SILIZIUMHALTIGEN SUBSTITUTED PHOTO STABILIZATION OF A DIBENZOYLMETHANS ON THE BASIS A WITH TWO AMINOBENZOATODER AMINOBENZAMIDGRUPPEN S-TRIAZINS AS WELL AS LIGHT PROTECTION COMPOSITIONS NEW ONE SILIZIUMHALTIGE S-TRIAZINVERBINDUNGEN

The present invention relates to a method for photostabilizing at least one dibenzoylmethane derivative against UV radiation by at least one silicon-containing s-triazine substituted with two aminobenzoate or aminobenzamide groups.

It also relates to novel compositions, in particular cosmetic compositions for topical use containing a combination of a dibenzoylmethane derivative and a silicon-containing s-triazine substituted with two aminobenzoate or aminobenzamide groups.

Light radiation with wavelengths in the range 280 nm to 400 nm is known to brown the human epidermis; more particularly, rays with a wavelength in the range 280 to 320 nm, known as UV-B, are known to cause erythema and cutaneous burns which may be deleterious to the development of a natural tan. For those and for aesthetic reasons, there is a constant demand for means for controlling natural tanning which can thereby control the colour of the skin; that UV-B radiation must therefore be screened.

It is also known that UV-A rays with wavelengths in the range 320 to 400 nm, which cause the skin to brown, tend to induce an impairment in it, in particular with sensitive skin or skin which is continually exposed to solar radiation. In particular, UV-A radiation causes the skin to lose elasticity and the appearance of wrinkles, resulting in premature ageing of the skin. The radiation encourages triggering the erythematous reaction or amplifies that reaction in certain subjects and may even be the cause of phototoxic or photo-allergic reactions. Hence, for aesthetic and cosmetic reasons, such as preserving the natural elasticity of the skin, for example, more and more people would like to control the effect of UV-A radiation on their skin. Thus, screening UV-A radiation is also desirable.

With the aim of ensuring protection of the skin and keratinous material against UV radiation, sunscreen compositions are generally used which comprise organic screens which are active in the UV-A and active in the UV-B regions. The majority of such screens are liposoluble.

In this respect, a current particularly advantageous family of UV-A screens is constituted by dibenzoylmethane derivatives, in particular 4-tert-butyl-4'-methoxydibenzoyl methane, which have intrinsically good absorbing powers. Such dibenzoylmethane derivatives, which are now well known per se as screens which are active in the UV-A region, have been described in French patent applications FR-A-2 326 405 and FR-A-2 440 933, as well as in European patent application EP-A-0 114 607; 4-tert-butyl-4'-methoxydibenzoyl methane is currently marketed under the trade name "Parsol 1789" by ROCHE VITAMINS.

Unfortunately, it has been discovered that dibenzoylmethane derivatives are relatively sensitive to ultraviolet radiation (in particular UV-A), i.e., more precisely, they have an annoying tendency to degrade at a greater or lesser rate under the action thereof. This substantial lack of photochemical stability of dibenzoylmethane derivatives to the ultraviolet radiation to which they are by their very nature intended to be subjected cannot guarantee constant protection during prolonged exposure to the sun, and repeated applications at regular, close intervals have to be made by the consumer to effectively protect the skin against UV radiation.

1,3,5-Triazine derivatives are particularly desirable in solar cosmetics because they are strongly active in the UV-B region. They have in particular been described in the following patents: US-A-4 367 390, EP-A-0 863 145, EP-A-0 517 104, EP-A-0 570 838, EP-A-0 507 691, EP-A-0 796 851, EP-A-0 775 698, EP-A-0 878 469 and EP-A-0 933 376; the following in particular are known:

• 2,4,6-tris[p-(2'-ethylhexyl-1'-oxycarbonyl)anilino]-1,3,5-triazine, or "Ethylhexyl Triazone" (INCI name), sold under the trade name "Uvinul T 150" by BASF;
• 2-[(p-(tertiobutylamido)anilino]-4,6-bis-[(p-(2'-ethylhexyl-1'-oxycarbonyl)anilino]-1,3,5-triazine or "Diethylhexyl Butamido Triazone" (INCI name), sold under the trade name "UVASORB HEB" by SIGMA 3V. They have a strong UV-B absorbing power and it would thus be highly advantageous to be able to use them in combination with the 4-tert-butyl-4'-methoxydibenzoylmethane cited above to obtain products offering broad effective protection over the whole UV radiation range.

However, the Applicant has shown that certain of these 1,3,5-triazine derivatives, when in the presence of 4-tert-butyl-4'-methoxydibenzoylmethane, are photosensitive, namely to UV radiation, and suffer from the disadvantage of undergoing major chemical degradation. Under such conditions, a combination of two screens could no longer provide the skin and hair with prolonged broad-based protection against the sun.

It was proposed in WO02/17873 to use specific bis-resorcinyl triazine compounds to photostabilize a dibenzoylmethane UVA filter. Silicon-containing s-triazine compounds substituted with two aminobenzoate or aminobenzamide groups have been disclosed in EP841341.

The Applicant has now surprisingly discovered a particular family of silicon-containing s-triazine compounds substituted with two aminobenzoate or aminobenzamide groups, which are active in the UV-B region, which can on the one hand substantially improve the photochemical stability (or photostability) of dibenzoylmethane derivatives. On the other hand, such particular s-triazine compounds are photostable even in the presence of a dibenzoylmethane derivative.

These discoveries form the basis of the present invention.

Thus, in accordance with one aspect of the present invention, we now propose a method for improving the stability of at least one dibenzoylmethane derivative against UV radiation, consisting of combining with said dibenzoylmethane derivative at least one s-triazine compound with formula (1) the definition of which will be given below.

In a further aspect, the invention also concerns a composition comprising at least one UV screening system in a physiologically acceptable support, characterized in that it comprises at least:

1. (a) at least one UV screen of the dibenzoylmethane derivative type; and
2. (b) at least one s-triazine compound with formula (1) the definition of which will be given below.

Finally, the present invention also pertains to the use of an s-triazine compound with formula (1) the definition of which is given below, in a composition comprising at least one dibenzoylmethane derivative in a physiologically acceptable support to improve the stability of the dibenzoylmethane derivative to UV radiation.

