularis. In this study, twenty previously untreatable patients were given a daily dose of 80 mg for 3 to 13 days. Eighty percent of the patients experienced a considerable reduction in itch intensity (S. Stander, et al, PLoS One, 2010, 5:6, el0968).

Atopic dermatitis (AD) is an inflammatory skin condition with severe pruritus as a central feature. Many factors are likely to contribute to the severe pruritus in AD, thereamong the on-going inflammatory process, which results in the release of various pruritogens, including histamine, bradykinin and serotonin (5-HT). Another central feature and a key contributor to pruritus in AD is the skin dryness. This is also suggested from animal models, in which skin dryness sensitizes the skin for pruritic stimuli (Akiyama T, Carstens MI,

Carstens E. Enhanced scratching evoked by PAR-2 agonist and 5-HT but not histamine in a mouse model of chronic dry skin itch. Pain. 2010;151(2):378-83). Yet another feature of AD skin is its abnormally high pH, which, similar to the skin dryness, might be related to a deficient skin barrier function. In a recent study, the mean pH value of lesional AD skin was 6.13 ± 0.52 as compared to 5.24 ± 0.40 in the healthy control group (Knor T, Meholjic- Fetahovic A, Mehmedagic A. Stratum corneum hydration and skin surface pH in patients with atopic dermatitis. Acta Dermatovenerol Croat. 2011;19(4):242-7). The complex interplay between inflammation, skin dryness and abnormal pH in relation to pruritus in AD is currently not investigated thoroughly.

There is therefore a need for additional, safe treatments for acute and chronic pruritus.

SUMMARY OF THE INVENTION

One object of the invention is to reduce inflammation by maintaining an acidic environment in and on the skin. Alpha-hydro xy acids are used for this purpose. A topical formulation has been developed which generates a large release of the acid from the formulation.

An aspect of the invention is a water free emulsion including a polar phase that can dissolve alpha-hydroxy acids and a lipid phase that can generate protective occlusion of the compromised skin barrier and facilitate penetration of other medically active agents.

In a related aspect of the invention, the topical formulation dissolves alpha-hydroxy acids and in particular lactic acid. If lactic acid is not dissolved, the acid will not penetrate the skin. Occlusive substances, lipids, do not dissolve lactic acid and therefore an emulsion is preferred having a lipid continuous phase and a discontinuous phase in which the lactic acid is soluble.

In one aspect of the invention, the discontinuous phase does not contain water (water is not to be added to this phase). The reason is that the acid will be charged and charged molecules do not penetrate into the skin readily. If, however, the discontinuous phase contains polar compounds in which lactic acid is soluble, a high penetration of lactic acid may be generated.

In a further embodiment, the polar phase may include alcohols and/or esters exemplified but not limited to diols, triols and esters of alpha hydroxy acids. Triols are polar and can form stable emulsions with lipids such as paraffin oil provided proper emulsifiers are used. However, triols such as glycerol do not facilitate skin penetration of lactic acid and we have found that diols are useful in generating both release and skin penetration of alpha hydroxy acids, including lactic acid.

In a further aspect of the invention, the discontinuous phase of the formulation may contain a diol in order to facilitate the release of an alpha-hydroxy acid, exemplified by but not limited to lactic acid, from the formulation. As earlier stated, there is evidence for the effect of alpha-hydroxy acids on several skin conditions, but in order to be effective the alpha-hydro xy acid must be released from the formulation.

In a related aspect of the invention, the increased release of alpha-hydroxy acids facilitated by the topical formulation described may help maintain a low pH (< pH 6), and help maintain an acidic environment in and on the skin. In related embodiments, such increased release of alpha-hydroxy acids facilitated by the topical formulation described maintains an acidic environment in and on the skin for several hours.

In yet another aspect of the invention, the formulation should preferably contain about 20 to 90% of continuous phase, more preferably 40 to 75%, and most preferably 50 to 60%>, in order to facilitate physical stability and occlusion.

One further aspect of the invention is to include a medically-active compound intended for the treatment or relief of dermatological conditions. Such compounds can be dissolved in either the lipid phase or in the polar phase. Non-limiting examples of such compounds are nuclear receptor agonists, nuclear receptor antagonists, non-steroidal antiinflammatory drugs, kinase inhibitors, phosphatase inhibitors, ion channel blockers, immunomodulators, G-protein coupled receptor antagonists, G-protein coupled receptor agonists, monoamine transporter blockers, enzyme inhibitors, anti-fibrotics or anti-infective substances, exemplified by but not limited to Mometasone, Diclofenac, Doxepin, Pramoxine, Calcipotriol, Apremilast, Tacrolimus, Tofacitinib, Pirfenidone, Desloratadin,

Hydrocortisone, Piroxicam, Clindamycin, Urea and Clobetasol.

In yet another aspect of the invention, the emulsion is formed and stabilized by the use of emulsifiers. Preferably, the emulsifier should have a HLB (hydrophile lipophile balance) value of 4 to 12, more preferably 5 to 11, and most preferably 5 to 9. The emulsion can be formed by a single emulsifier or by the use of a combination of several emulsifiers when HLB is calculated by methods known to a person skilled in the art.

Another related aspect of the invention is a water- free emulsion characterized by a continuous phase, comprising, consisting essentially of or consisting of one or several lipids, and a discontinuous phase, comprising, consisting essentially of or consisting of polar esters and alcohols and alpha-hydroxy acid compounds creating a pH of less than 5.5 when exposed to water, both phases being emulsified by surfactants said product being useful for restoring skin humidity and decrease itch.

