WO2004047789A1

WO2004047789A1 - Cosmetic composition, containing coumarin derivatives and lipophilic amino acid derivatives

Info

Publication number: WO2004047789A1
Application number: PCT/EP2003/012919
Authority: WO
Inventors: Carole Guiramand
Original assignee: L'oreal
Priority date: 2002-11-22
Filing date: 2003-11-18
Publication date: 2004-06-10
Also published as: AU2003288109A1

Abstract

The present invention relates to a cosmetic composition comprising, in a physiologically acceptable medium, at least one coumarin derivative and at least one lipophilic amino acid derivative. The coumarin derivative is preferably a bicyclic or tricyclic disubstituted coumarin, for example esculetin or its derivatives, or visnadine or its derivatives. The invention also relates to the cosmetic uses of a composition according to the invention, and also to the cosmetic treatment process that consists in applying a composition according to the invention to the skin. The invention also relates to a process for dissolving a coumarin derivative using a lipophilic amino acid derivative.

Description

COSMETIC COMPOSITION CONTAINING COUMARIN DERIVATIVES AND LIPOPHILIC AMINO ACID DERIVATIVES

The present invention relates to a composition, especially a cosmetic composition, comprising a coumarin derivative and a lipophilic amino acid derivative, and also to its uses in cosmetics and/or dermatology. The invention also relates to a process for dissolving a coumarin derivative with a lipophilic amino acid derivative.

It is known practice to use active agents in cosmetic and/or der atological compositions, for example in order to care for or treat the skin or to provide beneficial effects thereto. However, the use of some of these active agents poses a problem since they are in crystalline form and are sparingly soluble or not at all soluble in water. Thus, if they are introduced in unmodified form into cosmetic and/or dermatological compositions, they remain in the form of crystals, which makes the composition containing them ineffective for use in treating the skin. In general, and for some of them, it is possible to introduce them in the presence of a solvent, but the presence of this solvent is not always desirable_, especially during application to certain areas of the face, such as around the eyes.

This is the case in particular for compounds such as visnadine or its derivatives. These active principles are of cosmetic interest, especially on account of their action on capillary circulation. In order to ensure good dissolution, these compounds are generally 'formulated in the presence of lipophilic constituents. Among these- known solubilizers, mention may be made of capric/caprylic acid triglycerides and isopropyl myristate. Similarly, these compounds may be formulated in the presence of glycols. However, vis.nadine has a tendency to recrystallize readily, which limits the amount of compound used. In order to overcome this drawback, the increase in the amount of solubilizer, in particular of those mentioned above, results in a rapid degradation of the cosmetic qualities and the stability of the compositions.

There is thus a need to be able to introduce these compounds of low solubility, in sufficient amount, into cosmetic and/or dermatological compositions, especially into the lipophilic phase of such compositions, without any loss of cosmetic efficacy. It thus remains necessary to be able readily to dissolve coumarin derivatives in a physiologically acceptable medium that results in a minimum level of discomfort when applied to the skin or the scalp, and which is easy to use. In addition, it is necessary to be able to dissolve a sufficient amount of these compounds for cosmetic or dermatological use, without recrystallization of these compounds or loss of stability of the composition containing them. This is because this instability would result in a more or less substantial loss of efficacy of these compositions and/or a change in their appearance, which would run the risk of discouraging users from using them.

The Applicant has now found that lipophilic amino acid derivatives make it possible, unexpectedly, to increase the solubilization of these coumarin derivatives. One subject of the present invention is thus a composition comprising, in a physiologically acceptable medium, at least one coumarin derivative and at least one lipophilic amino acid derivative. In the present patent application, the expression "physiologically acceptable medium" means a medium that is compatible with the skin, including the scalp, mucous membranes, the eyes and/or the hair.

The main advantage of using the lipophilic amino acid derivatives according to the invention is that they make it possible to dissolve a sufficient amount of coumarin derivatives, for the purpose of a cosmetic or dermatological use, without recrystallization of the said coumarin derivatives or loss of stability of the composition containing them, and thus make it possible to obtain a cosmetically acceptable composition.

The coumarin derivatives used in the compositions according to the invention are advantageously chosen from unsubstituted coumarins, monosubstituted and disubstituted

^■ coumarins, and/or mixtures thereof, their optional enantiomers, diastereoisomers, or mixtures thereof, including racemic mixtures.

In one advantageous aspect of the invention, the coumarin derivatives will be ^"chosen from disubstituted coumarins. In particular, these disubstituted coumarins may be chosen from bicyclic coumarins and tricyclic coumarins.

In one particular aspect of the invention, the bicyclic coumarins used are represented by formula (I) :

in which R represents a hydrogen atom or a linear or branched, saturated or unsaturated alkyl group containing from 1 to 20 carbon atoms, which is optionally hydroxylated, and one carbon atom of which may be replaced with a hetero atom chosen from oxygen, nitrogen and sulphur atoms; and Ri and R₂ independently represent a hydrogen atom or a group chosen from R₃o, -0-R₃ι, -N-R₃ιR₃₂, -CO-R₃ι and -O~CO-R₃₀, in which: R₃₀ represents a group chosen from linear or branched, saturated or unsaturated alkyl groups containing from 1 to 20 carbon atoms, which is optionally hydroxylated, and one carbon atom of which may be replaced wi-th a hetero atom chosen from oxygen, nitrogen and sulphur atoms; cycloalkyl containing from 3 to 8 carbon atoms, optionally hydroxylated, and one carbon atom of which may be replaced with a hetero atom chosen from oxygen, nitrogen and sulphur atoms; optionally substituted aryl; 5- to 11-membered monocyclic or bicyclic heteroaryl containing at least one aromatic ring, and containing from 1 to 5 hetero atoms chosen from nitrogen, oxygen and sulphur, optionally substituted; an afylalkyl group in which the aryl and alkyl radicals have the same meaning as above; and heteroarylalkyl in which the heteroaryl and alkyl radicals have the same meaning as above; and a sugar residue; R₃ι and R₃₂ independently represent a hydrogen atom or a group R₃o, their optional enantiomers, diastereoisomers, or mixtures thereof, including racemic mixtures.