Other characteristics, aspects and advantages of the invention will become apparent from the following detailed description.

Throughout the present description, the term "system screening UV radiation" is intended to mean an agent screening UV radiation constituted either by a single UV radiation-screening organic or mineral compound or a mixture of several UV radiation-screening organic or mineral compounds, for example a mixture comprising a UV-A screen and a UV-B screen.

The term "silicon-containing" means a compound comprising at least one diorganosiloxane group or a silane group in its structure.

Non-limiting examples of dibenzoylmethane derivatives which may be cited include:

• 2-methyldibenzoylmethane;
• 4-methyldibenzoylmethane;
• 4-isopropyldibenzoylmethane;
• 4-tert-butyldibenzoylmethane;
• 2,4-dimethyldibenzoylmethane;
• 2,5-dimethyldibenzoylmethane;
• 4,4'-diisopropyldibenzoylmethane;
• 4,4'-dimethoxydibenzoylmethane;
• 4-tert-butyl-9'-methoxydibenzoylmethane;
• 2-methyl-5-isopropyl-9'-methoxydibenzoylmethane;
• 2-methyl-5-tert-butyl-4'-methoxydibenzoylmethane;
• 2,4-dimethyl-4'-methoxydibenzoylmethane;
• 2,6-dimethyl-4-tert-butyl-4'-methoxydibenzoylmethane.

Of the dibenzoylmethane derivatives mentioned above, 4-isopropyl-dibenzoylmethane will in particular be used, sold under the trade name "EUSOLEX 8020" by MERCK, having the following formula:

More particularly, 4-(tert-butyl)-4'methoxy dibenzoylmethane or Butyl Methoxy Dibenzoylmethane, sold under the trade name "PARASOL 1789" by Roche Vitamins is preferably used; this screen has the following formula:

The dibenzoylmethane derivative or derivatives may be present in the compositions in accordance with the invention in amounts which preferably vary between 0.01% and 20% by weight, more preferably 0.1% to 10% by weight, and more preferably 0.1% to 6% by weight with respect to the total composition weight.

The compounds in accordance with the present invention have the following general formula (1) or one of its tautomeric forms: in which:

• R, which may be identical or different, represent a linear or branched C₁-C₃₀ alkyl radical, optionally halogenated or unsaturated, a C₆-C₁₂ aryl radical, a C₁-C₁₀ alkoxy radical or the trimethylsilyloxy group;
• a = 0 to 3;
• the group D designates an s-triazine compound with the following formula (2): in which:
• X represents -O- or -NR₃-, in which R₃ represents hydrogen or a C₁-C₅ alkyl radical;
• R₁ represents a linear or branched C₁-C₂₀ alkyl radical which is optionally unsaturated and possibly containing a silicon atom, a C₅-C₂₀ cycloalkyl group, optionally substituted with 1 to 3 linear or branched C₁-C₄ alkyl radicals, the group -(CH₂CHR₄-O)_mR₅ or the group -CH₂-CH(OH)-CH₂-O-R₆;
• R₄ represents hydrogen or methyl; the group (C=O)XR₁ possibly being in the position ortho-, meta- or para- to the amino group;
• R₅ represents hydrogen or a C₁-C₈ alkyl group;
• R₆ represents hydrogen or a C₄-C₈ alkyl group;
• m is a whole number from 2 to 20;
• n = 0 to 2;
• R₂, which may be identical or different, represent a hydroxyl radical, a linear or branched C₁-C₈ alkyl radical, a C₁-C₈ alkoxy radical; two R₂ adjacent to the same aromatic ring may together form a dioxyalkylidene group in which the alkylidene group contains 1 or 2 carbon atoms;
• A is a divalent radical selected from methylene, -[CH(Si(CH₃)₃]-, ethylene or a group having one of formulae (3), (4) or (5) below:         (Z)-CH=CH-     (4) in which:
• Z is a linear or branched, saturated or unsaturated C₁-C₁₀ alkylene diradical, optionally substituted with a hydroxyl radical or oxygens and possibly optionally containing an amino group;
• W represents a hydrogen atom, a hydroxyl radical or a linear or branched, saturated or unsaturated C₁-C₈ alkyl radical.

It should be noted that the derivatives with formula (1) may be used in their tautomeric forms and more particularly in the following tautomeric form with formula (1') below: in which the group D' designates an s-triazine compound with the following formula (2'): In addition to units with formula -A-(Si)(R)_a(O)_(3-a)/2, the organosiloxane may comprise units with formula (R)_b-(Si)(O)_(4-b)/2 in which: R has the same meaning as in formula (1); b = 1, 2 or 3.

In formulae (2) and (2') as defined above, the alkyl radicals may be linear or branched, saturated or unsaturated and selected in particular from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-amyl, isoamyl, neopentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl and tert-octyl radicals. Particularly preferably, the alkyl radical is the methyl radical.

Preferred s-triazine derivatives are those which have at least one, more preferably all of the following characteristics in formula (2) or (2'):

• R and R₁ are methyl;
• a = 2;
• X is O;
• R₁ is a C₄-C₅ radical;
• R₂ and R₃ are hydrogen;
• R₄ is H or OH;

The group (C=O)XR₁ is in the position para- to the amino group;

• A is the propyl radical.

Preferably, the s-triazine compounds of the invention are represented by formulae (1a), (1b) or (1c) below: (1c) (D)-Si(R₈)₃ in which:

• (D) has formula (2) as defined above;
• R₇, which may be identical or different, are selected from linear or branched C₁-C₂₀ alkyl radicals, phenyl, 3,3,3-trifluoropropyl and trimethylsilyloxy, at least 80% by number of the R₇ radicals being methyl;
• R₈, which may be identical or different, are selected from linear or branched C₁-C₂₀ alkyl and alkenyl or phenyl radicals;
• (B), which may be identical or different, are selected from R₇ radicals and the radical (D);
• r is a whole number in the range 0 to 200 inclusive;
• s is a whole number from 0 to 50 and if s=0, at least one of the two symbols (B) designates (D);
• u is a whole number from 1 to 10;
• t is a whole number from 0 to 10, it being understood that t+u equals 3 or more, and tautomeric forms thereof.

Linear diorganosiloxanes with formula (1a) are particularly preferred.