A related aspect of the invention is an emulsion where the lipids can be defined by soft white paraffin, mineral and vegetable oils, and waxes suitable for pharmaceutical use. Another aspect of the invention is an emulsion where the polar esters can be defined as diols, represented by propandiol, and triols represented by glycerol in a relation of 2: 1 to 1 :5.

Another aspect of the invention is a formulation including a medical agent suitable for the treatment of dermatological conditions.

Another aspect of the invention is a formulation including a medical agent suitable for the treatment of dermatological conditions involving inflammation. DETAILED DESCRIPTION

The foregoing and other aspects of the present invention will now be described in more detail with respect to the description and methodologies provided herein. It should be appreciated that the invention may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the embodiments of the invention and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Also, as used herein, "and/or" refers to and encompasses any and all possible combinations of one or more of the associated listed items. Furthermore, the term "about," as used herein when referring to a measurable value such as an amount of a compound, dose, time, temperature, and the like, is meant to encompass, in addition to the measurable value, variations of 20%, 10%, 5%, 1%, 0.5%, or even 0.1% of the specified amount. When a range is employed (e.g., a range from x to y) it is it meant that the measurable value is a range from about x to about y, or any range therein, such as about xi to about yi, etc. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The invention provides an essentially-anhydrous topical formulation. The topical formulation comprises an emulsion, wherein the emulsion comprises a continuous phase and a discontinuous phase. The continuous phase is preferably a lipid phase.

As used herein, the term "lipid phase" refers to a non-polar or hydrophobic phase.

This hydrophobic phase preferably comprises hydrophobic or amphiphilic molecules, such as fats, waxes, sterols, fat-soluble vitamins, monoglycerides, diglycerides, triglycerides and/or phospholipids of natural or non-natural origin.

The continuous phase may contain one or more non-polar solvents, lipids and/or emulsifiers. Suitable components are di- and triglycerides or mixtures thereof, short chain monoglycerides (C8 to CI 2), fatty acid esters exemplified, but not limited to, cetyl esters, isopropyl esters of fatty acids esters such as isopropylmyristate or isopropylpalmitate. In one embodiment of the invention, the continuous phase contains a surfactant or a mixture of surfactants in order to facilitate the formation of an emulsion. Suitable surfactants or mixtures of surfactants have a hydrophile/lipophile balance of less than 9 and more than 4. In one embodiment, the emulsifier may contain saturated fatty acid esters exemplified but not limited to stearic, palmitic, myristic and lauric acids.

In another embodiment of the invention, the continuous phase may contain one or more thickening agents suitable for use in lipids. Furthermore, the continuous phase may contain thickening agents in the form of waxes, exemplified, but not limited to,

microcrystalline wax, carnuba wax, cerosine wax and cetyl esters wax. Other suitable types of thickening agents for lipids include, for example, polymeric thickeners such as ethylene vinyl alcohol copolymers and ethylene acrylic acid copolymers. Other examples are lipophilic fused silica particles and polyethene or polyethylene particles.

Examples of suitable lipids for the continuous phase include soft white paraffin, paraffin oil, mineral and vegetable oils, and waxes suitable for pharmaceutical use.

Preferably, the lipids are selected from medium chain triglycerides (e.g. whose fatty acids have an aliphatic tail of 6-12 carbon atoms) and paraffin oil.

The discontinuous phase is preferably a polar phase, more preferably an anhydrous (or essentially anhydrous) polar phase.

The polar phase preferably comprises one more polar compounds. In particular, the polar phase preferably comprises one or more polar compounds (polar solvents) which are capable of acting as solvents for alpha- hydroxy acids (preferably for lactic acid). In some embodiments, the polar phase includes one or more alcohols and/or esters. Examples of suitable alcohols and esters include diols, trio Is and esters of alpha-hydroxy acids.

In some embodiments, the discontinuous phase of the formulation contains a diol in order to facilitate the release of an alpha-hydroxy acid, exemplified by but not limited to lactic acid, from the formulation. Examples of suitable diols include propanediol, hexanediol and dipropylene glycol.

Trio Is are polar and can form stable emulsions with lipids (e.g. paraffin oil) provided that proper emulsifiers are used. However, trio Is such as glycerol do not facilitate skin penetration of lactic acid and we have found that diols are preferred for generating both release and skin penetration of alpha hydroxy acids, including lactic acid.

Examples of polar esters include polar citric acid and lactic acid esters. Other suitable solvents include esters such as propylene carbonate and ethers such as dimethyl isosorbide (dimethyl ether of an anhydride of an isomer of sorbitol, also usable as a penetration enhancer). It has been found that, in some embodiments, solvents can be mixed to generate higher solubility than if a single solvent is used. Preferably, the polar solvents are selected from glycerol, propylene glycol, dipropylene glycol and triethyl citrate, or a mixture thereof.

Another embodiment of the invention is an emulsion where the polar esters can be defined as diols, represented by propandiol, and trio Is represented by glycerol in a relation of 2:1 to 1:5.

The discontinuous phase (and preferably the continuous phase also) is preferably water-free or essentially anhydrous, i.e. it does not contain water (i.e. water is not to be added to this phase or the continuous phase). The reason for this is that alpha-hydroxy acids will be charged in an aqueous environment, and charged molecules do not penetrate into the skin readily. If, however, the discontinuous phase contains polar compounds in which alpha- hydroxy acids (e.g. lactic acid) are soluble, then a high penetration of the alpha-hydroxy acids (e.g. lactic acid) may be generated.