In another particular aspect of the invention, the tricyclic coumarins used are chosen from the compounds of formula (II) :

in which R and R₅ independently represent an alkyl group containing from 1 to 6 carbon atoms, and Rε and R₇ independently represent a hydrogen atom or a group chosen from R₆₀, -O-Rei, -N-R6-.R62. -CO-Rβi or -0-CO-R₆o- in which:

R₆o represents a group chosen from linear or branched, saturated or unsaturated alkyl groups containing from 1 to 20 carbon atoms, optionally hydroxylated, and one carbon atom of which may be replaced with a hetero atom chosen from oxygen, nitrogen and sulphur atoms; cycloalkyl containing from 3 to 8 carbon atoms, optionally hydroxylated, and one carbon atom of which may be replaced with a hetero atom chosen from oxygen, nitrogen and sulphur atoms; optionally substituted aryl; 5- to 11-membered monocyclic or bicyclic heteroaryl containing at least one aromatic ring, and containing from 1 to 5 hetero atoms chosen from nitrogen, oxygen and sulphur, optionally substituted; an arylalkyl group in which the aryl and alkyl radicals have the same meaning as above; and heteroarylalkyl in which the heteroaryl and alkyl radicals have the same meaning as above; and a sugar residue; R₆ι and Rβ₂ independently represent a hydrogen atom or a group Reo-- their optional enantiomers, diastereoisomers, or mixtures thereof, including racemic mixtures.

In the compounds of formula (I) or (II) above, among the linear or branched alkyl radicals containing from 1 to 30 carbon atoms that may advantageously be mentioned are methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert- butyl, 2-butyl, pentyl, isopentyl, hexyl, octyl, nonyl, 2- ethylhexyl, dodecyl, hexadecyl, behenyl, octadecyl and 2- butyloctyl radicals. These radicals preferably contain from 1 to 12 carbon atoms. Even more preferably, the alkyl radical contains from 1 to 6 carbon atoms. Lower alkyl radicals that may be mentioned include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2-butyl, pentyl, isopentyl and hexyl radicals. When it is unsaturated, the radical that is preferred, is one containing one or more ethylenic unsaturations, more particularly such as the allyl radical.

When the alkyl radical is cyclic, mention may be made especially of the cyclohexyl, cholesteryl or tert- butylcyclohexyl radical.

When it is hydroxylated, the radical ' preferably contains from 1 to 6 carbon atoms and from 1 to 5 hydroxyl groups . Among the monohydroxyalkyl radicals that are preferred is a radical preferably containing from 1 to 3 carbon atoms, especially hydroxymethyl, 2-hydroxyethyl, and 2- or 3- hydroxypropyl radicals.

Among the polyhydroxyalkyl radicals that are preferred is a radical containing from 3 to 6 carbon atoms and from 2 to 5 hydroxyl groups, such as 2, 3-dihydroxypropyl, 2,3,4- trihydroxybutyl, 2, 3, 4, 5-tetrahydroxypentyl and 2,3,4,5,6- pentahydroxyhexyl radicals.

Examples of aryl radicals that may be mentioned include phenyl, naphthyl and biphenyl radicals. Examples of heteroaryl radicals that may be mentioned include pyridyl, furyl, thienyl and imidazolyl radicals.

The term "optionally substituted" associated with the aryl and heteroaryl groups means that these groups are unsubstituted or substituted with one or more halogen, atoms or alkyl, hydroxyl, alkoxy^", cyano, amino (optionally substituted with one or two alkyl groups) , nitro, carboxyl, alkoxycarbonyl, aminocarbonyl (optionally substituted with one or two alkyl groups) and carbamoyl groups. The term "sugar residue" means a radical derived from a monosaccharide, disaccharide or trisaccharide, among which mention may be made of glucose, galactose, maltose, rhamnose and glucuronic acid. Reference will be made most particularly to glucose. The sugar residue may be attached to the coumarin. nucleus via any of the oxygen atoms it contains, and preferably via the oxygen atom in the anomeric position.

Advantageously, in the compounds of formula (I) , the group R represents a hydrogen atom or a lower alkyl group of 1 to 6 carbon atoms as defined above. Advantageously, in the compounds of formula (I), the groups Ri and R₂ independently represent a group -0-R₃χ in which R₃ι is advantageously chosen from a hydrogen atom, an alkyl group as defined above and a sugar residue.

A compound of formula (I) that is particularly suitable for the implementation of the present invention is esculoside, for which R_x represents a hydroxyl group and R₂ represents a group -0-R₃ι in which R₃ι is a glucose residue:

Another compound of formula (I) that is particularly suitable for the implementation of the present invention is methylesculetin, of formula:

These compounds may be obtained conventionally via chemical synthesis, or else may be extracted from common horse chestnut.