Linear or cyclic diorganosiloxanes with formula (1a) or (1b) which fall within the context of the present invention are random oligomers or polymers preferably having at least one, and more preferably all of the following characteristics:

• R₇ is alkyl; more preferably, it is methyl;
• B is preferably methyl (case of linear compounds with formula (1a)).

Particularly preferred examples of compounds with formula (1) which will be cited are the following compounds with formulae (a) to (i) and tautomeric forms thereof: in which r = 8.1

More particularly, the following compound with structure (b) is used: 2,4-bis(n-butyl 4'-diylaminobenzoate)-6-{[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]disiloxanyl]propyl-3-ylamino}-s-triazine:

Certain compounds with formula (1) and their tautomeric forms are known and have been described in European patent EP-A-0 841 341 and others are novel and constitute a further aspect of the invention.

A first family of novel compounds with formula (1) is constituted by those in which in formula (2), the radical X represents NR₃ in which R₃ has the same meaning as indicated above, and tautomeric forms thereof. An example of a compound having said structure which may be cited is 2,4-bis[(1,1,3,3-tetramethylbutyl) 4'-diylaminobenzamide]-6-{[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]disiloxanyl]propyl-3-ylamino}-s-triazine with formula (d) below:

A second family of novel compounds with formula (1) is constituted by those in which in formula (2), the radical X represents O and at least one of the groups (C=O)XR₁ is in the position ortho- to the amino group, and preferably the two groups (C=O)XR₁ are in the position ortho- to the amino group, and tautomeric forms thereof.

A third family of novel compounds with formula (1) is constituted by those with the following formula (1c):         (1c)    (D)-Si(R₈)₃ in which R₈ has the meaning indicated above, and tautomeric forms thereof.

Novel compounds with formula (1) which may also be cited include:

• • 2,4-bis(methyltrimethylsilyl 4'-diylamino-benzoate)-6-{[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]disiloxanyl]propyl-3-yl-amino}-s-triazine with structure (e):
• • 2,4-bis(2-ethylhexyl 2'-hydroxy-4'-diylamino-benzoate)-6-{[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]disiloxanyl]propyl-3-yl-amino}-s-triazine with structure (f):
• • the random derivative with the following formula (g): in which r = 8.1.

The compounds with formula (1) may be obtained in accordance with the following reaction scheme: in which R, R₁, R₂, A, n and a are as defined above and Y represents a halogen, in particular chlorine or bromine.

The reagents may be introduced in any order; 2 equivalents of derivative with formula (6) followed by one equivalent of derivative with formula (7) (pathway I) or 1 equivalent of derivative with formula (7) followed by 2 equivalents of derivative with formula (6) (pathway II).

The above reactions may optionally be carried out in the presence of a solvent (for example: THF, acetone/water for the first step; toluene, xylene or 1,2-dichloroethane for the second step), at a temperature in the range 0°C to 200°C, more particularly 0°C to 20°C for the first step and 50°C to 120°C for the second step and in the presence or absence of a base to capture the acid formed (for example sodium bicarbonate, sodium carbonate, aqueous sodium hydroxide, triethylamine or pyridine). They may also be carried out in a microwave oven in the presence or absence of a solvent (for example: toluene, xylene or 1,2-dichloroethane) or in the presence or absence of 10% of graphite, at a temperature of 50°C to 150°C, at a power of 50-150 watts for a period of 10 to 30 minutes.

When a is equal to 1-3 and R is an alkoxy, polymerization of monomeric alkoxysilane derivatives may be carried out using conventional silicone chemistry methods.

The preparation of amino derivatives of benzoic acid with formula (6) has been described in particular in FR-A-2 151 503. Particularly suitable amino derivatives of benzoic acid for preparing the compounds according to the invention which may be cited are butyl 4-amino benzoate and pentyl 4-aminobenzoate.

Aminated silicones with formula (7) may be obtained from Dow Corning Toray Silicone Co Ltd, such as those with an α,ω-diamino structure such as BY16-853 (viscosity: 30; NH₂ equivalent: 650) or BY16-853B (viscosity: 80; NH₂ equivalent: 2200) or those with pendent group structures, such as BY16-828 (viscosity: 120; NH₂ equivalent: 3500) or BY16-850 (viscosity: 1100; NH₂ equivalent: 4000).

The aminomethyltrimethylsilane sold by Gelest is bis(trimethylsilyl)methylamine (RN 134340-00-4).

Triazine derivatives with formula (1) in accordance with the invention are preferably present in the compositions in accordance with the invention in amounts of 0.01% to 20% by weight, more preferably 0.1% to 10%, more preferably 0.1% to 6% by weight with respect to the total composition weight.

According to the present invention, the triazine derivative or derivatives with formula (1) will be used in a quantity sufficient to obtain a substantial and significant improvement in the photostability of the dibenzoylmethane derivative in a given composition. This minimum quantity of photostabilizing agent to be used may vary depending on the starting quantity of dibenzoylmethane present in the composition and depending on the nature of the cosmetically acceptable support used in the composition. It may be determined without difficulty using a conventional photostability measuring test.

The compositions according to the invention are generally suited for topical application to the skin and thus generally comprise a physiologically acceptable medium, i.e. compatible with the skin and/or integuments (hair, eyelashes, eyebrows, nails). Preferably, it is a cosmetically acceptable medium, i.e. with an agreeable colour, odour and feel which does not generate unacceptable discomfort (smarting, tightness, redness), which may deter the consumer from using that composition.

The compositions in accordance with the invention will preferably comprise other complementary organic or inorganic photoprotective agents which are active in the UV-A and/or UV-B region, which are hydrophilic or lipophilic or even insoluble in the cosmetic solvents in routine use.

The complementary organic photoprotective agents are selected in particular from anthranilates; cinnamic derivatives; salicylic derivatives; camphor derivatives; benzophenone derivatives; β,β-diphenylacrylate derivatives; benzotriazole derivatives; benzalmalonate derivatives; benzimidazole derivatives; imidazolines; bis-benzoazolyl derivatives such as those described in patents EP-A-0 669 323 and US-A-2 463 264; p-aminobenzoic acid (PABA) derivatives; methylene bis-(hydroxyphenyl benzotriazole) derivatives as described in applications US-A-5 237 071, US-A-5 166 355, British patent GB 2 303 549, German patent DE-A-197 26 184 and in EP-A-0 893 119; polymeric screens and silicone screens such as those described in International patent application WO-A-93/04665; dimeric α-alkylstyrene derivatives such as those described in patent application DE-19855649; 4,4-diarylbutadienes as described in applications EP-A-0 0967200, DE19746654, DE19755649, EP-A-1 008 586, EP-A-1 133 980 and EP-A-0 133 981 and mixtures thereof.

