MXPA01005460A - Method for improving uv radiation stability of photosensitive sunscreen filters - Google Patents

Abstract

The invention concerns a method for improving the UV radiation stability of a photosensitve sunscreen filter, which consists in incorporating said filter in a substance produced by sol-gel process from at least a silicon alkoxide and at least a surfactant. The invention also concerns a photostable substance comprising in combination a sunscreen filter and a light stabilizing substance produced by sol-gel process containing at least a silicon alkoxide and at least a non-ionic surfactant, and a cosmetic and/or dermatological composition comprising in a cosmetically and/or dermatologically acceptable support, an efficient amount of a photostable substance. Said cosmetic and/or dermatological composition is particularly designed to protect the skin and/or keratinous materials, against ultraviolet radiation.

Description

PROCESS TO IMPROVE STABILITY AGAINST RADIATION OF ULTRAVIOLET LIGHT OF SOLAR FILTERS PHOTOSENSIBLES Description of the invention The present invention relates to a process for improving the stability against UV radiation of a solar filter sensitive to UV radiation. It also refers to the photo-stable material, as well as to a cosmetic and / or dermatological combination containing such material. It is said that luminous radiations of wavelengths between 280 nm and 400 nm allow the darkening of the human epidermis, and that rays of wavelengths between 280 and 320 nm, known under the name of UV-B, cause erythema and skin burns that can impair the development of natural tanning; therefore this UV-B radiation must be filtered. It is also said that UV-A rays, with wavelengths comprised between 320 and 400, which cause the skin to darken, are susceptible to induce an alteration of the same, in particular in the case of a sensitive skin or a skin continuously exposed to solar radiation. UV-A rays are more penetrating than UV-B rays and cause in particular a loss of Ref: 129659 skin elasticity and the appearance of wrinkles that lead to premature aging. They favor the triggering of the erythematous reaction, or amplify this reaction in certain subjects and can also be the origin of phototoxic or photoallergic reactions. Therefore it is also desirable to filter UV-A radiation. Thus, in order to ensure protection of the skin and keratin materials against UV radiation, sunscreen compositions containing UV-A active filters and UV-B active filters are generally used. In this perspective, a well-known family of UV-A active filters, and particularly interesting, is constituted by the dibenzoylmethane derivatives and in particular, 4-t-butyl-4'-methoxydibenzoylmethane marketed by the company HOFFMAMN-LAROCHE under the denomination "PARSOL® 1789". Also, a particularly interesting family of active filters for UV-B is currently constituted by the cinnamic acid derivatives, and particularly the 2-ethylhexyl p-cinnamate marketed by the company HOFFMANN-LAROCHE under the name "PARSOL® MCX" . However, sunscreens, such as Parsol® 1789 and Parsol® MCX, present a greater problem of sensitivity to UV radiation. Indeed, it happens that the dibenzoylmethane derivatives are relatively sensitive to ultraviolet radiation. They have an unpleasant tendency to degrade more or less rapidly under the action of the latter. Thus, this photochemical sensitivity of the dibenzoylmethane derivatives against the ultraviolet radiation to which they are intended to be subjected by nature, does not guarantee constant protection during a prolonged solar exposure, so that, mandatory, the applications repeated in intervals Regular and approximate time should be made by the user to obtain effective protection of the skin against UV radiation. It is the same for cinnamic acid derivatives. Consequently, it was sought to reduce the sensitivity to UV radiation of these filters (hereinafter referred to by photosensitive filters), but it then conflicts with the numerous formulation problems. For example, a particular photosensitive filter can not be formulated with certain other active products, each time requiring the development of a new formulation. Also, a photosensitive filter can not be formulated with certain other filters, for example, Parsol® 1789 (UV-A filter) and Parsol® MCX (UV-B filter). In addition, these photosensitive sunscreens have a protective effect necessarily limited in time, and to compensate for their sensitivity to UV radiation, important amounts must be included in the formulations without this being enough to solve the problem. This problem of sensitivity to UV radiation from sunscreens is well known to the person skilled in the art. In particular, the patent application of PCT number WO 98/31333 describes the incorporation of a solar filter in a material made by sol-gel (colloidal solution-gel), but this presents the following main drawbacks. The inclusion of the filter in an effective amount in a