By water-free or "anhydrous" is meant that no water is added to the formulation (unless water is a constituent of the components added to the formulation, e.g. in hydrated form(s) or as in the case of lactic acid containing about 10 % of water). That is, no direct addition of water to a formulation of the present invention. However, those skilled in the art will recognize that water may be physically and/or chemically absorbed by a formulation and/or by one or more ingredients in a formulation at any time during the preparation, storage, and/or use of a formulation of the present invention (i.e., indirect addition of water to the formulation). In some embodiments, the term "anhydrous" means that a formulation has a water content of less than 5% by weight of the formulation or any range therein. A

formulation of the present invention may have a water content of less than about 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.5%, by weight of the composition. Water content may be measured by methods known to those of skill in the art, such as, but not limited to, Karl Fischer titration. Most preferably, the entire topical formulation is water- free, anhydrous or essentially anhydrous.

The discontinuous phase comprises an alpha-hydroxy acid. The role of pH for the development of itch in dermatological indications such as atopic dermatitis, ichthyosis and diaper dermatitis has been described in a recent paper. Saba M. Ali and Gil Yosipovitch," Skin pH: From Basic Science to Basic Skin Care" Acta Derm Venereol 2013; 93.

In dermatological diseases, the deficient barrier function of the skin membranes, mainly the stratum corneum, increases the evaporation of water from the skin (transepidermal water loss, TEWL), which negatively influences the healing process. Therefore, occlusive preparations can be useful in the treatment of dermatological diseases involving

compromised skin barrier.

It should therefore be beneficial to treat a patient with an occlusive product that can restore an acidic pH in the skin. It has been found that alpha hydroxyl acids, in particular lactic acid, are excellent for adjustment of pH and have low toxicity, and are also good candidates for restoring and maintaining the pH in the skin.

A topical formulation has been generated that can occlude the treated area and at the same time generate an acidic environment. We have also generated a water free formulation and at the same time made the solubility of an acidifying compound high. We found that a novel type of formulation, a water-free emulsion, comprising, consisting essentially of or consisting of a discontinuous polar phase and a continuous lipid phase, p/o (polar solvent in oil), solves the problem.

Water-free or non-aqueous emulsions are known in prior art (e.g. Petersen R.V., Hamill R.D. "Studies on nonaqueous emulsions" J. Soc. Cosmetic Chemists 19, 627-640 1968). A non-aqueous emulsion useful for drug delivery is described in US 5,110,606.

Palatable liquid therapeutic microemulsion wherein a drug dissolved in propylene glycol is dispersed in fatty ester. Lecithin is the emulsifier. US 5,110,606 does not mention

formulation of lactic acid and an occlusive product that can restore an acidic pH in the skin.

In one embodiment of this invention, the topical formulation comprises dissolved alpha hydroxy acids and in particular lactic acid. If lactic acid is not dissolved, the acid will not penetrate the skin. Occlusive substances, lipids, do not dissolve lactic acid and therefore an emulsion is preferred having a lipid continuous phase and a discontinuous phase in which the lactic acid is soluble.

In some embodiments, the alpha-hydroxy acid has a structure of Formula II:

wherein Rl and R2 are independently selected from H, CH₃, CH₂(COOH)- and phenyl. Preferably, R2 is H.

Examples of particularly preferred acids include lactic acid, citric acid, malic acid, glycolic acid and mandelic acid. Most preferably, the alpha-hydroxy acid is lactic acid.

Preferably, the amount of alpha-hydroxy acid in the topical formulation helps to maintain a low pH (< pH 6), and/or help maintain an acidic environment in and on the skin. Preferably, the topical formulation maintains a pH of less than 5.5, more preferably less than 5.2, and most preferably less than 5.0 on the skin. (The pH on the skin should also be maintained above pH 4.0 in order to avoid irritation on the skin, and preferably above 4.5).

The concentration or amount of alpha-hydroxy acid in the formulation is preferably a concentration or amount which is capable of maintaining the desired pH on the skin.

Preferably, the amount of alpha-hydroxy acid in the formulation is 0.1% to 5.0% (w/w), more preferably 0.2%- 1.0% (w/w).

In the embodiments of the invention wherein the alpha-hydroxy acid is lactic acid, the amount of lactic acid in the formulation is preferably 0.4-0.8% (w/w), more preferably 0.5- 0.7%) (w/w), and most preferably about 0.59%> (w/w).

In related embodiments, such increased release of alpha hydroxy acids facilitated by the topical formulation maintains an acidic environment in and on the skin for several hours.

As earlier stated, there is evidence for the effect of alpha-hydroxy acids on several skin conditions, but in order to be effective the alpha-hydroxy acid must be released from the formulation. In Examples 1 and 2, results are presented from a release study demonstrating increased release in the presence of diols compared with triols. The formulation should preferably contain about 20 to 90% of continuous phase (w/w), more preferably 40 to 75%, and most preferably 50 to 60%> in order to facilitate physical stability and occlusion.

The emulsion is preferably formed and stabilized by the use of one or more emulsifiers and/or surfactants. Preferably, the emulsifier should have a HLB

(hydrophile/lipophile balance) value of 4 to 12, more preferably 5 to 11 and most preferably 5 to 9. (HLB may be measured as the balance based on the molecular weight of the hydrophile (water loving) part and the lipophile (oil loving) part.) Preferably, the emulsifiers have saturated fatty acid chains. The emulsion can be formed by a single emulsifyer or surfactant or by the use of a combination of several emulsifiers or surfactants. Examples of preferred emulsifiers and surfactants include polyglycerol stearate and PEG 30

dipolyhydroxystearate (e.g. Citrol™ DPHS-SO-(MV)). The topical formulation of the invention preferably has a semi-solid viscosity.

