WO2012119860A1 - Cosmetic composition containing a dibenzoylmethane derivative and a monoester-monoamide compound of methylsuccinic acid; process for photostabilizing a dibenzoylmethane derivative - Google Patents

Abstract

The present invention relates to a cosmetic composition containing the combination of at least one screening agent of the dibenzoylmethane derivative type and of at least one monoester-monoamide compound of methylsuccinic acid of formula (I) below or an optical or geometric isomer thereof: The invention also relates to a process for radiation-photostabilizing at least one screening agent of the dibenzoylmethane derivative type with a monoester-monoamide compound of methylsuccinic acid of formula (I) as defined above.

Description

COSMETIC COMPOSITION CONTAINING A DIBENZOYLMETHANE DERIVATIVE AND A MONOESTER-MONOAMIDE COMPOUND OF METHYLSUCCINIC ACID; PROCESS FOR PHOTOSTABILIZING A DIBENZOYLMETHANE DERIVATIVE

The present invention relates to a cosmetic composition containing the combination of at least one screening agent of the dibenzoylmethane derivative type and of at least one monoester-monoamide compound of methylsuccinic acid.

The invention also relates to a process for radiation-photostabilizing at least one screening agent of the dibenzoylmethane derivative type with a monoester- monoamide compound of methylsuccinic acid of formula (I), the definition of which will be given hereinbelow.

The present invention also relates to the use of at least one monoester- monoamide compound of methylsuccinic acid of formula (I) in a composition comprising, in a cosmetically acceptable support, at least one dibenzoylmethane derivative, for the purpose of improving the efficacy of said composition with respect to UV-A rays.

It is known that light radiation with wavelengths of between 280 nm and 400 nm permits tanning of the human epidermis and that light rays with wavelengths more particularly between 280 nm and 320 nm, known as UV-B rays, cause skin burns and erythema which can harm the development of a natural tan. For these reasons, and also for aesthetic reasons, there is constant demand for means for controlling this natural tanning in order thus to control the colour of the skin; this UV-B radiation should thus be screened out.

It is also known that UV-A rays, with wavelengths between 320 and 400 nm, which cause tanning of the skin, are liable to induce adverse changes therein, in particular in the case of sensitive skin or skin that is continually exposed to solar radiation. UV-A rays cause in particular a loss of elasticity of the skin and the appearance of wrinkles leading to premature ageing of the skin. They promote triggering of the erythemal reaction or amplify this reaction in certain individuals and may even be the cause of phototoxic or photoallergic reactions. Thus, for aesthetic and cosmetic reasons, for instance conservation of the skin's natural elasticity, people increasingly wish to control the effect of UV-A rays on their skin. It is thus desirable also to screen out UV-A radiation.

For the purpose of protecting the skin and keratin materials against UV radiation, antisun compositions comprising organic screening agents that are active in the UV-A region and in the UV-B region are generally used. The majority of these screening agents are liposoluble.

In this respect, one particularly advantageous family of UV-A screening agents is currently constituted of dibenzoylmethane derivatives, and in particular 4-fe/f-butyl- 4'-methoxydibenzoylmethane, which specifically have a high intrinsic absorption power. These dibenzoylmethane derivatives, which are products that are now well known per se as screening agents that are active in the UV-A range, are described in particular in French patent applications FR-A-2 326 405 and FR-A-2 440 933, and also in European patent application EP-A-0 1 14 607; 4-fe/f-butyl-4'- methoxydibenzoylmethane is moreover currently sold under the trade name Parsol 1789® by the company DSM Nutritional Products.

Unfortunately, it has been found that dibenzoylmethane derivatives are products that are relatively sensitive to ultraviolet radiation (especially UV-A radiation), i.e., more specifically, they have an annoying tendency to be degraded more or less rapidly under the action of the latter. Thus, this substantial lack of photochemical stability of dibenzoylmethane derivatives towards ultraviolet radiation, to which they are by nature intended to be subjected, does not make it possible to guarantee constant protection during prolonged exposure to the sun, so that repeated applications at regular and close intervals of time have to be carried out by the user in order to obtain effective protection of the skin against UV-A rays.

It is known from Patent EP 717 982 that certain amide compounds have a photostabilizing effect on dibenzoylmethane derivatives and more particularly amide-containing oils, such as the compound N,N-diethyl-3-methylbenzamide with the structure:

or ethyl N-butyl-N-acetyl

However, for effective stabilization, 20% to 30% of the latter compound are needed. This compound has substantial solvent power for all the starting materials used for preparing the formulations, which has the consequence of being reflected by destabilization of the compositions, making the compositions containing such a combination unsuitable for use. Photostabilization of dibenzoylmethane derivatives towards UV-radiation with non- screening compounds thus constitutes, at the present time, a problem that has still not been solved entirely satisfactorily.