material as described in the document leads to important incompatibilities in the plane of stability against UV radiation. The Applicant found, surprisingly, that by associating a photosensitive solar filter with a material made by sol-gel, containing at least one silicon alkoxide and at least one surfactant, a material having improved stability against UV radiation is obtained. . The photostable material and the cosmetic and / or dermatological compositions containing an effective amount of this material are capable of forming a film with a pleasant touch and have a very good permanence in water, pure or saline, and in polar cosmetic oils and not polar. The subject of the present invention is therefore a process for improving the stability of a photosensitive filter against UV radiation, comprising the incorporation of the filter into the sol-gel material made from at least one silicon alkoxide and from at least one surfactant. Another objective consists of a photo-stable material containing a photosensitive filter associated with a photostabilising material produced by sol-gel from at least one silicon alkoxide and at least one surfactant. The present invention also aims at a cosmetic and / or dermatological composition containing an effective amount of a photostable material according to the invention. Other features, aspects and advantages of the invention will appear even clearer with the reading of the description and the various examples that follow it. According to the present invention, the process for improving the stability against UV radiation of a photosensitive solar filter comprises the incorporation of the filter into a sol-gel processed material, which includes: (a) at least one alkoxide of silicon chosen among those that respond to one of the following formulas: Yes (OR1) 4 (I) R-Yes OR j (II) (R10) 3-Si-R "-YES (0R1) 3 (III) R-YES (OR1) 2 (IV) wherein: Rx represents a linear or branched alkyl group of C ^ , preferably C1_6, R and R ', independently of one another, represent a linear or branched alkyl group, a cycloalkyl group, an aryl group substituted or not, the groups R and R 'may also contain a cosmetically or dermatologically active group; R "represents a linear or branched alkylene group, a cycloalkylene group, an arylene group substituted or not, the group R" may also contain a cosmetically or dermatologically active group; (b) at least one solvent, (c) at least one surfactant and (d) water Among the cosmetic or dermatologically active groups that can be carried by the groups R, R 'and R ", there can be mentioned, for example, a group dye, a photochromic group, a group that promotes adhesion on keratin materials such as phosphate, phosphonate, amide, urethane, ureide, hydroxy, carboxy, thiol, amino acid or polypeptide groups, an anti-free radical group and a vitamin carrier group Among the silicon alkoxides defined above, tetraethoxysilane and methyltriethoxysilane are particularly preferred in particular The surfactants that can be used in the present invention are all compounds chemically compatible with silicon alkoxide, the solvent and the photosensitive solar filter Preferably, the surfactant is a nonionic surfactant chosen in general among alcohols, alkylphenols or fatty acids. oliethoxylated, polypropoxylated or polyglycerolated, a fatty chain containing from 6 to 32 carbon atoms, preferably from 8 to 18 carbon atoms, the number of ethylene oxide or propylene oxide groups is comprised between 2 and 100, preferably between 2 and 50, and the number of glycerol groups is comprised between 2 and 30. Also copolymers of ethylene and propylene oxides can be cited as nonionic surfactants; the condensates of ethylene and propylene oxides in fatty alcohols; polyethoxylated fatty amides preferably having 2 to 30 moles of ethylene oxide; polyglycerolated fatty amides containing preferably 1 to 5 glycerol groups, and in particular 1.5 to 4; polyethoxylated fatty amines preferably having 2 to 30 moles of ethylene oxide; the esters of sorbitan fatty acids ethoxylated. with 2 to 30 moles of ethylene oxide; sucrose fatty acid esters, polyethylene glycol fatty esters, alkyl polyglucosides, carbamates derivatives or amides of N-alkylglucamines, aldobionamides, amine oxides such as alkylamines or N-acyl amidopropi1-morpholine oxides. Among the surfactants mentioned above, it is preferred to use in particular a polyethoxylated 4- (1,1,3,3-tetramethylbutyl) phenol. The latter is marketed under the name of Triton® XlOO in Rohm & Haas. The amount of surfactant used in the present invention will depend on its solubility in the alkoxide / solvent / water mixture. The weight ratio of the surfactant to silicon alkoxide varies in general from 0.01% to 99%, preferably from 1% to 60%. Among the photosensitive sunscreens usable according to the invention, mention may be made of dibenzoylmethane derivatives and cinnamic acid derivatives. Among the derivatives of dibenzoylmethane, the following may be