In some embodiments, the topical formulation does not comprise a medically active compound intended for the treatment or relief of dermato logical conditions.

In some embodiments, the topical formulation does not comprise nuclear receptor agonists, nuclear receptor antagonists, non-steroidal anti-inflammatory drugs, kinase inhibitors, phosphatase inhibitors, ion channel blockers, immunomodulators, G-protein coupled receptor antagonists, G-protein coupled receptor agonists, monoamine transporter blockers, enzyme inhibitors, anti-fibrotics or anti-infective substances.

In some embodiments, the topical formulation does not comprise Mometasone, Diclofenac, Doxepin, Pramoxine, Calcipotriol, Apremilast, Tacrolimus, Tofacitinib, Pirfenidone, Desloratadin, Hydrocortisone, Piroxicam, Clindamycin, Urea or Clobetasol.

In particular, in some embodiments, the topical formulation of the invention does not comprise an aminoguanidine of Formula I:

or stereoisomers, tautomers and pharmaceutically acceptable salts, esters or prodrugs thereof, wherein:

R -R⁵ are independently H, Ci_₅-alkyl, OH, Ci_₅-alkoxy, SMe, SEt, CF₃, OCF₃, F, CI, Br, I, CN, S(0)Me, S(0)₂Me, S(0)₂NMe₂, NMe₂, NHC(0)H, NHC(0)Me, or CONMe₂, optionally including two adjacent groups, R'-R², R²-R³, R³-R⁴, or R⁴-R⁵, representing OCH₂0, OCH₂CH₂0 or SCH₂CH₂S;

X is absent or CH₂, (CH₂)₂, (CH₂)₃, CH=CH, CH₂CH=CH or CH=CHCH₂;

Y is absent or CH₂, (CH₂)₂, (CH₂)₃, CH₂)₄ or (CH₂)₅;

A is H, Ph or a 5-6 membered hetero-aromatic ring containing 1-3 hetero-atoms independently N, O or S; and

B is H, Me, Et, Ph, benzyl or OH.

In other embodiments of the invention, the topical formulation does not comprise an aminoguanidine.

In other embodiments of the invention, the topical formulation does not comprise a pharmaceutically active medicinal product. As used herein, the term 'medicinal product' means any substance or combination of substances presented for treating or preventing disease in human beings or animals and any substance or combination of substances which may be administered to human beings or animals with a view to making a medical diagnosis or to restoring, correcting or modifying physiological functions in humans or in animals. In particular, the term "medicinal product" refers to substance or combination of substances for which marketing authorisation has been granted in Europe or the US.

In some embodiments, the topical formulation additionally comprises a medically- active compound intended for the treatment or relief of dermato logical conditions. Such compounds can be dissolved in either the lipid phase or in the polar phase. Non-limiting examples of such compounds are nuclear receptor agonists, nuclear receptor antagonists, nonsteroidal anti-inflammatory drugs, kinase inhibitors, phosphatase inhibitors, ion channel blockers, immunomodulators, G-protein coupled receptor antagonists, G-protein coupled receptor agonists, monoamine transporter blockers, enzyme inhibitors, anti-fibrotics or anti- infective substances, exemplified by but not limited to Mometasone, Diclofenac, Doxepin, Pramoxine, Calcipotriol, Apremilast, Tacrolimus, Tofacitinib, Pirfenidone, Desloratadin, Hydrocortisone, Piroxicam, Clindamycin, Urea and Clobetasol.

The concentration of the active component in the formulation (if present) should be selected in such way that the desired pharmacological effect is achieved without causing adverse effects. This concentration is individual for each active component depending on its ability to pass the stratum corneum and its binding properties at the site of action as would be understood by one of ordinary skill in the art. In some embodiments, the concentration of the active components ranges from about 0.01 to about 10%, in some embodiments about 0.1 to about 10 %, in some embodiments about 0.1 to about 5%, in some embodiments about 0.5 to about 5 % by weight of the topical formulation. These concentration levels relate to certain dosage levels of the active components corresponding to a one, two, three or four times daily topical application of the formulation.

Furthermore, additional compounds which are often used in skin products but which are not included to treat dermatological conditions (i.e. they merely improve the properties of the formulation) may also be included. Examples of such compounds include, but are not limited to, chemical stabilisers, penetration enhancers, compounds giving texture to the formulation, pH modifiers, physical or chemical sun-blocking agents, antimicrobial agents, antioxidants, etc.

The invention also provides a topical formulation as defined herein for use in therapy or for use as a medicament.

Another embodiment of the invention is a formulation as defined herein for the treatment of dermatological conditions.

Another embodiment of the invention is a formulation as defined herein including a medical agent suitable for the treatment of dermatological conditions.

Another embodiment of the invention is a formulation including a medical agent suitable for the treatment of dermatological conditions involving inflammation.

The dermatological conditions which may be treated by the invention include dermatitis, psoriasis, skin fibrosis, pruritus/itch and pain.

Other conditions involving inflammation caused by infections or insults of various origins (fungal, bacterial, viral, parasitic, insects, poisonous plants) could also benefit from treatment, exemplified but not limited to conjunctivitis of different causes, blisters (e.g. herpes simplex, impetigo, hogweed, nettles), mycosis (e.g. superficial, cutaneous and subcutaneous), folliculitis, furnucles, carbuncles, eczema, cellulitis, erysipelas, varicella, shingles, scabies, bites/stings (e.g. caused by insects such as mosquitoes and wasps, and arachnids such as ticks).

In particular, the dermatological condition may be one which is caused by a viral, bacterial or fungal infection (e.g. infective dermatitis).