Examples of complementary organic photoprotective agents which may be cited are those designated below under their INCI names:

• PABA;
• Ethyl PABA;
• Ethyl Dihydroxypropyl PABA;
• Ethylhexyl Dimethyl PABA, sold in particular under the trade name "ESCALOL 507" by ISP;
• Glyceryl PABA;
• PEG-25 PABA, sold under the trade name "UVINUL P25" by BASF;

• Homosalate, sold under the trade name "Eusolex HMS" by Rona/EM Industries;
• Ethylhexyl Salicylate, sold under the trade name "NEO HELIOPAN OS" by HAARMANN and REIMER;
• Dipropyleneglycol Salicylate, sold under the trade name "DIPSAL" by SCHER;
• TEA Salicylate, sold under the trade name "NEO HELIOPAN TS" by HAARMANN and REIMER;

• Ethylhexyl Methoxycinnamate, sold in particular under the trade name "PARSOL MCX" by HOFFMANN LA ROCHE;
• Isopropyl Methoxy cinnamate;
• Isoamyl Methoxy cinnamate, sold under the trade name "NEO HELIOPAN E 1000" by HAARMANN and REIMER;
• Cinoxate;
• DEA Methoxycinnamate;
• Diisopropyl Methylcinnamate;
• Glyceryl Ethylhexanoate dimethoxycinnamate;

• Octocrylene, sold in particular under the trade name "UVINUL N539" by BASF;
• Etocrylene, sold in particular under the trade name "UVINUL N35" by BASF;

• Benzophenone-1, sold under the trade name "UVINUL 400" by BASF;
• Benzophenone-2, sold under the trade name "UVINUL D50" by BASF;
• Benzophenone-3 or Oxybenzone, sold under the trade name "UVINUL M40" by BASF;
• Benzophenone-4, sold under the trade name "UVINUL MS40" by BASF;
• Benzophenone-5;
• Benzophenone-6, sold under the trade name "Helisorb 11" by Norquay;
• Benzophenone-8, sold under the trade name "Spectra-Sorb UV-24" by American Cyanamid;
• Benzophenone-9, sold under the trade name "UVINUL DS-49" by BASF;
• Benzophenone-12;
• n-Hexyl 2-(9-diethylamino-2-hydroxybenzoyl) benzoate, sold under the trade name "UVINUL A+" by BASF;

• 3-benzylidene camphor made under the trade name "MEXORYL SD" by CHIMEX;
• 4-methyl benzylidene camphor, sold under the trade name "EUSOLEX 6300" by MERCK;
• Benzylidene Camphor Sulfonic Acid, made under the trade name "MEXORYL SL" by CHIMEX;
• Camphor Benzalkonium Methosulfate, made under the trade name "MEXORYL SO" by CHIMEX;
• Terephthalylidene Dicamphor Sulfonic Acid, made under the trade name "MEXORYL SX" by CHIMEX;
• Polyacrylamidomethyl Benzylidene Camphor, made under the trade name "MEXORYL SW" by CHIMEX;

• Phenylbenzimidazole Sulfonic Acid, sold under the trade name "EUSOLEX 232" by MERCK;
• Disodium Phenyl Dibenzimidazole Tetra-sulfonate, sold under the trade name "NEO HELIOPAN AP" by HAARMANN and REIMER;

• Drometrizole Trisiloxane, sold under the trade name "Silatrizole" by RHODIA CHIMIE;
• Methylene bis-Benzotriazolyl Tetramethylbutylphenol, sold in the solid form under the trade name "MIXXIM BB/100" by FAIRMOUNT CHEMICAL or in the micronized form in aqueous dispersion under the trade name "TINOSORB M" by CIBA SPECIALTY CHEMICALS;

• Menthyl anthranilate, sold under the trade name "NEO HELIOPAN MA" by HAARMANN and REIMER;

• Ethylhexyl Dimethoxybenzylidene Dioxoimidazoline Propionate;

• Di-neopentyl 4'-methoxybenzalmalonate;
• Polyorganosiloxane with benzalmalonate functions, such as Polysilicone-15, sold under the trade name
• "PARSOL SLX" by HOFFMANN LA ROCHE;

• 1,1-dicarboxy (2,2'-dimethylpropyl)-4,4-diphenylbutadiene;

• 2,4-bis-[5-1(dimethylpropyl)benzoxazol-2-yl-(4-phenyl)-imino]-6-(2-ethylhexyl)-imino-1,3,5-triazine, sold under the trade name "Uvasorb K2A" by Sigma 3V; and mixtures thereof.

Preferred complementary organic photoprotective agents are selected from:

• Ethylhexyl Methoxycinnamate;
• Homosalate;
• Ethylhexyl Salicylate;
• Butyl Methoxydibenzoylmethane;
• Octocrylene;
• Phenylbenzimidazole Sulfonic Acid;
• Benzophenone-3;
• Benzophenone-4;
• Benzophenone-5;
• n-hexyl 2-(4-diethylamino-2-hydroxybenzoyl)-benzoate;
• 4-methylbenzylidene camphor;
• Terephthalylidene Dicamphor Sulfonic Acid;
• Disodium Phenyl Dibenzimidazole Tetra-sulfonate;
• Methylene bis-Benzotriazolyl Tetramethylbutyl-phenol;
• Drometrizole Trisiloxane;
• Polysilicone-15;
• Di-neopentyl 4'-methoxybenzalmalonate;
• 1,1-dicarboxy (2,2'-dimethylpropyl)-4,4-diphenyl-butadiene;

Inorganic photoprotective agents are selected from pigments or nanopigments (mean primary particle size: generally between 5 nm and 100 nm, preferably between 10 nm and 50 nm) of metallic oxides which may or may not be coated, for example titanium oxide nanopigments (amorphous or crystalline in the rutile and/or anatase form), iron, zinc, zirconium or cerium, and mixtures thereof. Conventional coating agents include alumina and/or aluminium stearate. Such metallic oxide nanopigments, which may or may not be coated, are in particular described in European patent applications EP-A-0 518 772 and EP-A-0 518 773.