mentioned without limitation: 2-methyldibenzoylmethane, 4-methyldibenzoylmethane, 4-isopropyldibenzoylmethane, 4-tert-butyldibenzoylmethane, 2,4-dimethyldibenzoylmethane, 2,5-dimethyldibenzoylmethane. , 4,4'-diisopropyldibenzoylmethane, 4,4'-dimethoxydibenzoylmethane, 4-tert-butyl-4'-methoxydibenzoylmethane, 2-methyl-5-isopropyl-4'-methoxydibenzoylmethane, 2-methyl-5- tert-butyl-4'-methoxydibenzoylmethane, 2,4-dimethyl-4'-methoxydibenzoylmethane, - 2,6-dimethyl-4-tert-butyl-4'-methoxydibenzoylmethane, Among the dibenzoylmethane derivatives mentioned above, is preferred completely in particular according to the present invention, 4-tert-butyl-4'-methoxydibenzoylmethane commercially available under the name PARSOL® 1789 from the company HOFFMAN-LAROCHE. As another photosensitive filter, cinnamic acid derivatives selected among those that respond to the following general formula can be used: wherein: A represents: - a group OR3, R3 is chosen from a hydrogen atom, a phytyl or benzyl group, a linear, branched or cyclic, saturated or unsaturated Ci-Ciß alkyl group, an alkali metal salt or alkaline-earth, an ammonium ion, a group NHR4, R4 is chosen from a hydrogen atom, a phytyl or benzyl group, a linear, branched or cyclic, saturated or unsaturated C de-Cl s alkyl group; R1 represents a group selected from H, OH, C1-C6 alkoxy, preferably methoxy, a C1-C18 alkyl group / linear, branched or cyclic, saturated or unsaturated; R 2 represents a group chosen from H, OH, C 1 C alkoxy, preferably methoxy. Preferably, the photosensitive filter of this family is the 2-ethylhexyl p-cinnamate which is commercially available under the name "PARSOL® MCX" from the company HOFFMANN-LAROCHE. The photosensitive solar filter is present in the sun in an amount ranging from 0.1% by weight up to its solubility limit in the sun, the percentage is expressed with respect to the weight of the silicon alkoxide. Preferably, the photosensitive sunscreen is present in an amount ranging from 0.1% by weight to 10% by weight with respect to the weight of the silicon alkoxide. The solvent used in the present invention is preferably a lower, linear or branched alcohol, better still ethanol. The amount of solvent used in the present invention ranges from 1% by weight to 85% by weight with respect to the weight of the sol. Finally, the amount of water used in the material must be sufficient to obtain a total or partial hydrolysis of the silicon alkoxide. The pH of the hydrolysis water is preferably in the range from 1 to 4, better still in the range from 1 to 2. The present invention also relates to a photostable material containing an associated photosensitive sunscreen to a photo-stabilizing material made by sol-gel including: (a) at least one silicon alkoxide, (b) at least one solvent, (c) at least one nonionic surfactant and (d) water. By photo-stable material is meant a material that has improved stability against UV radiation. All constituents (a), (b), (d) and the photosensitive sunscreen of the photostable material are as described above. The nonionic surfactants which are suitable for the photosensitive material according to the present invention are chosen in particular from alcohols, alkylphenols or polyethoxylated, polypropoxylated or polyglycerolated fatty acids, a fatty chain containing from 6 to 32 carbon atoms, preferably from 8 to 18 carbon atoms, the number of ethylene oxide or propylene oxide groups is between 2 and 50 and the number of glycerol groups is between 2 and 30. Copolymers can also be mentioned as nonionic surfactants. of ethylene and propylene oxides; the condensates of ethylene and propylene oxides in fatty alcohols; polyethoxylated fatty amides preferably having 2 to 30 moles of ethylene oxide; polyglycerolated fatty amides containing preferably 1 to 5 glycerol groups, and in particular 1.5 to 4; polyethoxylated fatty amines preferably having 2 to 30 moles of ethylene oxide; sorbitan fatty acid esters ethoxylated with 2 to 30 moles of ethylene oxide; sucrose fatty acid esters, polyethylene glycol fatty acid esters, alkyl polyglucosides, carbamates derivatives or N-alkylglucamine amides, aldobionamides, amine oxides such as alkylamines or N-acylamidopropyl morpholine oxides. Among the surfactants mentioned above, it is preferred to use in particular a polyethoxylated 4- (1,1,3,3-tetramethylbutyl) phenol. The latter is marketed under the name of Triton® XlOO in Rohm & Haas. To obtain preferably the best photostabilization effect, the constituents of the photostable material according to the invention are added in the following manner. The silicon alkoxide is added to a solvent, and then in the order indicated below: (1) the nonionic surfactant (2) the photosensitive sunscreen, and (3) the water. The photostable material thus obtained can be dried and ground, and contacted with another silicon alkoxide and / or a solvent and the water to effect a surface treatment of the powder. Then a supplementary layer is obtained