Advantageously, the compounds of formula (II) are chosen from visnadine and its derivatives, i.e. compounds for which the groups R₄ and R₅ each represent a methyl group. In the preferred compounds of formula (II) , the groups R₆ and R₇ independently represent a group -0-CO-R₆ι as defined above, R₅ι preferably being an alkyl group as defined above. A compound of formula (II) that is particularly suitable for implementing the present invention is visnadine, for which R₄ and R₅ each represent a methyl group, R₆ represents a group -O-CO-Rβi in which Rβi is a 2-butyl group, and R₇ represents a group -0-C0-R₆ι in which Rεi is a methyl group:

The lipophilic amino acid derivative is preferably an ester chosen from the amino acid esters of formula (III) : R'ι(CO)N(R'₂)CH(R'₃) (CH₂) _n (CO) OR' ₄ (III) in which: n is an integer equal to 0, 1 or 2,

R' i represents a linear or branched C₅ to C₂ι alkyl or alkenyl radical,

R' ₂ represents a hydrogen atom or a Ci to C₃ alkyl group,

R'₃ represents a radical chosen from the group formed by a hydrogen atom, a methyl group, an ethyl group and a linear or branched C₃ or C₄ alkyl radical, R' represents a linear or branched Ci to Cι₀ alkyl radical, a linear or branched C₂ to Cι₀ alkenyl radical or a sterol residue. These amino acid esters and the process for synthesizing them are described in patent applications EP 1 044 676 and EP 0 928 608 from the company Ajinomoto Co. In the amino acid esters of formula (III) , the group R'ι(CO)- is preferably an acyl group of an acid preferably chosen from the group formed by capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, linoleic acid, linolenic acid, oleic acid, isostearic acid and 2-ethylhexanoic acid, coconut oil fatty acids and palm kernel oil fatty acids. These fatty acids may also contain a hydroxyl group. Even more preferably, the fatty acid will be lauric acid.

The portion -N (R'₂) CH (R' ₃) (CH₂)_n(CO) - of the amino acid ester is preferably chosen from the following amino acids: glycine, alanine, valine, leucine, isoleucine, serine, threonine, proline, hydroxyproline, β-alanine, aminobutyric acid, aminocaproic acid, sarcosine and N-methyl-β-alanine. Even more preferably, the amino acid will be sarcosine. The portion of the amino acid esters corresponding to the group OR' may be obtained from alcohols chosen from the group formed by methanol, ethanol, propanol, isopropanol, butanol, tert-butanol, isobutanol, 3-methyl-l-butanbl, 2- methyl-1-butanol, fusel oil, pentanol, hexanol, cyclohexanol, octanol, 2-ethylhexanol, decanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, cetostearyl alcohol, stearyl alcohol, oleyl alcohol, behenyl alcohol, jojoba alcohol, 2-hexadecyl alcohol, 2-octyldodecanol and isostearyl alcohol.

These amino acid esters may be obtained in particular from natural sources of amino acids. In this case, the amino acids are derived from the hydrolysis of natural proteins from plants (oat, wheat, soybean, palm or coconut) and, in ,this ,case, necessarily lead to amino acid mixtures that must then be esterified and then N-acylated. The preparation of such amino acids is more particularly described in patent application FR 2 796 550, which is incorporated herein by reference.

The amino acid ester that is more particularly preferred for use in the present invention is isopropyl N-lauroylsarcosinate of 'formula:

CH₃- (CH₂) _IOCO-N (CH₃) -CH₂-COO-CH₂- (CH₃) ₂.

The concentration of coumarin derivatives in the composition according to the present invention is between 0.001% and 30%, preferably between 0.001% and 20% and even more preferably between 0.1% and 5% by weight relative to the total weight of the composition. The amount of amino acid esters will depend on the amount of coumarin derivatives to be dissolved, and may be between 0.01% and 90% by weight and preferably between 0.1% and 30% by weight relative to the total weight of the composition.

The composition according to the invention may be used as a cosmetic composition, in particular to improve the capillary circulation, as a slimming composition, to combat cellulite, or as a composition intended to be applied around the eyes, in particular to combat the formation of bags and/or shadows under the eyes .

The composition according to the present invention may also be used for the manufacture of a dermatologic'al preparation.

Further subjects of the invention are the cosmetic use of the composition as defined above as a slimming composition, to combat cellulite, and to combat the formation of bags and/or shadows under the eyes, and a cosmetic treatment process for slimming, for combating cellulite and for combating the formation of bags and/or shadows under the eyes, which comprises the application of a composition according to the invention to the skin.

The compositions used ^' according to the invention are intended for topical application to the skin and/or its integuments and thus contain a physiologically acceptable medium, i.e. a medium that is compatible with cutaneous tissues such as the skin, the scalp, the eyelashes, the eyebrows, the hair, the nails and/or mucous membranes. This physiologically acceptable medium may consist more particularly of water and optionally of a physiologically acceptable organic solvent chosen, for example, from lower alcohols containing from 1 to 8 carbon atoms and in particular from 1 to 6 carbon atoms, for instance ethanol, isopropanol, propanol or butanol; polyethylene glycols containing from 6 to 80 ethylene oxide units; polyols, for instance propylene glycol, isoprene glycol, butylene glycol, glycerol, sorbitol, dipropylene glycol, pentylene glycol and hexylene glycol .

The compositions according to the invention may be J-n any presentation form conventionally used for topical application and especially in the form of aqueous or aqueous-alcoholic solutions, oil-in-water (O/W) emulsions or water-in-oil (W/O) emulsions . or multiple emulsions

(triple emulsion: W/O/W or 0/W/O) , aqueous gels, or

, dispersions of an oily phase in an aqueous phase using spherules, these spherules possibly being polymer nanoparticles such as nanospheres and nanocapsules, or lipid vesicles of ionic and/or nonionic type (liposomes, niosomes or oleosomes) . These compositions are prepared according to the usual methods.