The Applicant has now discovered, surprisingly, that by combining the dibenzoylmethane derivatives mentioned above with an effective amount of a monoester-monoamide compound of methylsuccinic acid of formula (I) that will be defined in detail below, it is possible to substantially and appreciably further improve the photochemical stability (or photostability) of these same dibenzoylmethane derivatives and their efficacy in the UV-A range. Compositions containing such a combination also result, after application, in a more uniform distribution of the UV-Screening agent. The compounds of formula (I) also have the advantage of being able to be incorporated in the formulations without destabilizing them.

These discoveries form the basis of the present invention.

Thus, in accordance with one of the subjects of the present invention, a composition is now proposed comprising, in a cosmetically acceptable support, at least one UV-screening system, characterized in that it comprises:

(a) at least one UV-A screening agent of dibenzoylmethane derivative type and (b) at least one monoester-monoamide compound of methylsuccinic acid of formula (I), the definitions of which will be given hereinbelow.

Another subject of the invention also concerns a process for improving the chemical stability towards UV radiation of at least one UV-A screening agent of dibenzoylmethane derivative type that consists in combining with said dibenzoylmethane derivative at least one monoester-monoamide compound of methylsuccinic acid of formula (I), the definitions of which will be given hereinbelow. Finally, another subject of the present invention is the use of a monoester- monoamide compound of methylsuccinic acid of formula (I) in a composition comprising, in a cosmetically acceptable support, at least one dibenzoylmethane derivative, for the purpose of improving the efficacy of said composition with respect to UV-A rays.

Other features, aspects and advantages of the invention will emerge on reading the detailed description that follows.

The term "cosmetically acceptable" means compatible with the skin and/or its integuments, having a pleasant colour, odour and feel and not causing any unacceptable discomfort (stinging, tautness or redness) liable to discourage the consumer from using this composition.

Among the dibenzoylmethane derivatives that may especially be mentioned, in a non-limiting manner, are:

- 2-methyldibenzoylmethane,

- 4-methyldibenzoylmethane,

- 4-isopropyldibenzoylmethane,

- 4-fe/f-butyldibenzoylmethane,

- 2,4-dimethyldibenzoylmethane,

- 2,5-dimethyldibenzoylmethane,

- 4,4'-diisopropyldibenzoylmethane,

- 4,4'-dimethoxydibenzoylmethane,

- 4-ie f-butyl-4'-methoxydibenzoylmethane,

- 2-methyl-5-isopropyl-4'-methoxydibenzoylmethane,

- 2-methyl-5-ferf-butyl-4'-methoxydibenzoylmethane,

- 2,4-dimethyl-4'-methoxydibenzoylmethane,

- 2,6-dimethyl-4-ie f-butyl-4'-methoxydibenzoylmethane,

- 1 -(4-methoxy-1 -benzofuran-5-yl)-3-phenylpropane-1 ,3-dione (Pongamol). Among the dibenzoylmethane derivatives mentioned above, use will in particular be made of 4-isopropyldib the name Eusolex 8020 by the company Merck, and th ng formula:

It is most particularly preferred to use 4-ie f-butyl-4'-methoxydibenzoylmethane or butyl methoxy dibenzoylmethane or avobenzone, sold under the trade name Parsol 1789 by this screening agent corresponds to th

The dibenzoylmethane derivative(s) may be present in the compositions in accordance with the invention in contents preferably ranging from 0.01 % to 20% by weight and more preferentially from 0.1 % to 10% by weight and more preferentially still from 0.1 % to 6% by weight relative to the total weight of the composition.

The monoester-monoamide derivatives of methylsuccinic acid in accordance with the invent general formula (I) below and

in which:

Ri and R₂, which are identical or different, denote a linear or branched C1-C20 alkyl radical, or a C5-C6 cycloalkyl radical, optionally substituted with one or more identical or different C1-C3 alkyl radicals,

X and Y denote, independently of one another, -O- or -N(R₃)-, with R₃ denoting hydrogen or a linear or branched C1-C20 alkyl radical,

X and Y cannot simultaneously represent O or NR₃;

when X or Y = NR₃, Ri and R₃, or R₂ and R₃, may form, with the nitrogen that bears them, a 5- to 6-membered heterocycle optionally substituted with one or more identical or different Ci-C₃ alkyl radicals.

Preferably, Ri and R₂, which are identical or different, denote a linear or branched C1-C10 alkyl radical, or a C5-C6 cycloalkyl radical, optionally substituted with one or more identical or different Ci-C₃ alkyl radicals, X and Y denote, independently of one another, -0- or -N(R₃)-, with R₃ denoting hydrogen or a linear or branched d-do alkyl radical,

X and Y cannot simultaneously represent 0 or NR₃;

when X or Y = NR₃, Ri and R₃, or R₂ and R₃, may form, with the nitrogen that bears them, a 5- to 6-membered heterocycle.

In the formula (I), mention may in particular be made, among the alkyl groups, of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, fe/f-butyl, n-octyl, 2-ethylhexyl, dodecyl, hexadecyl, cyclohexyl or methylcyclohexyl groups.