which also improves the stability against UV radiation. A further objective of the present invention is a cosmetic and / or dermatological composition, comprised in a cosmetically or dermatologically acceptable support, an effective amount of a photostable material according to the invention. This cosmetic and / or dermatological composition contains the photostable material according to the invention in an effective amount ranging from 1% by weight to 99% by weight, preferably from 1% by weight to 60% by weight, based on the total weight of the composition. The cosmetic and / or dermatological composition can be presented in the form of a film-capable sol, applied directly on the skin to ensure its protection against ultraviolet radiation. This application can be done, for example, by means of an atomizer. Preferably, the photo-stable material according to the invention is dried and milled, and is added in the form of particles in a cosmetic and / or dermatological composition. The average size of the particles obtained after drying and milling the photostable material is in the range from 0.1 to 50 μmf, preferably from 0.1 to 20 μm, better still from 0.1 to 10 μm «. The cosmetic and / or dermatological compositions visualized by the present invention can, of course, contain one or several complementary sunscreen agents which are UV-A and / or UV-B, water-soluble, liposoluble or insoluble in the commonly used cosmetic solvents, different photosensitive sunscreens defined before. These complementary filters can be chosen in particular from salicylic derivatives, camphor derivatives, triazine derivatives such as those described in patent applications US 4 367 390, EP0863145, EP0517104, EP0570838, EP0796851, EP0775698, EP0878469, EP0933376 and EP0893119 , the benzophenone derivatives, the β, β '-diphenylacrylate derivatives, the benzimidazole derivatives, the methylene-bis (hydroxyphenylbenzotriazole) derivatives such as those described in patent applications US 5 237 071, US 5 166 355, GB 2303549, DE 19726184 and EP0893119, the p-aminobenzoic acid derivatives, the hydrocarbon polymers filters and silicone filters described in the application WO 93/04665, as well as the bis (benzoazolyl) derivatives such as those described in the application EP0669323 and US 2 463 264. As examples of complementary active sunscreens of UV-A- / or UV-B, there may be mentioned: p-aminobenzoic acid, p-aminobenzoate ethoxy side (25 moles), the 2-ethylhexyl p-dimethylaminobenzoate, the N-propoxylated p-aminobenzoate, the glycerol p-aminobenzoate, the homomenthyl salicylate, the 2-ethylhexyl salicylate, the triethanolamine salicylate, the 4-isopropylbenzyl salicylate, menthyl anthranilate, 2-cyano-3, 3-diphenylacrylate 2-ethylhexyl, ethyl 2-cyano-3,3-diphenylacrylate, 2-phenylbenzimidazole-5-sulphonic acid and its salts , 3- (4'-trimethylammonium) -benzylidene-boronan-2-one-methyl-sulfate, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonate, 2-4- dihydroxybenzophenone, 2, 2 ', 4, 4' -tetrahydroxybenzophenone, 2,2 '-dihydroxy-4-4'-dimethoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-methoxy-4- methylbenzophenone, oi- (2-oxoborn-3-ylidene) -tolyl-4-sulfonic acid and its salts, 3- (4 '-sulfo) benzylidene-bornan-2-one and its salts, 3- (4 '-methylbenzylidene) -d, 1-camphor, 3-benzylidene nd, 1-camphor, urocanic acid, 2,4,6-tris- [p- (2'-ethylhexyl-1'-oxycarbonyl) anilino] -1,3, 5-riazine, 2- [(p. - (velvethylamido) anilino] -4,6-bis- [(p- (2'-ethylhexyl-1'-oxycarbonyl) anilino] -1,3,5-triazine, 2,4-bis. { [4- (2-ethylhexyloxy) -2-hydroxy] phenyl} -6- (4-methoxyphenyl) -l, 3,5-triazine (TINOSORB®, CIBA GEIGY), the polymer of N- (2 and 4) - [(2-oxoborn-3-ylidene) methyl-benzyl] -acrylamide, 1,4-bis-benzimidazolyl-phenylene-3, 3 ', 5, 5'-tetra-sulphonic acid and its soluble salts, polyorganosiloxanes with benzalmalonate function, polyorganosiloxanes with benzotriazole function such as Drometrizol-Trisiloxane, [2,2'-methylene-bis [6-2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol] in solubilized form such as, the product sold under the name MIXXIM® BB / 100 by the FAIRMOUNT CHEMICAL Company, or in an insoluble micronized form such as the product sold under the name TINOSORB® M by the company CIBA GEIGY, [2,2'-methylene-bis [6-2H-benzotriazol-2-yl) -4- (methyl) -phenol] in solubilized form such as the product sold under the name MIXXIM® BB / 200 by the Company FAIRMOUNT CHEMICAL. The compounds according to the invention may also contain tanning agents and / or artificial skin darkening (self-tanning agents) such as, for example, dihydroxyacetone (DHA). The cosmetic and / or dermatological compositions according to the invention can also contain pigments or nanopigments (average size of the primary particles: in general between 5 nm and 100 nm, preferably between 10 and 50 m), of coated metal oxides or no, as for example nanopigments of titanium oxide (amorphous or crystallized in the form of rutile and / or