In some preferred embodiments, the viral infection to be treated is chickenpox, shingles or cold sores. In some preferred embodiments, the bacterial infection to be treated is impetigo, erysipelas, folliculitis or cellulitis. In other preferred embodiments, the bacterial infection is one caused by Staphylococci, Streptococci and/or Pseudomonas aeruginosa.

In some preferred embodiments, the fungal infection to be treated is dermatophyte) sis or tinea nigra.

Any portion of a subject's skin may be treated. However, in some embodiments, the subject's head, neck, face, trunk, upper extremities and/or lower extremities is treated. In some embodiments, the skin may be detached from a subject or may be a sample of skin, a skin graft or artificial skin.

"Skin" is intended to include, but is not be limited to, the epidermal and/or dermal layers, and may also include the underlying subcutaneous tissue. Mucosa (e.g., mouth, nasal, vaginal, etc.) and/or a surface of a subject's eye may also be treated.

Subjects suitable to be treated with formulations of the present invention include, but are not limited to, avian and mammalian subjects. Mammals according to the present invention include, but are not limited to, canines, felines, bovines, caprines, equines, ovines, porcines, rodents (e.g. rats and mice), lagomorphs, primates, humans, and the like, and mammals in utero. Any mammalian subject in need of being treated or desiring treatment according to the present invention is suitable. Human subjects of any gender (for example, male, female or transgender) and at any stage of development (i.e., neonate, infant, juvenile, adolescent, adult, elderly) may be treated according to the present invention.

In some preferred embodiments, the topical formulation is for paediatric use, e. g. for use on subjects aged between 0 and 18 years.

The invention may also be carried out on animal subjects, particularly mammalian subjects such as mice, rats, dogs, cats, livestock and horses for veterinary purposes, and for drug screening and drug development purposes. Illustrative avians according to the present invention include chickens, ducks, turkeys, geese, quail, pheasant, ratites (e.g., ostrich) and domesticated birds (e.g., parrots and canaries), and birds in ovo.

Subjects may be afflicted with or at risk of developing a dermato logical condition, including a dermatological inflammatory condition.

The invention also relates to a process for producing an essentially-anhydrous topical formulation, the process comprising the step of combining:

(i) one or more alpha-hydroxy acids and one or more polar compounds, with

(ii) one or more non-polar solvents, lipids and/or emulsifiers,

in order to produce an emulsion comprising: (a) a lipid continuous phase; and

(b) an essentially-anhydrous polar discontinuous phase which comprises the one or more alpha-hydroxy acids dissolved in the one or more polar compounds,

wherein no water is added during the production of the topical formulation.

Preferably, the alpha-hydroxy acids, polar compounds, non-polar solvents, lipids and/or emulsifiers are as defined in herein.

Unless otherwise defined, all terms, including technical and scientific terms used in the description, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

All patents, patent applications and publications referred to herein are incorporated by reference in their entirety. In the event of conflicting terminology, the present specification is controlling. Further, the embodiments described in one aspect of the present invention are not limited to the aspect described. The embodiments may also be applied to a different aspect of the invention as long as the embodiments do not prevent these aspects of the invention from operating for its intended purpose.

The present invention will now be described with reference to the following

Examples. It should be appreciated that these Examples are for the purpose of illustrating aspects of the present invention, and do not limit the scope of the invention as defined by the claims.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 : Release of lactic acid in relation to the composition of the polar phase (x-axis (hours), y-axis (%)). A contains 20=% of propylene glycol, B 10% of propylene glycol and C 0%) of propylene glycol.

Figure 2: Efficacy of formulation for treatment of pruritus over initial 12 hours. Median results are shown.

Figure 3: Efficacy of formulation for treatment of pruritus over 15 days. Median results are shown.

Figure 4: Efficacy of formulation for treatment of erythema over 15 days. Median results are shown. EXAMPLES

In this series of experiments, the technical features of the compositions are demonstrated.

EXAMPLE 1: PREPARATION OF FORMULATIONS

A series of formulations having different content of polar compounds were manufactured and tested for release of lactic acid from the formulation. Table 1: Formulations

To make A:

Charge medium chain triglycerides, Paraffin oil and fused silica particles in a container.

Stir carefully the fused silica particles into paraffin oil and Bergabest. Stir until a

homogenous viscous gel.

Add emulsifier and wax to the container.

Mix A to 80°C until all ingredients are melted.

Cool phase A to 75°C.

To make B :

Charge Propylene glycol, when applicable, glycerol and lactic acid to the beaker.

Heat phase B to 75°C. Slowly add B to A while stirring intensively (75°).

Homogenise at temperature, 75°C, the mixture intensively until a homogeneous emulsion. Note time.

The cream is cooled to ambient temperature with moderate stirring.

EXAMPLE 2: RELEASE OF LACTIC ACID IN VITRO

We have studied the release of lactic acid from the formulation using a synthetic membrane. The reason for not using pig ear skin is that lactic acid is a naturally occurring substance and enzymes in the skin can be active long after slaughter of the animal. The experiment is performed in a Franz diffusion cell using Ultracel^® 100 KDa cellulose membrane as barrier. The receptor fluid is water and we have samples after 3 and 6 hours.

The results are shown in Figure 1.

EXAMPLE 3: SOLUBILITY OF MEDICALLY ACTIVE AGENTS IN THE LIPID AND POLAR PHASE

We have studied the solubility of active compounds in the two phases of the product. The compositions of the phases are listed in Tables 2 and 3.