The additional photoprotective agents are generally present in the compositions according to the invention in proportions of 0.01% to 20% by weight with respect to the total composition weight, preferably 0.1% to 10% by weight with respect to the total composition weight.

The compositions of the invention may be in any of the forms which are suitable for topical application, in particular in the form of aqueous gels, in the form of emulsions obtained by dispersion of a fat phase (also termed the oily phase) in an aqueous phase (O/W) or the reverse (W/H), or multiple emulsions (for example W/O/W or O/W/O or O/O/W). They may be more or less fluid and have the appearance of a white or coloured cream, a pomade, a milk, a lotion, a serum, a paste, a powder, a solid stick, and may optionally be packaged as an aerosol and in the form of a foam or spray. These compositions are prepared using the usual methods.

In a particular implementation of the invention, the composition of the invention is in the form of an emulsion and then comprises at least one oily phase. The proportion of the oily phase of the emulsion may be from 1% to 80% by weight, preferably 2% to 50% by weight and more preferably 2% to 40% by weight with respect to the total composition weight. The fats in the oily phase, in particular oils, and the emulsifying and co-emulsifying agents which may be present, used in the composition in the form of an emulsion are selected from those conventionally used in the cosmetics or dermatological field. The emulsifying and co-emulsifying agent, when present, are generally present in a proportion of 0.1% to 30% by weight, preferably 0.3% to 20% by weight and more preferably 0.5% to 15% by weight with respect to the total composition weight. The emulsion may also contain lipid vesicles in addition to or in place of the emulsifying and/or co-emulsifying agents.

The emulsions generally contain at least one emulsifying agent selected from amphoteric, anionic, cationic or nonionic emulsifying agents used alone or as a mixture. The emulsifying agents are suitably selected as a function of the continuous phase of the emulsion to be produced (W/H or O/W). When the emulsion is a multiple emulsion, it generally comprises an emulsifying agent in the primary emulsion and an emulsifying agent in the external phase into which the primary emulsion is introduced.

Emulsifying agents which may be used to prepare W/H emulsions which may be cited, are for example alkyl esters or sorbitan ethers, glycerol or sugars; silicone surfactants such as dimethicone copolyols, such as the mixture of cyclomethicone and dimethicone copolyol, sold under the trade names DC 5225 C and DC 3225 C by Dow Corning and such as alkyl-dimethicone copolyols such as Laurylmethicone copolyol sold under the trade name "Dow Corning 5200 Formulation Aid" by Dow Corning, Cetyl dimethicone copolyol sold under the trade name Abil EM 90^R by Goldschmidt and the mixture of Polyglyceryl-4 isostearate/Cetyl dimethicone copolyol/Hexyl laurate sold under the trade name Abil WE 09^R by Goldschmidt. It is also possible to add thereto one or more co-emulsifying agents which, advantageously, may be selected from the group comprising esters of fatty acids with a branched chain and polyol, in particular esters of fatty acid with a branched chain and glycerol and/or sorbitan and, for example, polyglyceryl isostearate, such as the product sold under the trade name Isolan GI 34 by Goldschmidt, sorbitan isostearate, such as the product sold under the trade name Arlacel 987 by ICI, sorbitan isostearate and glycerol, such as the product sold under the trade name Arlacel 986 by ICI, and mixtures thereof.

Examples of emulsifying agents suitable for the preparation of O/W emulsions which may be cited are nonionic emulsifying agents such as esters of fatty acids and oxyalkylenated polyols (more particularly polyoxyethylenated), for example polyethylene glycol stearates such as PEG-100 stearate, PEG-50 stearate and PEG-40 stearate; esters of fatty acids and oxyalkylenated sorbitan comprising 20 to 100 OE, for example, and for example those sold under the trade name Tween 20 or Tween 60 by Uniqema; ethers of oxyalkylenated (oxyethylenated and/or oxypropylenated) fatty alcohols; esters of sugars, alkoxylated or not, such as sucrose stearate and such as PEG-20 methylglucose sesquistearate; sorbitan esters such as sorbitan palmitate sold under the trade name Span 40 by Uniqema; esters of a dibasic acid and a fatty alcohol, such as dimyristyl tartrate; mixtures of these emulsifying agents such as a mixture of glyceryl stearate and PEG-100 stearate (CTFA name: Glyceryl Stearate/PEG-100 Stearate) sold under the trade name Arlacel 165 by Uniqema and under the trade name SIMULSOL 165 by SEPPIC; or the mixture of dimyristyl tartrate, cetearyl alcohol, Pareth-7 and PEG-25 laureth-25, sold under the trade name Cosmacol PSE by Sasol (CTFA name: Dimyristyl tartrate/cetearyl alcohol/12-15 Pareth 7/PPG 25 laureth 25).

Co-emulsifying agents may be added to said emulsifying agents, such as fatty alcohols containing 8 to 26 carbon atoms, such as cetyl alcohol, stearyl alcohol and a mixture thereof (cetearyl alcohol), octyldodecanol, 2-butyloctanol, 2-hexyldecanol, 2-undecylpentadecanol or oleic alcohol, or fatty acids, for example.

It is also possible to prepare emulsions without emulsifying surfactants or containing less than 0.5% of the total composition weight, using suitable compounds which can stabilize said emulsions, for example amphiphilic polymers, electrolytes.

When the composition of the invention is in the form of an emulsion, it comprises at least one oily phase which contains at least one oil, in particular a cosmetic oil. The term "oil" means a fat which is liquid at ambient temperature (25°C).