anatase), iron, zinc, zirconium or cerium which are all well-known photoprotective agents that operate themselves by physical blockage (reflection and / or diffusion) of UV radiation. The conventional coating agents are also aluminum and / or aluminum stearate. Such nanopigments of metal oxides, covered or not covered, are described in particular in the patent applications EP-A-0 518 772 and EP-A-0 518 773. The compositions according to the present invention may also comprise classical cosmetic adjuvants, chosen in particular from fatty substances, organic solvents, ionic or nonionic thickeners, softeners, antioxidants, anti-free radical agents, opacifiers, stabilizers, emollients, silicones, -hydroxy acids, agents anti-foam, moisturizing agents, vitamins, perfumes, preservatives, surfactants, fillers, sequestrants, polymers, propellants, alkalizing or acidifying agents, dyes or any other ingredient commonly used in the cosmetic domain and / or dermatological, in particular for the manufacture of antisun compositions in the form of emulsions. The fatty substances can be constituted by an oil or a wax or their mixtures. By oil, a liquid compound is understood at room temperature. By wax, it is meant a solid or substantially solid compound at room temperature, and in which the melting point is generally above 35 ° C. As oils, mineral oils (petroleum jelly) can be mentioned; vegetables (sweet almond oil, macadamia oil, black currant seed, jojoba oil); synthetics such as perhydrosqualene, alcohols, acids or fatty esters (such as the benzoate of C12-C15 alcohols sold under the name "Finsolv TN" by the company Finetex, octyl palmitate, isopropyl lanolate, triglycerides of caprylic / caprylic acids), esters and ethoxylated or propoxylated fatty ethers; silicone compounds (cyclomethicone, preferably of .4 or 5 silicon atoms, polydimethylsiloxane or PDMS) or fluorinated, polyalkylenes. As waxy compounds, mention may be made of paraffin, carnauba wax, beeswax, and hydrogenated castor oil. Among the organic solvents, lower alcohols and polyols may be mentioned. Thickeners can be chosen in particular between crosslinked polyacrylic acids, modified or non-modified guar and cellulose gums, such as hydroxypropylated guar gum, methylhydroxyethylcellulose, hydroxypropylmethylcellulose and silicone gums such as, for example, a polydimethylsiloxane derivative.

The cosmetic and / or dermatological compositions according to the invention can be prepared according to techniques well known to the person skilled in the art, in particular those intended for the preparation of oil-in-water or water-in-oil type emulsions. This cosmetic and / or dermatological composition can be present in particular in the form of an emulsion, simple or complex (oil / water, water / oil, oil / water / oil or water / oil / water) such as a cream, a milk, or in the form of a gel or a gel cream, powder, solid stick and optionally packaged in an aerosol and in the form of foam or spray. Preferably, the cosmetic and / or dermatological compositions according to the invention are presented in the form of an oil-in-water emulsion. When it is an emulsion, the aqueous phase thereof may comprise a nonionic vesicular dispersion prepared according to the known processes (Bangham, Standish and Wat ins, J. Mol. Biol. 13, 238 (1965), FR 2 315 991 and FR 2 416 008). The cosmetic and / or dermatological composition according to the invention is used as a protective composition for the skin or keratin materials, against ultraviolet rays, as an antisun composition or as a make-up product. When the cosmetic composition according to the invention is used for the protection of hair, it can be in the form of a shampoo, lotion, gel, emulsion, non-ionic vesicular dispersion, and can constitute, for example, a rinse composition. , to apply before or after shampooing, before or after coloring or discoloration, before, during or after the permanent or straightening, a lotion or a gel for styling or treatment, a lotion or a gel for brushing or waving , a composition of permanent or smoothing, coloring or discoloration of the hair. The examples are given as illustrative of the present invention and are not intended in any way to be limiting.

Example 1 A material is synthesized by sol-gel from Tetraethoxysilane (TEOS) 1.8 g Absolute ethanol 13.6 g Water (HCl 0.01 N) 1.0 g Triton® X-100 0.6 g Parsol® 1789 0.04 g the tetraethoxysiloxane comes from the company Fluka, the Parsol® 1789 is marketed by the company HOFFMANN-LAROCHE, and the Triton® X-100 is marketed by the company Rohm & Haas. The TEOS is added to the ethanol with stirring. Triton® X-100 is added immediately with agitation, and then Parsol® 1789, always with agitation. No incompatibility between the components is observed. The mixture is stirred for 5 minutes. Water (HCl 0.01 N) is added and stirred for 60 minutes at 30 ° C. The mixture is allowed to return to room temperature with stirring. The material is ready to be used.