Table 2. Composition of lipid phi

Compound Amount

Emulsify er 6.76

Medium chain triglyceride 23.63

Paraffin oil 69.60

Total 100

Table 3. Composition of the polar phase.

Compound Amount

Propylene glycol 39.21

Glycerol 59.49

Lactic acid 1.29

Total 100

The solubility was studied by dissolving an excess amount of active to the respective phases at ambient temperature, 25 C, in 500 μΐ of the respective phases, stir and store the sample for >24 hours. The samples were centrifuged and analysed by HPLC.

Table 4. Solubility in lipid phase

Compound (%)

Mometasone 0.003

Hydrocortisone 0.032

Diclofenac 1.83

Piroxicam 0.034

Doxepin 0.012

Pramoxine 0.008 Calcipotriol 0.004

Clobetasol 0.022

Apremilast 0.01

Tacrolimus 0.03

Fusidic acid 0.022

Clindamycine < 1

Urea <5

Desloratadin 0.41

Tofacitinib <0.01 able 5. Solubility in polar phase

IN VITRO STUDIES

In the following four examples in vitro studies using pig ear skin as membrane were used. The studies were performed in a 14 cell Bronaugh equipment. The bronaugh cells are two compartment flow cells separated by the membrane where the upper compartment contains the donor, product, and the lower the receptor fluid. The fluid was pumped at a rate of 1.5 to 2 ml per hour and was collected for assaying for the active.

The membrane used was porcine ear skin the skin samples were dermatomed to about 0.5-1 mm. All membranes were taken from one individual and randomised before start.

Porcine ear skin was retrieved from a local slaughterhouse.

About 50 mg of each formulation was charged in each cell using a plastic pasteur pipette and the exact weight added was recorded. The receptor fluid was sampled at 3, 6 and 24 hours After the termination of the in vitro experiment, each cell was washed, dismounted and prepared according the following procedure:

1. The cell was washed by adding 0.5 ml of receptor solution with a pipette into the cell.

The solution was drawn and dispensed several times to clean the surface. The procedure was repeated 6 times and the fractions were collected in a test tube (total volume 3 ml). 2. The cell was dismounted.

3. The cell flange around the membrane (the unexposed skin) was cut with a 1 and the material was collected in a test tube.

4. The stratum corneum was gently separated from dermis with a scalpel and cut into thin strips. The material was collected in separate Eppendorf tubes.

The receptor solution samples were analysed according to method suitable for analysing the particular active by HPLC. The analysis of the skin samples was performed by adding 1.5 ml of acetonitrile to the samples to extract the active from the cut membranes. 3.0 ml of acetonitrile was added to the skin wash samples to dissolve the active substance. The samples were sonicated for 30 minutes in an Ultra bath before short vortex mixing. The samples were then centrifuged at 14500 rpm and transferred to HPLC vials for analysis. The samples were analysed directly after the in vitro run.

EXAMPLE 4: FORMULATION AND PENETRATION OF CALCIPOTRIOL

To make A:

Charge medium chain triglycerides, Paraffin oil and fused silica particles in a

container.

Stir carefully the fused silica particles into paraffin oil and Bergabest. Stir until a homogenous viscous gel. Add emulsifier and wax to the container.

Mix A to 80°C until all ingredients are melted.

Cool phase A to 75°C.

To make B:

Add calcipotriol, dissolve and Heat phase B to 75°C

Slowly add B to A while stirring intensively (75°).

Homogenise at 75°C, intensively until a homogeneous emulsion is generated.

The cream is cooled to ambient temperature with moderate stirring.

Receptor solution

The water solubility of Calcipotriol is 13.5 μg/ml and the substance is lipid in character. Therefore we have selected phosphate buffered saline, pH 7.4+ 2% PEG-20 oleyl ether as receptor fluid.

Skin

The porcine ear skin to be used in the study was dermatomed to about 0.5-1 mm. All membranes were taken from one individual and randomised before start.

Porcine ear skin was retrieved from a local slaughterhouse.

EXAMPLE 5: Formulation and penetration of Desloratadin

Compositions

1

A

Emulsifyer, poly glycerol stearate 3.01

Medium chain triglycerides 10.53

Paraffin oil 31.01

Microcrystalline wax 2.00

Fused silica particles 3.45

B

Desloratadin

0.5

Propylene glycol

19.56

Glycerol 29.35

Lactic acid

0.59

Total % (w/w) 100.00 Manufacture was performed according to Example 4 by exchanging the actives.

Receptor solution

The water solubility of desloratadin is very low, 4 μg/ml and the receptor phase selected was phosphate buffered saline, pH 7.4+ 2% PEG-20 oleyl ether. Desloratidine was found in dermis, in vitro tests, at levels above 300 ng/ml while very little penetration through the skin was detected. Desloratidine decreases the magnitude of effect of inflammatory reactions in cell suspension experiments above 1 ng/ml (Mullol J¹, Roca-Ferrer J, Alobid I, Pujols L, Valero A, Xaubet A, Bernal-Sprekelsen M, Picado C "Effect of desloratadine on epithelial cell granulocyte-macrophage colony- stimulating factor secretion and eosinophil survival." Clin Exp Allergy. 2006 Jan;36(l):52-8.). Compound 1 was not included in the penetration experiment performed; however it should not affect the data significantly.