In addition, the compositions used according to the invention may be more or less fluid and may have the appearance of a white or coloured cream, an ointment, a milk, a lotion, a serum, a paste, a mousse or a two-phase solution. They may optionally be applied to the skin in the form of an aerosol. They may also be in solid form, for example in the form of a stick.

They may also be in anhydrous form, in particular in the form of an anhydrous stick. The composition used- according to the invention may also contain other fatty substances.

As oils which can be_^ used in the composition of the invention, mention may be made for example of: - hydrocarbon-based oils of animal origin, such as perhydrosqualene;

- hydrocarbon-based oils of plant origin, such as liquid triglycerides of fatty acids containing from 4 to 10 carbon atoms, such as heptanoic or octanoic- acid triglycerides or alternatively,. for example, sunflower oil, corn oil, soybean oil, marrow oil, grapeseed oil, sesame oil, hazelnut oil, apricot oil, macadamia oil, arara oil, sunflower oil, castor oil, avocado oil, caprylic capric acid triglycerides such as those sold by the company Stearineries Dubois or those sold under the names Miglyol 810, 812 and 818 by the company Dynamit Nobel, jojoba oil or karite butter;

- synthetic esters and ethers, in particular of fatty acids, such as the oils of formulae R¹COOR² and R¹0R² in which R¹ represents a fatty acid residue containing from 8 to 29 carbon atoms and R² represents a branched or unbranched hydrocarbon-based chain containing from 3 to 30 carbon atoms, such as, for example, purcellin oil, isononyl isononanoate, isopropyl myristate, 2-ethylhexyl palmitate, 2-octyldodecyl stearate, '2-octyldodecyl erucate or isostearyl isostearate; hydroxylated esters such as isostearyl lactate, octyl hydroxystearate, octyldodecyl hydroxystearate, diisostearyl malate, triisocetyl citrate, and fatty alcohol heptanoates, octanoates and decanoates; polyol esters such as propylene glycol dioctanoate, neopentyl glycol diheptanoate and diethylene glycol diisononanoate; and pentaerythritol esters such as pentaerythrityl tetraisostearate;

- linear or branched hydrocarbons of mineral or synthetic origin, such as volatile or non-volatile liquid paraffins and derivatives thereof, petroleum jelly, polydecenes, hydrogenated polyisobutene such as parleam oil;

- fatty alcohols containing from 8 to 26 carbon atoms, such as cetyl alcohol, stearyl alcohol, and the mixture of cetyl alcohol and of stearyl alcohol (cetylstearyl alcohol) , Guerbet alcohols such as octyldodecanol and 2-hexyldecanol, 2-butyloctanol, 2-hexyldecanol, 2-undecylpentadecanol, oleyl alcohol or linoleyl alcohol;

- partially hydrocarbon-based and/or silicone-based fluoro oils such as those described in document JP-A-2-295912;

- silicone oils such as volatile or non-volatile polydimethylsiloxanes (PDMSs) containing a linear or cyclic silicone chain, which are liquid or pasty at room temperature, in particular cyclopolydimethylsiloxanes (cyclomethicones) such as cyclohexasiloxane; polydimethylsiloxanes comprising alkyl, alkoxy or phenyl groups, pendent or at the end of a silicone chain, these groups containing from 2 to 24 carbon atoms; phenylsilicones such as phenyl trimethicones, phenyl dimethicones, phenyltrimethylsiloxydiphenylsiloxanes, diphenyl dimethicones, diphenylmethyldiphenyltrisiloxanes, 2-phenylethyl trimethylsiloxysilicates and polymethylphenylsiloxanes ; - mixtures thereof. The term "hydrocarbon-based oil" in the list of the abovementioned oils embraces any oil comprising predominantly carbon and hydrogen atoms, and optionally ester, ether, fluoro, carboxylic acid and/or alcohol groups . The other fatty substances which may be present in the oily phase are, for example, fatty acids containing from 8 to 30 carbon atoms, for instance stearic acid, lauric acid, palmitic acid and oleic acid; waxes, for example lanolin, beeswax, carnauba wax, candelilla wax, paraffin wax, lignite wax or macrocrystalline waxes, ceresine or ozokerite, synthetic waxes, for instance polyethylene waxes and Fischer-Tropsch waxes; silicone resins such as trifluoromethyl-Cι_-alkyldimethicone and trifluoro- propyldimethicone; and silicone elastomers, for instance the products sold under the names "KSG" by the company Shin-Etsu, under the names "Trefil", "BY29" or "EPSX" by the company Dow Corning or under the name "Gransil" by the company Grant Industries. These fatty substances may be chosen in a varied manner by a person skilled in the art in order to prepare a composition having the desired properties, for example consistency or texture properties.

According to one particular embodiment of the invention, the composition according to the invention is a water-in- oil (W/0) or oil-in-water (0/W) emulsion. The proportion of oily phase of the emulsion may range from 5% to 80% by weight and preferably from 5% to 50% by weight relative to the total weight of the composition.

The emulsions generally contain at least one emulsifier chosen from amphoteric, anionic, cationic and nonionic emulsifiers, used alone or as a mixture, and optionally a co-emulsifier . The emulsifiers are chosen in an appropriate manner depending on the emulsion to be obtained (W/0 or O/W) . The emulsifier and the co-emulsifier are generally present in the composition in a proportion ranging from 0.3% to 30% by weight and preferably from 0.5% to 20% by weight relative to the total weight of the composition. Examples of emulsifiers that may be mentioned for the W/0 emulsions include dimethicone copolyols such as the mixture of cyclomethicone and of dimethicone copolyol, sold under the name "DC 5225' C" by the company Dow Corning, and alkyldimethicone copolyols, such as the laurylmethicone copolyol sold under the name "Dow Corning 5200 Formulation Aid" by the company Dow Corning, and the cetyldimethicone copolyol sold under the name Abil EM 90" by the company Goldschmidt. Surfactants of W/0 emulsions that may also be used include a crosslinked elastomeric solid organopolysiloxane comprising^' at least one oxyalkylenated group, such as those obtained according to the procedure of Examples 3, 4 and 8 of document US-A-5 412 004 and the examples of document US-A-5 811 487, especially the product of Example 3 (synthesis example) of patent US-A-5 412 004, such as the product sold under the reference KSG 21 by the company Shin Etsu.