Example 2 A material is synthesized via sol-gel from Tetraethoxysilane (TEOS) 1.8 g Absolute ethanol 14.43 g Water (0.1 N HCl) 1.5 g Triton® X-100 0.6 g Parsol® 1789 0.05 g Methyltriethoxysilane (MTES) 3.2 g Tetraethoxysiloxane comes from the company Fluka, Parsol® 1789 is marketed by the company HOFFMANN-LAROCHE, Triton® X-100 is marketed by the company Rohm & Haas, and methyltriethoxysilane is marketed by the company Interchim. The TEOS is added to the ethanol with stirring. Triton® X-100 is added immediately with agitation, and then Parsol® 1789, always with agitation. The mixture is stirred for 5 minutes. Water (HCl 0.01 N) is added and the mixture is stirred for 30 minutes at 48 ° C. The mixture is allowed to return to room temperature with stirring. The sun thus obtained is placed in a ventilated stove, at 50 ° C, for 24 hours. A white solid is then obtained which is milled in order to obtain a white powder. In addition, a sun is prepared from the MTES. For this, the MTES, the ethanol and the water are mixed at room temperature and the mixture is stirred for 1 hour at room temperature. Next, 500 mg of the powder obtained earlier is dissolved in this sol prepared from the MTES. This new sun containing the powder is ready to be used.

Tests of stability against UV radiation Tests of stability against the UV radiation of Parsol® 1789 were carried out immediately, irradiating the materials obtained in examples 1 and 2 as well as, for comparison, materials containing the Parsol 1789 but without surfactant. The materials are deposited on glass plates (slides). Films are formed on the plates after evaporation of the volatile compounds from the mixture. The drying time of the films is fast, that is between 1 and 3 minutes.

The films obtained are then irradiated, under the following conditions: UV-A lamp energy = 19 mW / cm2, UV-B lamp energy = 0.6 mW / cm2, Irradiation time = 20 minutes. These conditions correspond to approximately 1 sunny hour. The photodegradation is followed by absorption spectrophotometry or by HPLC. The results are grouped in the following table.

Table MTMS: methyltrimethoxysilane According to this table, the materials according to the present invention have a better stability against UV radiation with respect to materials that do not contain surfactant. In addition, a permanence was observed in the water, pure or saline, and in the polar and non-polar cosmetic oils, of all the materials studied.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (41)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. Process for improving the stability against UV radiation of a photosensitive solar filter, characterized in that it comprises the incorporation of the filter in a light stabilizing material prepared by sol-gel from at least one silicon alkoxide and at least one surfactant. Process according to claim 1, characterized in that the photostabilising material produced by sol-gel comprises at least one silicon alkoxide, at least one surfactant, at least one solvent and water. 3. Process according to claim 1 or 2, characterized in that the silicon alkoxide is chosen from among those that respond to the following formulas: Si (OR 4 (I) R-Si (0R1) 3 (II) (R10) 3 -Yes-R "-YES (0R1) 3 (III) R-Si (ORx) 2 (IV) R 'in which: R-L represents a linear or branched alkyl group of C ^ 30, preferably C ^, -; R and R ', independently of one another, represent a linear or branched alkyl group, a cycloalkyl group, an aryl group substituted or not, the R and R' groups may further contain a cosmetically or dermatologically active group; R "represents a linear or branched alkylene group, a cycloalkylene group, an arylene group substituted or not, the group R" may also contain a cosmetically or dermatologically active group. Process according to any of the preceding claims, characterized in that the silicon alkoxide is selected from the group consisting of tetra-ethoxysilane and methyltriethoxysilane. 5. Process according to any of the preceding claims, characterized in that the surfactant is a nonionic surfactant. 6. Process according to claim 5, characterized in that the nonionic surfactant is chosen from alcohols, alkylphenols or polyethoxylated, polypropoxylated or polyglycerolated fatty acids, a fatty chain containing from 6 to 32 carbon atoms, the number of groups of ethylene oxide, propylene oxide is between 2 and 100 and the number of glycerol groups is between 2 and 30; copolymers of ethylene and prapylene oxides; the condensates of ethylene and propylene oxides in fatty alcohols; the polyethoxylated fatty amides; the polyglycerolated fatty amides; the polyethoxylated fatty amines; the ethoxylated sorbitan fatty acid esters; the fatty acid esters of sucrose or polyethylene glycol; the alkyl polyglucosides; the amide or carbamate derivatives of N-alkylglucamine, the aldobionamides and the amine oxides. Process according to any of the preceding claims, characterized in that the surfactant is a polyethoxylated 4- (1,1,3,3-tetramethylbutyl) phenol. Process according to any of the preceding claims, characterized in that the surfactant is present in an amount ranging from 0.01% to 99% by weight, preferably from 10% to 60% by weight, with respect to the silicon alkoxide. 