EXAMPLE 6: Manufacture and penetration study of Tacrolimus

Manufacture was performed according to Example 4 with the difference of the active used. The water solubility of Tacrolimus is less than 5 μg/ml. The receptor phase selected was therefore phosphate buffered saline, pH 7.4+ 2% PEG-20 oleyl ether. EXAMPLE 7: Manufacture and penetration study of Apremilast

Manufacture was performed according to Example 4 with the difference of the active used. The water solubility of Apremilast is less than 5 μg/ml. The receptor phase selected was therefore phosphate buffered saline, pH 7.4+ 2% PEG-20 oleyl ether. The amount of Apremilast found in dermis, in vitro and pig ear skin, was about 20 ng/ml tissue. No penetration through skin was detected. Apremilast is expected to be effective as a PDE4 inhibitor at ng/ml level. P.H. Schafer^a' ' ,and A. Parton. et.al. ^a, "Apremilast is a selective PDE4 inhibitor with regulatory effects on innate immunity" Cellular Signalling Volume 26, Issue 9, September 2014, Pages 2016-2029. Compound 1 was not included in the penetration experiment performed; however it should not affect the data significantly.

IN VITRO PENETRATION OF STEROIDS

The next two examples will demonstrate the positive effect of the formulation on skin penetration of steroids. Since the aqueous solubility of steroids is low the receptor phase must contain organic solvents. This an accepted technique and the membrane used is silicon sheets. The membrane used was silastic sheeting NRV 0.005. The integrity test of the membrane was done visually and by testing leakage of receptor solution in the Franz equipment when mounted in the cells.

The receptor phase consists of the components in table below. The experiment is performed in a Franz cell equipment where the receptor fluid is static. Sampling is performed at termination of the experiment, at 6 hours. Raw materials used in receptor fluids for steroid experiments

Amount

Ethanol 95.5 % 59.9%

Water 40%

Acetic acid 0.1 %

Example 8: Penetration of Hydrocortisone

Manufacture was performed according to Example 4 with the difference of the active used. The release of hydrocortisone was estimated to be 60 ng/cm²*h in a 6 hour penetration experiment, see previous section for details. The relative standard deviation was 4.3 %. Compound 1 was not included in the penetration experiment performed; however it should not affect the data significantly. Example 9: Penetration of mometasone furanoate

*as mometasone

Manufacture was performed according to Example 4 with the difference of the active used. The release, experimental details see above, determined as flux through the silicone membrane, was on average 120 ng/cm²*h and the relative standard deviation was 6.9 %. Compound 1 was not included in the penetration experiment performed; however it should not affect the data significantly.

Table 6. Set up of 6 cells of the Franz equipment for silicon sheeting penetration.

Membrane type Formulation Applied

formulation

(mg)

1 Silicon* Example 8 276,8

2 Silicon* Example 8 277,2

3 Silicon* Example 8 260,3

4 Silicon* Example 9 256,8

5 Silicon* Example 9 264,1

6 Silicon* Example 9 260,7

Silastic sheeting NRV 0. 005 matt lot.SM05057619 ANALYSIS

Mometasone and hydrocortisone were analyzed by HPLC/UV according to current European pharmacopoeia, 7.0.

Example 10: Clinical study using formulation without active

The effect of the topical formulation without any active ingredient for the treatment of atopic dermatitis was tested in a Phase I/IIa study. Eight adult patients took part. These patients each had 5-40% of their body surface areas covered with eczema. The formulation was administered twice daily for 14 days, and once on day 15.

Composition of topical formulation

The efficacy of the formulation in relief from pruritus and erythema over the 15 -day trial period is shown in Figures 2-4. Pruritus was assessed by the Visual Analogue Scale (VAS). This scale runs from 0 (no itch) to 100mm (most severe itch that the patient can imagine).

Figure 2 shows the fast onset of the formulation for the treatment of pruritus: relief from pruritus starts within 1 hour of application of the formulation to the skin. Figure 3 shows that relief from pruritus was sustained over the 15 day trial period.

Figure 4 shows the effect of the formulation on the treatment of erythema. Erythema was evaluated by the clinical staff. (Scale: 0 = no erythema, 1 = very slight, 2 = well-defined, 3 moderate to severe, 4 = severe erythema.)

Example 11: Antibacterial effect of the formulation

The antibacterial effect of the topical formulation was evaluated by assessing its effect on Staphylococcus aureus. The composition of the formulation is given below:

Composition of topical formulation

The results are given below:

Results of efficacy of antimicrobial preservation on each microorganism. Results are presented as logui differences between the different time points

Comparison time Bacteria logio reduction Staphylococcus aureus

Day 0-0 hours > 5.3

Day 0-2 hours 5.3

Day 0-4 hours > 5.3

Day 0-4 hours > 5.3 The results show that the antimicrobial efficacy of the formulation is good with a reduction of S. aureus. The instantaneous reduction (< 20 minutes) is more than log 5.3.

Claims

1. An essentially-anhydrous topical formulation comprising an emulsion, wherein the emulsion comprises:

(a) a lipid continuous phase; and

(b) a polar discontinuous phase which comprises one or more alpha-hydroxy acids dissolved in one or more polar compounds.

2. A topical formulation as claimed in claim 1, wherein the topical formulation does not comprise an aminoguanidine of Formula I:

or stereoisomers, tautomers or pharmaceutically acceptable salts, esters or prodrugs thereof, wherein:

X is absent or CH₂, (CH₂)₂, (CH₂)₃, CH=CH, CH₂CH=CH or CH=CHCH₂;

Y is absent or CH₂, (CH₂)₂, (CH₂)₃, CH₂)₄ or (CH₂)₅;

A is H, Ph or a 5-6 membered hetero-aromatic ring containing 1-3 hetero-atoms

independently N, O or S; and

B is H, Me, Et, Ph, benzyl or OH.