For the O/W emulsions, examples of emulsifiers that' may be mentioned include nonionic emulsifiers such as oxyalkylenated fatty acid esters of sorbitan and of glycerol; oxyalkylenated (oxyethylenated and/or oxypropylenated) fatty alcohol ethers; sugar esters, for instance sucrose stearate; and mixtures thereof.

In a known manner, the cosmetic or dermatological composition of the invention may also contain adjuvants that are common in cosmetics or dermatology, such as active agents, antioxidants, hydrophilic or lipophilic gelling agents, solvents, fragrances, fillers, UV-s^'creening agents, odour absorbers, dyestuffs, plant extracts and salts. The amounts of these various adjuvants are those conventionally used in the field under consideration, for example from 0.01% to 20% relative to the total weight of the composition. Depending on their nature, these adjuvants may be introduced into the fatty phase, into the aqueous phase and/or into lipid spherules.

As fillers that may be used in the- composition of the invention, examples that may be mentioned, besides pigments, include silica powder; talc; polyamide particles, especially those sold under the name Orgasol by the company Atochem; polyethylene powders; microspheres based on acrylic copolymers, such as those based on ethylene glycol dimethacrylate/lauryl methacrylate copolymer sold by the company Dow Corning under the name Polytrap; expanded powders such as hollow microspheres, and especially the microspheres sold under the name Expancel by the company Kemanord Plast, or under the name Micropearl F 80 ED by the company Matsumoto; silicone resin microbeads such as those sold under ^' the name Tospearl by the company Toshiba Silicone; and mixtures thereof.

It is also possible to incorporate fibres, which may be fibres of synthetic or natural, mineral or organic _^origin. The fibres^' may be those used in the manufacture of textiles, and especially silk fibres, cotton fibres, wool fibres, flax fibres, cellulose fibres extracted especially from wood, from vegetables or from algae, polyamide fibres (Nylon®, especially under • the names nylon 6 = polyamide 6; nylon 6, 6 = polyamide 6,6; nylon 12 = polyamide 12), rayon fibres, viscose fibres, acetate fibres, especially rayon acetate, cellulose acetate or silk acetate fibres, poly-p- phenyleneterephthamide fibres, especially Kevlar® fibres, acrylic fibres, especially polymethyl methacrylate or poly (2-hydroxyethyl methacrylate) fibres, polyolefin fibres, especially polyethylene fibres or polypropylene fibres, glass fibres, silica fibres, aramid fibres, carbon fibres, especially in graphite form, Teflon® fibres, insoluble collagen fibres, polyester fibres, polyvinyl chloride fibres, polyvinylidene chloride fibres, polyvinyl alcohol fibres, polyacrylonitrile fibres, chitosan fibres, polyurethane fibres, polyethylene phthalate fibres, fibres formed from a blend of polymers such as those mentioned above, for instance polyamide/polyester fibres, and mixtures of these fibres. These fillers may be present in amounts ranging from 0 to 20% by weight and preferably from 1% to 10% by weight relative to the total weight of the composition.

According to one preferred embodiment, the compositions used in accordance with the invention may also comprise at least one UVA-active and/or UVB-active organic photoprotective agent and/or at least one mineral photo- protective agent (absorbers), which are water-soluble or liposoluble, or even insoluble in the cosmetic solvents commonly used. The organic photoprotective agents are chosen especially from anthranilates; cinnamic derivatives; dibenzoylmethane derivatives; salicylic derivatives, camphor derivatives; triazine derivatives such as those described in _ypatent applications US 4 367 390, EP 863 145, EP 517 104, EP 570 838, EP 796 851, EP 775 698, EP 878 469, EP 933 376, EP 507 691, EP 507 692, EP 790 243 and EP 944 624; benzophenone derivatives; β, β-diphenylacrylate derivatives; benzotriazole derivatives; benzalmalonate derivatives; benzimidazole derivatives; imidazolines; bis-benzazolyl derivatives as described in patents EP 669 323 and US 2 463 264; p-aminobenzoic acid (PABA) derivatives; methylenebis (hydroxyphenylbenzotriazole) derivatives as described in patent applications US 5 237 071, US 5 166 355, GB 2 303 549, DE 197 26 184 and EP 893 119; screening polymers and screening silicones such as those described especially in patent application WO 93/04665; di ers derived from α-alkylstyrene, such as those described in patent application DE 198 55 649; 4, 4-diarylbutadienes as described in patent applications - EP 0 967 200, DE 197 46 654, DE 197 55 649, EP-A-1 008 586, EP 1 133 980^" and EP 133 981, and mixtures thereof.

The photoprotective agents are generally present in the compositions according to the invention ^' in proportions ranging from 0.1% to 20% by weight relative to the total weight of the composition, and preferably ranging from 0.2% to 15% by weight relative to the total weight of the composition.

The compositions according to the invention may optionally contain one or more thickening compounds, in concentrations preferably ranging from 0.05% to 2% 'by weight relative to the total weight of the composition.