Examples of oils which can be used in the composition of the invention are hydrocarbon-containing oils of animal origin such as perhydrosqualene (or squalane); hydrocarbon-containing oils of vegetable origin, such as caprylic/capric acid triglycerides such as those sold by Stearineries Dubois or those sold under the trade name Miglyol 810, 812 and 818 by Dynamit Nobel, or oils of vegetable origin, for example sunflower, corn, soya, gourd, grapeseed, sesame, hazelnut, apricot, macadamia nut, arara, coriander, castor, avocado, jojoba oil, shea butter oil; synthesized oils; silicone oils such as volatile or non-volatile polymethylsiloxanes (PDMS) with a linear or cyclic silicone chain, which are liquid or pasty at ambient temperature; fluorinated oils such as partially hydrocarbonated and/or silicone oils, such as those described in Japanese document JP-A-2-295912; ethers such as dicapryl ether (CTFA name: Dicaprylyl ether); and benzoates of C₁₂-C₁₅ fatty alcohols (Finsolv TN from FINETEX); arylalkyl benzoate derivatives such as 2-phenylethyl benzoate (X-Tend 226 from ISP); amide oils such as isopropyl N-lauroylsarcosinate (ELDEW SL-205 from Ajimoto) and mixtures thereof.

The oily phase may also comprise one or more fats selected, for example, from fatty alcohols (cetyl alcohol, stearyl alcohol, cetearyl alcohol), fatty acids (stearic acid) and waxes (paraffin, polyethylene waxes, carnauba, beeswax).

The composition of the invention may also contain one or more organic solvents which may be selected from the group constituted by hydrophilic organic solvents, lipophilic organic solvents, amphiphilic solvents or mixtures thereof.

Examples of hydrophilic organic solvents which may be cited, for example, are linear or branched monohydric alcohols containing 1 to 8 carbon atoms, such as ethanol, propanol, butanol, isopropanol or isobutanol; polyethylene glycols containing 6 to 80 ethylene oxides; polyols such as propylene glycol, isoprene glycol, butylene glycol, glycerol or sorbitol; mono- or di-alkyl isosorbides the alkyl groups of which contain 1 to 5 carbon atoms, such as dimethyl isosorbide; glycol ethers such as diethylene glycol mono-methyl or mono-ethyl ether and propylene glycol ethers such as dipropylene glycol methyl ether.

Amphiphilic organic solvents which may be cited include polypropylene glycol (PPG) derivatives, such as esters of polypropylene glycol and fatty acids, PPG and fatty alcohol such as PPG-23 oleyl ether and PPG-36 oleate.

Examples of lipophilic organic solvents which may be cited are fatty esters such as diisopropyl adipate, dioctyl adipate or alkyl benzoates.

The compositions of the present invention may also comprise conventional cosmetic adjuvants selected from softeners, moisturizers, opacifying agents, stabilizers, emollients, silicones, anti-foaming agents, fragrances, preservatives, anionic, cationic, nonionic, zwitterionic or amphoteric surfactants, fillers, polymers, propellants, alkalinizing or acidifying agents or any other ingredient which is normally used in the cosmetics and/or dermatological field.

Hydrophilic thickeners which may be cited include carboxyvinyl polymers such as carbopols (carbomers) and Pemulens (Copolymer acrylate/C10-C30-alkylacrylate); cellulose derivatives such as hydroxyethylcellulose; polysaccharides and in particular, gums such as xanthan gum; and mixtures thereof.

Lipophilic thickeners which may be cited include modified clays, such as hectorite and its derivatives, for example products sold under the trade name Bentone.

Preservatives which may be cited include parahydroxybenzoic acid esters also known as Parabens® (in particular methyl paraben, ethyl paraben, propyl paraben), phenoxyethanol, formol liberators such as, for example, imidazolidinyl urea or diazolidinyl urea, chlorhexidine digluconate, sodium benzoate, caprylyl glycol, iodopropynyl butyl carbamate, pentylene glycol, alkyl trimethylammonium bromide such as myristyltrimethylammonium bromide (CTFA name: Myrtrimonium bromide), dodecyl-trimethylammonium bromide, hexadecyltrimethylammonium bromide, and mixtures thereof such as the mixture sold under the trade name Cetrimide® by FEF CHEMICALS. The preservative may be present in the composition of the invention in an amount of 0.001% to 10% by weight with respect to the total composition weight, especially 0.1% to 5% by weight, and in particular 0.2% to 3% by weight.

Examples of fillers which may be used in the composition of the invention which may be cited are, for example, pigments; silica powder; talc; polyamide particles, in particular those sold under the trade name ORGASOL by Atochem; polyethylene powders; powders of natural organic materials such as starch powders, in particular of corn, wheat or rice starch, which may or may not be cross-linked, such as powders of starch cross-linked by octenylsuccinate anhydride, sold under the trade name DRY-FLO by National Starch; microspheres based on acrylic copolymers, such as those formed from an ethylene glycol dimethacrylate/lauryl methacrylate copolymer sold by Dow Corning under the trade name POLYTRAP; polymethylmethacrylate powders such as those sold under the trade name MICROPEARL M 100 by Matsumoto; expanded powders such as hollow microspheres, in particular microspheres sold under the trade name EXPANCEL by Kemanord Plast or under the trade name MICROPEARL F 80 ED by Matsumoto; silicone resin microbeads, such as those sold under the trade name TOSPEARL by Toshiba Silicone; polyurethane powders, such as hexamethylene diisocyanate/trimethylol hexyllactone copolymer sold under the trade name Plastic Powder D-400 by Toshiba Pigment (CTFA name: HDI/Trimethylol Hexyllactone Crosspolymer); and mixtures thereof. When they are present, these fillers may be in quantities of 0.001% to 20% by weight, preferably 0.1% to 10% by weight and more preferably 1% to 5% by weight with respect to the total composition weight.

Clearly, the skilled person will take care to select any complementary compounds as cited above and/or their quantities such that the advantageous properties intrinsically attached to the combination in accordance with the invention are not impaired or not substantially impaired by the envisaged adjuncts.

The composition of the invention may constitute a skin care product, in particular for the face, the neck, the contours of the eye, the body; or a skin makeup product such as a tinting product (in particular a foundation), an eye shadow, a blusher, an eye-liner, a concealer, a body makeup product, a sun protection product or a skin cleansing product. Preferably, the composition of the invention is a sun protection product.

The composition is generally not washed off, but may be washed off if it constitutes a cleansing product, in particular a foaming product.

The invention also provides a method for the cosmetic treatment of a keratinous material such as the skin, eyelashes, eyebrows, nails or mucosal membranes, characterized in that a composition as defined above is applied to the keratinous material.