9. Process according to any of the preceding claims, characterized in that the photosensitive solar filter is chosen from the group consisting of dibenzoylmethane derivatives and cinnamic acid derivatives. Process according to any of the preceding claims, characterized in that the photosensitive filter is chosen from: 2-methyldibenzoylmethane, 4-methyldibenzoylmethane, 4-isopropyldibenzoylmethane, - 4-tert-butyldibenzoylmethane, 2,4-dimethyldibenzoylmethane , 2,5-dimethyldibenzoylmethane, 4,4'-diisopropyldibenzoylmethane, 4,4'-dimethoxydibenzoylmethane, 4-tert-butyl-4'-methoxydibenzoylmethane, 2-methyl-5-isopropyl-4'-methoxydibenzoylmethane, 2-methyl-5-tert-butyl-4'-methoxydibenzoylmethane, 2,4-dimethyl-4'-methoxydibenzoylmethane, 2,6-dimethyl-4-tert-butyl-4'-methoxydibenzoylmethane. 11. Process according to any of the preceding claims, characterized in that the photosensitive solar filter is 4-tert-butyl-4'-methoxydibenzoylmethane. 12. Process according to any of claims 1 to 9, characterized in that the photosensitive solar filter is chosen from the cinnamic acid derivatives that respond to the following general formula: wherein: A represents: a group OR3, R3 is chosen from a hydrogen atom, a phytyl or benzyl group, an alkyl group of linear, branched or cyclic, saturated or unsaturated, an alkali metal or alkaline earth metal salt , an ammonium ion, an NHR4 group, R4 is selected from a hydrogen atom, a phytyl or benzyl group, a linear, branched or cyclic, saturated or unsaturated Ci-C2 alkyl group; R1 represents a group selected from H, OH, linear, branched or cyclic alkoxy, saturated or unsaturated; R2 represents a group selected from H, OH, C ^ C6 alkoxy, preferably methoxy. 13. Process according to claim 12, characterized in that the photosensitive solar filter is 2-ethylhexyl p-cinnamate. Process according to any of the preceding claims, characterized in that the photosensitive solar filter is present in an amount ranging from 0.1% by weight up to its solubility limit in the sol, with respect to the weight of the silicon alkoxide. 15. Process according to any of the preceding claims, characterized in that the photosensitive solar filter is present in an amount ranging from 0.1% by weight to 10% by weight with respect to the total weight of the silicon alkoxide. 16. Process according to any of the preceding claims, characterized in that the solvent is an alcohol. Process according to claim 16, characterized in that the alcohol is a linear or branched lower alcohol. 18. Process according to claim 17, characterized in that the alcohol is ethanol. 19. Process according to any of the preceding claims, characterized in that the solvent is present in an amount ranging from 1 to 85% by weight with respect to the total weight of the material. 20. Process according to any of the preceding claims, characterized in that the pH of the hydrolysis water is in the range from 1 to 4. 21. Process according to any of the preceding claims, characterized in that the pH of the hydrolysis water it is in the range from 1 to 2. 22. Photo-stable material, characterized in that it contains a photosensitive solar filter associated with a photo-stabilizing material prepared by sol-gel which includes: (a) at least one silicon alkoxide, (b) ) at least one solvent, (c) at least one nonionic surfactant and (d) water. 23. Photo-stable material according to claim 22, characterized in that the silicon alkoxide is chosen from among those that correspond to the following formulas: R-SifOR -j (II) (R10) 3-Si-R "-YES (0R1) 3 (III) R-Yes (ORx) 2 (IV) in which: RL represents a linear or branched alkyl group of C? _ 30, preferably of C ^; R and R ', independently of one another, represent a linear or branched alkyl group, a cycloalkyl group, an aryl group substituted or not, the groups R and R 'may further contain a cosmetically or dermatologically active group, R "represents a linear or branched alkylene group, a cycloalkylene group, a group A substituted or unsubstituted arylene, the group R "may also contain a cosmetically or dermatologically active group 24. Photo-stable material according to claim 22 or 23, characterized in that the silicon alkoxide is selected from the group consisting of tetra-ethoxysilane and methyltriethoxysilane 25. Photo material stable according to any of claims 22 to 24, characterized in that the nonionic surfactant is chosen from alcohols, alkylphenols or polyethoxylated, polypro-or polyglycerolated fatty acids, a fatty chain containing from 6 to 32 carbon atoms, number of ethylene oxide groups, propylene oxide is between 2 and 100 and the number of glycerol groups is between 2 and 30; the copolymers of ethylene and propylene oxides; the condensates of ethylene and propylene oxides in fatty alcohols; the polyethoxylated fatty amides; the polyglycerolated fatty amides; the polyethoxylated fatty amines; the ethoxylated sorbitan fatty acid esters; the fatty acid esters of sucrose or polyethylene glycol; the alkyl polyglucosides; the amide or carbamate derivatives of N-alkylglucamine, the aldobionamides and the amine oxides. 