As examples of thickening compounds that may be used in the composition of the invention, mention .may be made of: - polysaccharide biopolymers, for instance xanthan gum, guar gum, alginates and modified celluloses;

- synthetic polymers, such as polyacrylics, for instance

Carbopol 980 sold by the company Goodrich-;' .and acrylate/acrylonitrile copolymers such as Hypan SS201 sold by the company Kingston; mineral compounds such as modified or unmodified smectites and hectorites, such as the Bentone products sold by the company Rheox, the Laponite products sold by the company Southern Clay Products, or the product Veegum HS sold by the company R.T. Vanderbilt; and mixtures thereof.

The present invention also relates to a process for dissolving at least one coumarin derivative, comprising the step consisting in mixing it with at , least one amino acid ester of formula (III) :

R'ι(CO)N(R'₂)CH(R'₃) (CH₂) _n (CO) OR' ₄ (III) in which: n is an .integer equal to 0, 1 or 2,

R' i represents a linear or branched C₅- to C₂₁' alkyl or alkenyl radical,

R'₂ represents a hydrogen atom or a Ci to C₃ alkyl group,

R' ₃ represents a radical chosen from the group formed by a hydrogen atom, a methyl group, an ethyl group and a linear or branched C₃ or C₄ alkyl radical, R' ₄ represents a linear or branched C_x to Cχo alkyl radical, a linear or branched C₂ to Cι₀ alkenyl radical, or a sterol residue.

A subject of the invention is also a cosmetic treatment process for combating cellulite, characterized in that it comprises the application of a composition according to the invention to the skin.

The invention also relates to a cosmetic treatment process for combating the formation of bags and/or shadows under the eyes, characterized in that it comprises the application of a composition according to the invention to the skin.

According to one preferred embodiment of the invention, the ratio: coumarin derivative/amino acid ester, is between 0.001/99.999 and 30/70 and better still between 0.001/99.999 and 25/75.

The examples that follow illustrate the invention without limiting its scope. Depending on the case, the compounds are cited as chemical names or as CTFA names (International Cosmetic Ingredient Dictionary and Handbook) .

Example 1 : Solubility: Protocol :

The coumarin derivatives are weighed out and placed in a hermetic pill bottle. The required amount of lipophilic amino acid derivative (solubilizer) is added.. The suspension is brought to 80 °C and stirred by magnetic stirring for one hour. The dissolution or non-dissolution of the coumarin derivative and its change over time are then monitored.

The insolubility of the coumarin derivative in the solubilizer is characterized macroscopically by a precipitate or just a cloudy solution, and microscopically by the presence of crystals. Resul ts :

A test conducted with isopropyl N-lauroylsarcosinate as lipophilic amino acid derivative made it possible to dissolve up to 20% by weight of visnadine (the remainder of the solution consisting of the solubilizer) . For comparative purposes, using a Cχ₂-Ci5 alkyl benz,oate as solubilizer, the results led to the dissolution of at most 15% visnadine. Other solvents such as water, glycerol, liquid paraffin or isopropyl palmitate do not allow this coumarin derivative to be dissolved.

Example 2 : Formulation examples : Several examples were performed in different types of emulsion.

Example A: Emulsion based on sugar esters :

Phase A: ammonium polyacryloyldimethyl taurate 1.5% sodium hyaluronate 0.1% glycerol 5% preserving agent 0.4% water qs 100%

Phase B: PEG 120 methyl glucose dioleate 0.5% polysorbate 20 0.5% isopropyl N-lauroylsarcosinate 15% visnadine 2%

Phase C: ethanol 5%

Comparative Example A' :

Phase B: PEG 120 methyl glucose dioleate 0.5% polysorbate 20 0.5%

Cs-Cio triglyceride 10% visnadine 2%

Phase C: ethanol .5% Procedure :

The aqueous phase A is prepared by mixing together the various constituents and homogenizing. Phase B is prepared by adding the premix of visnadine and of solubilizer to the surfactant mixture. Phase A is then added to phase B at a temperature of 75 °C. Phase C is then added at a temperature of 25°C to the mixture obtained.

-Sxaiqple B: Emulsified gel

Phase A: acrylates/C₁₀-₃o alkyl acrylate crosspolymer 0.25% xanthan 0.3% glycerol 3%

PEG-8 3% base 0.15% preserving agent 0.1% water qs 100%

Phase B: volatile silicone 10% isopropyl N-lauroylsarcosinate 15% visnadine 2%

Phase C: ethanol 15% silicone polymer 2%

Comparative Example B ^r :

Phase A: acrylates/Cι₀-₃₀ alkyl acrylate crosspolymer 0.25% xanthan 0.3% glycerol 3%

PEG-8 3% base 0.15% preserving agent 0.1% water qs 100%

Phase B: volatile silicone 10%'

C₈-Cιo triglyceride 10% visnadine 2%

Phase C: ethanol 15% silicone polymer 2%

Procedure:

Phase A is prepared by homogenizing the various constituents. The premix of visnadine and of solubilizer is added to the other constituents of phase B. Phase B is added to phase A at a temperature of 75 °C. Phase C is then added to the mixture obtained at a temperature of 25°C.