The compositions of the invention may be in the form of sprayable fluid lotions in accordance with the invention which are applied to the skin or the hair in the form of fine particles using pressurization devices. The devices of the invention are well known to the skilled person and include non-aerosol pumps or atomizers, aerosol receptacles comprising a propellant and aerosol pumps using compressed air as the propellant. These latter have been described in US-A-4 077 441 and US-A-4 850 517 (forming an integral part of the contents of the description).

Compositions packaged in aerosol form in accordance with the invention generally contain conventional propellants such as hydrofluorinated compounds, dichlorodifluoromethane, difluoroethane, dimethylether, isobutane, n-butane, propane or trichlorofluoromethane. They are preferably present in quantities of 15% to 50% by weight with respect to the total composition weight.

The invention will now be described with reference to the following examples, given by way of non-limiting illustration. In the examples, unless otherwise indicated, the quantities are expressed as percentages by weight.

1-amino-[1,3,3,3-tetramethyl-1-[(trimethylsilyl) - oxy]disiloxanyl]-3-propane (41.7 g, 0.149 mol) and a solution of sodium bicarbonate (11.4 g, 0.135 mol) in 120 ml of water were added dropwise at 0°C to a solution of cyanuryl chloride (25 g, 0.135 mol) in 250 ml of acetone so that the pH was between 3 and 6.5. Following introduction, the pH was 6.5. Stirring was then maintained for 1 hour 30 minutes at 10°C, then left at laboratory temperature. The precipitate formed was filtered, washed with water, drained and dried. 55.2 g (yield: 95%) of the expected derivative were obtained in the form of a white powder (MP: 59°C).

A mixture of the above product (2.1 g, 0.005 mol) and ethyl para-aminobenzoate (1.65 g, 0.01 mol) in suspension in 20 ml of toluene was heated under reflux for 1 hour 30 minutes. It was cooled and hot heptane was added to the resin obtained. After grinding, filtering and drying, 2.3 g (yield: 67%) of the derivative of Example 1 were obtained in the form of a white powder:

• MP: 106-108°C
• UV (ethanol): λ_max = 311 nm; E1% = 1147.

A mixture of the product from the first step of Example 1 (16.74 g, 0.0391 mol), butyl para-aminobenzoate (15 g, 0.0776 mol) and potassium carbonate (5.36 g, 0.0388 mol) was taken up in suspension in 170 ml of toluene with nitrogen bubbling through and heated under reflux for 1 hour 20 minutes. The reaction mixture was cooled and 150 ml of dichloromethane were added. The minerals were filtered. The filtrate was washed with bicarbonated water then twice with water. After drying the organic phase and evaporating off the solvents, a white powder was obtained. After recrystallization from a 1:15 EtOAc/heptane mixture, 20.1 g (yield: 69%) of the derivative of Example 2 were obtained in the form of a white powder:

• MP: 110-111°C
• UV (ethanol): λ_max = 310 nm; E1% = 1020.

A mixture of the product from the first step of Example 1 (1 g, 2.3 x 10^-3 mol), n-pentyl para-aminobenzoate (0.97 g, 4.6 x 10^-3 mol) and sodium bicarbonate (0.39 g, 4.6 x 10^-3 mol) in 15 ml of toluene was heated for 20 minutes to a temperature of 115°C in a CEM Discover microwave oven at a power of 150 watts. Dichloromethane was added to the reaction mixture and it was washed with a saturated solution of sodium chloride then twice with water. After drying the organic phase and evaporating off the solvents, a transparent oil was obtained. After purifying on a silica column (eluent: heptane/EtOAc 85:15), the fractions of the derivative of Example 3 (0.9 g; yield: 50%) were recovered in the form of a white powder:

• UV (ethanol): λ_max = 312 nm; E1% = 1008.

Tert-octylamine (51.7 g, 0.4 mol) and triethylamine (61.2 ml, 0.44 mol) in 260 ml of dichloromethane were introduced into a reactor. It was heated to 70°C then 4-nitrobenzoyl chloride (77.9 g, 0.42 mol) was added in small portions over 50 minutes. It was heated under reflux for 4 hours. The reaction mixture was poured over ice water; it was extracted with dichloromethane, dried and the solvent was evaporated off. The beige precipitate obtained was recrystallized from a mixture of isopropyl ether and ethanol (ratio 10:1). After drying under vacuum, 84.6 g (yield: 76%) of 4-nitro-N-(tert-octyl)benzamide were obtained in the form of an off-white powder and used as is in the next step.

4-nitro-N-(tert-octyl)benzamide (30 g, 0.108 mol) dissolved in 200 ml of ethyl acetate was hydrogenated in a 500 ml hydrogenator in the presence of 4.8 g of palladium, 10% on charcoal with 50% water as the catalyst (hydrogen pressure: 8-10 bar) at a temperature of 70-75°C for 1 hour and 15 minutes. After filtering, concentrating the solvent and vacuum drying, 20.4 g (yield: 76%) of 4-amino-N-(tert-octyl)benzamide were obtained in the form of a pale yellow powder and used as is in the next step.

A mixture of the product from the first step of Example 1 (1 g, 2.3 x 10^-3 mol), the product from the preceding step (1.16 g, 4.6 x 10^-3 mol) and sodium bicarbonate (0.39 g, 4.6 x 10^-3 mol) in 10 ml of dry toluene was heated in a CEM Discover microwave oven for 20 minutes to a temperature of 115°C at a power of 150 watts. Dichloromethane was added to the reaction mixture and it was washed with a saturated solution of sodium chloride then twice with water. After drying the organic phase and evaporating off the solvents, a pale yellow oil was obtained. After purifying on a silica column (eluent: heptane/EtOAc 70:30), the fractions of the derivative of Example 3 were recovered (0.9 g; yield: 45%) in the form of white flakes:

• UV (ethanol): λ_max = 302 nm; E1% = 775.

Chloromethyltrimethylsilyl (38.5 g, 0.314 mol) was added dropwise at 80°C to a heterogeneous mixture of the potassium salt of para-aminobenzoic acid (50 g. 0.285 mol) in 350 ml of DMF in a reactor. It was heated under reflux for 3 hours. After cooling, the salts were filtered and the DMF was evaporated off. The residue was taken up in dichloromethane, dried and the solvent was evaporated off. The oil obtained was purified by distillation. Fractions were recovered which distilled at 189°C in a vacuum of 0.6 mbar. The oil crystallized out. 50.4 g (yield: 79%) of the derivative of Example 5 were obtained in the form of a white powder and used as is in the next step.