3. A topical formulation as claimed in claim 1, wherein the topical formulation does not comprise an aminoguanidine.

4. A topical formulation as claimed in any one of claims 1 to 3, wherein the alpha-hydroxy acids are of general Formula II:

OH

II

O

R2- -C

OH

Rl wherein Rl and R2 are independently selected from H, CH₃, CH₂(COOH)- and phenyl; preferably wherein R2 is H.

5. A topical formulation as claimed in any one of claims 1 to 4, which comprises an amount of alpha-hydroxy acid which, when the topical formulation is applied to human skin, is sufficient to maintain a pH of less than pH 6.0 on the skin, preferably less than pH 5.5, and more preferably less than pH 5.2.

6. A topical formulation as claimed in any one of claims 1 to 5, which comprises 0.1% to 5.0% (w/w), preferably 0.2%>-1.0%> (w/w), of alpha-hydroxy acids.

7. A topical formulation as claimed in any one of claims 1 to 6, wherein the alpha- hydroxy acid is lactic acid, citric acid, gly colic acid or mandelic acid, preferably lactic acid.

8. A topical formulation as claimed in any one of claims 1 to 7, wherein the polar compounds are selected from alcohols and esters.

9. A topical formulation as claimed in claim 8, wherein the alcohols and esters are selected from diols, trio Is and esters of alpha-hydroxy acids.

A topical formulation as claimed in any one of claims 1 to 9, wherein the continuous comprises one or more non-polar solvents, lipids and/or emulsifiers.

11. A topical formulation as claimed in any one of claims 1 to 10, wherein the topical formulation comprises about 20 to 90%> (w/w) of continuous phase, more preferably 40 to 75%), and most preferably 50 to 60%>.

12. A topical formulation as claimed in any one of claims 1 to 11, wherein the topical formulation does not comprise Mometasone, Diclofenac, Doxepin, Pramoxine, Calcipotriol, Apremilast, Tacrolimus, Tofacitinib, Pirfenidone, Desloratadin, Hydrocortisone, Piroxicam, Clindamycin, Urea or Clobetasol.

13. A topical formulation as claimed in any one of claims 1 to 11, wherein the topical formulation does not comprise nuclear receptor agonists, nuclear receptor antagonists, nonsteroidal anti-inflammatory drugs, kinase inhibitors, phosphatase inhibitors, ion channel blockers, immunomodulators, G-protein coupled receptor antagonists, G-protein coupled receptor agonists, monoamine transporter blockers, enzyme inhibitors, anti-fibrotics or anti- infective substances.

14. A topical formulation as claimed in any one of claims 1 to 11, wherein the topical formulation does not comprise a medically-active compound intended for the treatment or relief of dermatological conditions.

15. A topical formulation as claimed in any one of claims 1 to 11, wherein the topical formulation does not comprise a pharmaceutically- active medicinal product.

16. A topical formulation as claimed in any one of claims 1 to 11, wherein the topical formulation additionally comprises a pharmaceutically-active medicinal product.

17. A topical formulation as claimed in any one of claims 1 to 11, wherein the topical formulation additionally comprises a medically-active compound intended for the treatment or relief of one or more dermatological conditions.

18. A topical formulation as claimed in any one of claims 1 to 11, wherein the topical formulation additionally comprises one or more nuclear receptor agonists, nuclear receptor antagonists, non-steroidal anti-inflammatory drugs, kinase inhibitors, phosphatase inhibitors, ion channel blockers, immunomodulators, G-protein coupled receptor antagonists, G-protein coupled receptor agonists, monoamine transporter blockers, enzyme inhibitors, anti-fibrotics or anti-infective substances.

19. A topical formulation as claimed in any one of claims 1 to 11, wherein the topical formulation additionally comprises one or more of Mometasone, Diclofenac, Doxepin, Pramoxine, Calcipotriol, Apremilast, Tacrolimus, Tofacitinib, Pirfenidone, Desloratadin, Hydrocortisone, Piroxicam, Clindamycin, Urea or Clobetasol.

20. A topical formulation as claimed in any one of claims 1 to 19, wherein the topical formulation is for use in therapy or for use as a medicament.

21. A topical formulation as claimed in any one of claims 1 to 19, wherein the topical formulation is for use in treating a dermato logical condition.

22. A method of treating a dermato logical condition comprising applying the topical formulation as claimed in any one of claims 1 to 19 to the skin of a patient in need thereof

23. Use of a topical formulation as claimed in any one of claims 1 to 19 in the preparation of a medicament for treating a dermatological condition.

24. A topical formulation as claimed in claim 21, a method as claimed in claim 22 or a use as claim in claim 23, wherein the dermatological condition is an inflammatory dermatological condition.

25. A topical formulation as claimed in claim 21, a method as claimed in claim 22 or a use as claim in claim 23, wherein the dermatological condition is dermatitis, psoriasis, skin fibrosis, pruritus/itch or pain.

26. A topical formulation as claimed in claim 21, a method as claimed in claim 22 or a use as claim in claim 23, wherein the dermatological condition is caused by a viral, bacterial or fungal infection.

27. A process for producing an essentially-anhydrous topical formulation, the process comprising the step of combining:

(i) one or more alpha-hydroxy acids and one or more polar compounds, with

(ii) one or more non-polar solvents, lipids and/or emulsifiers,

in order to produce an emulsion comprising: (a) a lipid continuous phase; and

wherein no water is added during the production of the topical formulation.

28. A process as claimed in claim 27, wherein the alpha-hydroxy acids, polar compounds, non-polar solvents, lipids and/or emulsifiers are as defined in any one of claims 1 to 10.

29. A process as claimed in claim 27, wherein the topical formulation is as defined in any one of claims 1 to 19.