Example C: Emulsion based on glycerol esters and sorbitan esters

Phase A: glyceryl stearate (and), ■PEG-100 stearate ^• 2.5% polysorbate 60 2.5% cetyl alcohol 1% stearyl alcohol 1% paraffin 5% preserving agent 0.1% isopropyl N-lauroylsarcosinate 15% visnadine 2%

Phase B: preserving agent 0.2% carbomer 0.3% base 0.2% water qs 100%

Comparative Example C;

Phase A: glyceryl stearate (and) PEG- -100 stearate __- • "6 polysorbate 60 *-- ■ D "6 cetyl alcohol 1% stearyl alcohol 1% paraffin 5% preserving agent 0.1%

C₈-Cιo triglyceride 10% visnadine 2%

Phase B: preserving agent 0.2% carbomer 0.3% base 0.2% water qs 100%

Example D: Fluid emulsion :

Phase A: carbomer 0.2% preserving agent 0.65% acrylates/Cιo-₃o alkyl acrylate crosspolymer 0.2% glycerol 3% antioxidant 0.3% xanthan 0.2% base 0.2% water qs 100%

Phase B: cyclohexasiloxane 5% isopropyl N-lauroylsarcosinate 19% visnadine 2%

Phase C: dimethicone copolyol 5%

Phase D: polyacrylamide (and) Cι₃-Cι isoparaffin (and) Laureth-7 0.4%

Phase E: ethanol 5%

Procedure : Phase A is prepared by homogenizing the various constituents. The premix of visnadine and solubilizer is added to the other constituent of the oily phase B. Phase B is added to phase A at a temperature of 30°C. Next, phases C, D and E are successively added. Example E: Emulsified gel

Phase A: acrylates/Cι₀-₃o^' alkyl acrylate crosspolymer 0.25% xanthan 0.3% glycerol 3% propylene glycol 3%

PEG-8 3% base 0.15% preserving agent 0.1% water qs 100%

Phase B: volatile silicone 10% isopropyl N-lauroylsarcosinate 15% visnadine 1%-

Phase C: ethanol 15% silicone polymer 2%

The procedure is identical to that used for the preparation of Example B.

Example F: Emulsion

Phase A: glyceryl stearate (and) PEG-100 stearate 2.5% polysorbate 60 2.5% cetyl alcohol 1% stearyl alcohol 1% paraffin 5% preserving agent 0.1% isopropyl N-lauroylsarcosinate 15% visnadine 1%

Phase B:' preserving agent 0.2% carbomer 0.3% base 0.2% water qs 100% The procedure is identical to that used for the preparation of Example C.

Example G:

Phase A: glyceryl stearate (and) PEG-100 stearate 2.5% polysorbate 60 2.5% cetyl alcohol 1% stearyl alcohol 1% retinol 0.08% soybean oil 1% paraffin 5% preserving agent 0.1% isopropyl N-lauroylsarcosinate 15% visnadine 1%

Phase B: preserving agent 0.2% carbomer 0.3% base 0.2% water ^• qs 100%

The procedure is identical to that used for the preparation of Example C.

Example H:

Phase A: glyceryl stearate (and) PEG- -100 stearate 2.5% polysorbate 60 -^ ■ "6 cetyl alcohol 1% stearyl alcohol 1% paraffin 5% preserving agent 0.1% isopropyl N-lauroylsarcosinate 15% esculoside 1% : Phase B: preserving agent 0.2% carbomer 0.3% base 0.2% water qs 100%

The procedure is identical to that used for the preparation of Example C.

Example 3 : Stability control :

The pH (at 25°C) and the viscosity (Rheomat 180 at 25°C, 200 s^"1) of the compositions of the above examples were measured, along with the microscopic and macroscopic aspects, at T = 0, T = 24 hours and at T = 2 months at 45°C. The results are collated in the table below:

The above stability tests show that the amino acid ester used according to the invention allows excellent- solubilization of the coumarin derivatives and the production of a cosmetic composition that is entirely satisfactory in terms of both stability and cosmetic feel.

Claims

1. Cosmetic composition comprising, in a physiologically acceptable medium, at least one coumarin derivative and at least one lipophilic amino acid derivative.

2. Composition according to Claim 1, characterized in that the coumarin derivative is chosen from unsubstituted coumarins, monosubstituted coumarins and disubstituted coumarins, and/or mixtures thereof, their optional enantiomers, diastereoisomers, or mixtures thereof, including racemic mixtures.

3. Composition according to either of Claims 1 and 2, characterized in that the coumarin derivative is chosen from the bicyclic coumarins represented by formula (I) :

in which R represents a hydrogen atom or a linear or branched, saturated or unsaturated alkyl group containing from 1 to 20 carbon atoms, which is optionally hydroxylated, and one carbon atom of which may be replaced with a hetero atom chosen from oxygen, nitrogen and sulphur atoms; and Ri and R₂ independently represent a hydrogen atom or a group chosen from R₃₀, -0-R₃χ, -N-R₃χR₃₂, -C0-R₃ι and -0-C0-R₃o, in which:

R₃₀ represents a group chosen from linear or branched, saturated or unsaturated alkyl groups containing frpm 1 to 20 carbon atoms, optionally hydroxylated, and one ycarbon atom of which may be replaced with a hetero atom chosen from oxygen, nitrogen and sulphur atoms; cycloalkyl containing from 3 to 8 carbon atoms, optionally hydroxylated, and one carbon atom of which may be replaced with a hetero atom chosen from oxygen, nitrogen and sulphur atoms; optionally substituted aryl; 5- to 11-membered monocyclic or bicyclic heteroaryl containing at least one aromatic ring, and containing from 1- to 5 hetero atoms chosen from nitrogen, oxygen and sulphur, optionally substituted; an arylalkyl group in which the aryl and alkyl radicals have the same meaning as above; and heteroarylalkyl in which the heteroaryl and alkyl radicals have the same meaning as above; and a sugar residue; R₃ι and R₃₂ independently represent a hydrogen atom or a group R₃₀, their optional enantiomers, diastereoisomers, or mixtures thereof, including racemic mixtures.