A mixture of the product from the first step of Example 1 (2.1 g, 4.9 x 10^-3 mol) and the derivative from the preceding step (2.19 g, 9.8 x 10^-3 mol) in 40 ml, of toluene was heated under reflux for 5 hours with nitrogen bubbling through. It was cooled and the solvent was evaporated off. The residue was taken up in dichloromethane, dried and the solvent was evaporated off. 3 g (yield: 76%) of the derivative of Example 5 were obtained in the form of a pale yellow gum:

• UV (ethanol): λ_max = 311 nm; E1% = 907.

A mixture of 2-ethylhexyl 2-hydroxy-4-aminobenzoate (1.4 g, 5.57 x 10^-3 mol) and the product from the first step of Example 1 (1.19 g, 2.78 x 10^-3 mol) in 10 ml of toluene was heated under reflux for 5 hours with nitrogen bubbling through. It was cooled and the solvent was evaporated off. The residue was chromatographed on a silica column (eluent: heptane/EtOAC 9:1). 1.58 g (yield: 64%) of the fractions of the derivative of Example 6 were obtained in the form of a white paste:

n-Butyl para-aminobenzoate (113.94 g, 0.59 mol) and a potassium carbonate solution (40.68 g, 0.295 mol) in 50 ml of water were simultaneously added dropwise at 5°C to a solution of cyanuryl chloride (54.36 g, 0.295 mol) in 500 ml of dioxane and 50 ml of water so that the pH was between 3 and 6.5. It was kept at 5°C for 1 hour 30 minutes. A precipitate formed in the medium which corresponded to the monosubstituted s-triazine. It was heated steadily to 70°C and the second equivalent of potassium carbonate (40.68 g, 0.295 mol) was added in 50 ml of water. Stirring was then maintained for 5 hours at 70°C. The reaction mixture was cooled and filtered. The precipitate formed was washed with water, drained and dried. After recrystallizing from dioxane/water, after vacuum drying, 52.5 g (yield: 36%) of 2,4-bis(n-butyl-4'-diylaminobenzoate)-6-chloro-s-triazine were obtained from the first recrystallization in the form of a white powder after vacuum drying.

A mixture of the preceding product (2 g, 4 x 10^-3 mol), aminopropyl terminated polydimethylsiloxane (DMS-A-11 from Gelest) (2.13 g, 2 x 10^-3 mol) and pyridine (0.32 ml, 4 x 10^-3 mol) in 40 ml of toluene was heated to 70°C for 5 hours with nitrogen bubbling. It was cooled, dichloromethane was added and the organic phase was washed 3 times with water. After drying the organic phase and evaporating off the solvents, a brown oil was obtained. After treatment with carbon black in hot ethanol and filtering over Celite, 3.3 g (yield: 70%) of the derivative of Example 7 were obtained in the form of a light brown gum:

• UV (ethanol): λ_max = 311 nm; E1% = 916.

A heterogeneous mixture of the product from the first step of Example 7 (20 g, 0.04 mol) and aminopropyl diethoxymethylsilane (15.37 g, 0.08 mol) was heated steadily to 70°C with nitrogen bubbling through. After one hour, it was cooled, dichloromethane was added and the organic phase was washed 3 times with water. After drying the organic phase and evaporating off the solvents then recrystallizing from heptane, 21 g (yield: 80%) of a white solid of the derivative of Example 8 were obtained:

A heterogeneous mixture of the product of Example 8 (1 g, 1.53 x 10^-3 mol), decamethylcyclopentasiloxane (D5) (0.57 g, 1.53 x 10^-3 mol), hexamethyldisiloxane (MM) (0.062 g, 0.38 x 10^-3 ml) and concentrated hydrochloric acid (0.1 ml) was vigorously stirred with nitrogen bubbling through in a mixture of 10 ml of toluene and 1 ml of water. It was heated steadily to 70°C and left at this temperature for 2 hours. After cooling to ambient temperature and diluting with water, the whole medium was filtered. The precipitate obtained was washed with water and dried. 0.56 g of a white powder of the derivative of Example 9 was obtained:

• UV (ethanol): λ_max = 311 nm; E1% = 892.

The following oil/water emulsions were produced; the quantities are expressed as percentages by weight with respect to the total weight of each composition.

The aqueous phase (phase B) containing all of its ingredients was heated to 80°C on a water bath. The fatty phase (phase A) containing all of its ingredients was heated to 80°C on a water bath. A was emulsified into B using a rotor-stator agitator (a device sold by Moritz). Phase C was incorporated and it was allowed to return to ambient temperature with moderate stirring. Triethanolamine was introduced to adjust the pH to the desired value at the end of fabrication.

For each formula, 3 test samples and 3 reference samples were prepared. 2 mg/cm² of formula were deposited onto polymethylmethacrylate plates using a spatula.

The test plates were exposed for 37 min in a SUN TEST HERAUS provided with a Xenon lamp having a UV-A flux of 9.68.10^-3 W/cm² and a UV-B flux of 5.76.10^-4 W/cm² .

The reference plates were kept for the same period at the same temperature (38-40°C) in darkness.

At the end of this period, the filters were extracted by immersing each plate in 50 g of methanol and subjecting them to ultrasound for 15 minutes to ensure proper extraction. The solutions obtained were analysed by HPLC and UV spectrophotometry.

For each test formula, the amount of residual 4-tertiobutyl-4'-methoxy-dibenzoylmethane after exposure was given by the ratio of its optical density (OD) in the exposed sample to its unexposed optical density (OD). The absorption maximum corresponding to butyl-methoxy-dibenzoylmethane was used: λ_max = 358 nm.

The results obtained are summarized in the following table:

Formulations 1 and 2, in accordance with the invention, containing 4-tertiobutyl-4'-methoxydibenzoylmethane combined with a compound with formula (1) (i.e. 2,4-bis(n-butyl 4'-diylaminobenzoate)-6-{[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]disiloxanyl}propyl-3-ylamino}-s-triazine) were substantially more photostable than formulation 3 containing 4-tertiobutyl-4'-methoxy-dibenzoylmethane alone.