26. Photo-stable material according to any of claims 22 to 25, characterized in that the surfactant is a polyethoxylated 4- (1,1,3,3-tetramethylbutyl) phenol. 27. Photo-stable material according to any of claims 22 to 26, characterized in that the photosensitive solar filter is chosen from the group consisting of dibenzoylmethane derivatives and cinnamic acid derivatives. 28. Photo-stable material according to any of claims 22 to 27, characterized in that the photosensitive filter is chosen from: 2-methyldibenzoylmethane, - 4-methyldibenzoylmethane, - 4-isopropyldibenzoylmethane, 4-tert-butyldibenzoylmethane, - 2,4-dimethyldibenzoylmethane, 2,5-dimethyldibenzoylmethane, 4,4'-diisopropyldibenzoylmethane, 4,4'-dimethoxydibenzoylmethane, 4-tert-butyl-4'-methoxydibenzoylmethane, - 2-methyl-5-isopropyl- 4'-methoxydibenzoylmethane, 2-methyl-5-tert-butyl-4'-methoxydibenzoylmethane, - 2,4-dimethyl-4 * -methoxydibenzoylmethane, 2,6-dimethyl-4-tert-butyl-4'-methoxydibenzoylmethane. 29. Photo-stable material according to any of claims 22 to 28, characterized in that the photosensitive solar filter is 4-tert-butyl-4'-methoxydibenzoylmethane. 30. Photo-stable material according to any of claims 22 to 27, characterized in that the photosensitive solar filter is chosen from the cinnamic acid derivatives that respond to the following general formula: wherein: A represents: a group OR3, R3 is chosen from a hydrogen atom, a phytyl or benzyl group, a linear, branched or cyclic, saturated or unsaturated Ci-Cig alkyl group, an alkali metal salt or alkaline earth, an ammonium ion, - a group NHR4, R4 is chosen from a hydrogen atom, a phytyl or benzyl group, a linear, branched or cyclic, saturated or unsaturated C1-Cl alkyl group; R1 represents a group chosen from H, OH, Ci-Cg alkoxy, preferably methoxy, a C1-C18 alkyl group / linear, branched or cyclic, saturated or unsaturated; R 2 represents a group selected from H, OH, C 1 -C 6 alkoxy, preferably methoxy. 31. Photo-stable material according to claim 30, characterized in that the photosensitive solar filter is the 2-ethylhexyl p-cinnamate. 32. Photo-stable material in accordance with any of the. claims 22 to 31, characterized in that the solvent is an alcohol. 33. Photo-stable material according to claim 32, characterized in that the alcohol is a linear or branched lower alcohol. 34. Photo-stable material according to claim 33, characterized in that the alcohol is ethanol. 35. Photo-stable material according to any of claims 22 to 34, characterized in that the silicon alkoxide is added to a solvent, and then in the following order the non-ionic surfactant, the photosensitive solar filter and the water. 36. Photo-stable material according to claim 35, characterized in that it is dried and milled, and brought into contact with another silicon alkoxide and / or a solvent and water. 37. Cosmetic and / or dermatological composition containing a UV-photosensitive filter, characterized in that it comprises on a cosmetically and / or dermatologically acceptable support, an effective amount of a photostable material according to any of claims 22 to 36. 38 Cosmetic and / or dermatological composition according to claim 37, characterized in that it is also possible to add an additive chosen from sunscreens other than photosensitive sunscreens, tanning agents and / or artificial skin darkening, pigments, bodies fatty, organic solvents, thickeners, softeners and antioxidants. 39. Cosmetic and / or dermatological composition according to claim 37 or 38, characterized in that the photostable material according to any of claims 22 to 36 is added in an effective amount ranging from 1% by weight to 99% by weight , preferably from 1 to 60% by weight with respect to the total weight of the cosmetic and / or dermatological composition. 40. Cosmetic and / or dermatological composition according to any of claims 37 to 39, characterized in that it comprises the photostable material in the form of particles obtained by drying and grinding. 41. Cosmetic and / or dermatological composition according to any of claims 37 to 40, characterized in that the average size of the particles obtained by drying and grinding the photostable material is in the range from 0.1 to 50 μm, preferably from 0.1 to 20 μm.