4. Composition according to Claim 3, characterized in that the group R represents a hydrogen atom or a linear or branched alkyl group containing from 1 to 6 carbon atoms, and the groups Ri and R₂ independently represent a group - O-R₃₁ in which R₃₁ is chosen from a hydrogen atom; a linear or branched, saturated or unsaturated alkyl group containing from 1 to 20 carbon atoms, optionally hydroxylated, and one carbon atom of which may be replaced with a hetero atom chosen from oxygen, nitrogen and sulphur atoms; and a sugar residue.

5. Composition according to one of Claims 1 to 3, characterized in that the coumarin derivative is esculoside, of formula:

6. Composition according to one of Claims 1 to 3, characterized in that the coumarin derivative is methylesculetin, of formula:

7. Composition according to either of Claims 1 and 2, characterized in that the coumarin derivative is chosen from the tricyclic coumarins of formula (II) :

in which R₄ and R₅ independently represent an alkyl group containing from 1 to 6 carbon atoms, and

R₆ and R₇ independently represent a hydrogen atom or a group chosen from R₆₀, -0-R₆χ, -N-R₆ιR62-- -CO-R₆ι or -0-CO-R₆OΛ in which: Rεo represents a group chosen from linear or branched, saturated or unsaturated alkyl groups containing from 1 to , 20 carbon atoms, optionally hydroxylated, and one carbon atom of which may be replaced with a hetero atom chosen from oxygen, nitrogen and sulphur atoms; cycloalkyl containing from 3 to 8 carbon atoms, optionally 5 hydroxylated, and one carbon atom of which may be replaced with a hetero atom chosen from oxygen, nitrogen and sulphur atoms; optionally substituted aryl; 5- to 11-membered monocyclic or bicyclic heteroaryl containing at least one aromatic ring, and containing from 1 to 5 hetero atoms

10 chosen from nitrogen, oxygen and sulphur, optionally substituted; an arylalkyl group in which the aryl and alkyl radicals have the ' same meaning as above; and heteroarylalkyl in which the heteroaryl and alkyl radicals have the same meaning as above; and a sugar residue;

15 Rβi and Rβ₂ independently represent a hydrogen atom or a group Reo, their optional enantiomers, diastereoisomers, or mixtures thereof, including racemic mixtures.

8. Composition according to Claim 7, characterized in 20. that the groups R₄ and R5 each represent a methyl group.

9. Composition according to Claim 7, characterized in that the groups Rζ and R independently represent a group - O-CO-Rδi in which R₆ι represents a linear or branched,

25 saturated or unsaturated alkyl group containing from 1 to 20 carbon atoms, optionally hydroxylated, and one carbon atom of which may be replaced with a hetero atom chosen from oxygen, nitrogen and sulphur atoms.

30 10. Composition according to one of Claims 7 to 9, characterized in that the coumarin derivative is visnadine, of formula:

11. Composition according to Claim 1, characterized in that the lipophilic amino acid derivative is an ester chosen from the amino acid esters of formula (III) : R'i(CO)N(R'₂)CH(R'₃) (CH₂) _n (CO) OR' ₄ (III) in which: n is an integer equal to 0, 1 or 2,

R' i represents a linear or branched C₅ to C₂χ alkyl or alkenyl radical,

R'₂ represents a hydrogen atom or a Ci to C₃ alkyl group,

R' ₃ represents a radical chosen from the group formed by a hydrogen atom, a methyl group, an ethyl group and a linear or branched C₃ or C₄ alkyl radical,

R'₄ represents a linear or branched Ci to Cio alkyl radical, a linear or branched C₂ to Cι₀ alkenyl radical or a sterol residue.

12. Composition according to Claim 11, characterized in that the said amino acid ester is isopropyl N- lauroylsarcosinate :

CH₃- (CH₂) ₁₀CO-N (CH₃) -CH₂-COO-CH (CH₃) ₂ •

13. Composition according to any one of Claims 1 to 12, characterized in that the said coumarin derivative represents from 0.001% to 30%, preferably from 0.001% to 20% and even more preferably from 0.1% to 5% by weight relative to the total weight of the composition.

14. Composition according to any one of Claims 1 to 13, characterized in that the said lipophilic amino acid derivative represents from 0.01% to 90% by weight and preferably from 0.1% to 30% by weight relative to the total weight of the composition.

15. Use of a composition according to one of Claims 1 to 14, as a slimming composition and/or a composition for combating cellulite.

16. Use of a composition according to one of Claims 1 to 14, for combating the formation of bags and/or shadows under the eyes.

17. Cosmetic treatment process for combating cellulite, characterized in that it comprises the application of a composition according to any one of Claims 1 to 14 to the skin.

18. Cosmetic treatment process for combating the formation of bags and/or shadows under the eyes, characterized in that it comprises the application of a composition according to any one of Claims 1 to 14 to the skin.

19. Process for dissolving at least one coumarin derivative, comprising the step of mixing it with at least one amino acid ester of formula (III) : R'ι(CO)N(R'₂)CH(R'₃) (CH₂) _n (CO) OR' ₄ (III) in which: n is an integer equal to 0, 1 or 2,

R'ι represents a linear or branched C₅ to C₂ι alkyl or alkenyl radical,

R'₂ represents a hydrogen atom or a Ci to -C^ alkyl group, R' ₃ represents a radical chosen from the group formed by a hydrogen atom, a methyl group, an ethyl group and a linear or branched C₃ or C₄ alkyl radical, R^f ₄ represents a linear or branched Ci to Cχo alkyl radical, a linear or branched C₂ to Cio alkenyl radical, or a sterol residue.

20. Process according to Claim 19, characterized in that the ratio: coumarin derivative/ amino acid ester, is between 0.001/99.999 and 30/70 and preferably between 0.001/99.999 and 25/75.