In the context of the invention, a monoester-monoamide derivative of methylsuccinic acid of formula (I) is understood to encompass all mesomeric, tautomeric or optical isomeric forms. Among the compounds of formula (I), compounds (a) to (j) below will more preferentially be used:

(i)

The derivatives (c), (d) and (j) will very particularly be preferred.

The derivatives of formula (I) in accordance with the invention are preferably present in the compositions of the invention in contents ranging from 1 % to 30% by weight and more preferentially from 3% to 20% by weight relative to the total weight of the composition.

The derivatives of formula (I), certain syntheses of which are described in the following papers: J. Am. Chem. Soc, 81 , pages 693-6 (1959); Synthetic Communications, 28 (24), pages 4517-24 (1998) and in patent US 4588833 (1983), may be easily obtained from itaconic acid according to the following sche

(IV) m

(VII)

Similarly, it is possible to obtain the compounds of formula (I) for which X according to the following scheme:

Itaconic acid of formula (II), results, after dehydration, in itaconic anhydride of formula (III) which, after catalytic hydrogenation, makes it possible to obtain methylsuccinic anhydride of formula (IV). Methylsuccinic anhydride (IV) is reacted with an amine of formula (V) (respectively an alcohol R2OH), to result in the monoamide-monoacid derivative (VI) (respectively monoester-monoacid derivative (VI)') which is then esterified with an alcohol of formula (V) in the presence of catalyst (respectively amidated with an amine HNR2R3) in order to give the derivative of formula (I).

Methylsuccinic anhydride of formula (IV), (CAS No. 4100-80-5) is readily available commerically, especially from Sigma-Aldrich or PCAS. The compound (j) is novel and constitutes one subject of the invention.

The compositions in accordance with the invention may also comprise other additional organic or inorganic UV-Screening agents which are active in the UV- A and/or UV-B regions that are water-soluble or liposoluble or else insoluble in the cosmetic solvents commonly used.

Needless to say, a person skilled in the art will take care to select the optional additional screening agent(s) and/or the amounts thereof such that the advantageous properties intrinsically associated with the compositions in accordance with the invention are not, or are not substantially, adversely affected by the envisaged addition(s), especially the improvement in the photostability of the dibenzoylmethane derivative.

The additional UV-screening agents are generally present in the compositions according to the invention in proportions ranging from 0.01 % to 20% by weight relative to the total weight of the composition, and preferably ranging from 0.1 % to 10% by weight relative to the total weight of the composition.

The additional organic UV-screening agents are chosen especially from anthranilic derivatives; cinnamic derivatives; salicylic derivatives; benzylidene camphor derivatives; benzophenone derivatives; β,β-diphenylacrylate derivatives; triazine derivatives; phenylbenzotriazole derivatives; benzalmalonate derivatives, especially those cited in patent US 5 624 663; phenylbenzimidazole derivatives; imidazoline derivatives; bis-benzoazolyl 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 1 19; benzoxazole derivatives as described in patent applications EP 0 832 642, EP 1 027 883, EP 1 300 137 and DE 101 62 844; screening polymers and screening silicones, such as those described especially in patent application WO 93/04665; -alkylstyrene-based dimers, such as those described in patent application DE 198 55 649; 4,4-diarylbutadienes, such as those 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 liposoluble or water- soluble merocyanine derivatives.

As examples of organic UV-screening agents, mention may be made of those denoted nereinbelow under their INCI name: para-Am inobenzoic acid derivatives: PABA,

Ethyl PABA,

Ethyl dihydroxypropyl PABA,

Ethylhexyl dimethyl PABA sold in particular under the name Escalol 507 by ISP, Glyceryl PABA,

PEG-25 PABA sold under the name Uvinul P25 by BASF.

Salicylic derivatives:

Homosalate sold under the name Eusolex HMS by Rona/EM Industries,

Ethylhexyl salicylate sold under the name Neo Heliopan OS by Symrise,

Dipropylene glycol salicylate sold under the name Dipsal by Scher,

TEA salicylate sold under the name Neo Heliopan TS by Symrise.

Cinnamic derivatives:

Ethylhexyl methoxycinnamate sold especially under the trade name Parsol MCX by DSM Nutritional Products,

Isopropyl methoxycinnamate,

Isoamyl methoxycinnamate sold under the trade name Neo Heliopan E 1000 by Symrise,

Cinoxate,

DEA methoxycinnamate,

Diisopropyl methylcinnamate,

Glyceryl ethylhexanoate dimethoxycinnamate. β, β-Diphenylacrylate derivatives:

Octocrylene sold especially under the trade name Uvinul N539 by BASF, Etocrylene sold especially under the trade name Uvinul N35 by BASF.

Benzophenone derivatives:

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 1 1 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-(4-diethylamino-2-hydroxybenzoyl)benzoate sold under the trade name Uvinul A+ or in the form of a mixture with octyl methoxycinnamate under the trade name Uvinul A + B by BASF,

1 , 1 '-(1 ,4-Piperazinediyl)bis[1 -[2-[4-(diethylamino)-2-hydroxybenzoyl]phenyl]- methanone (CAS 919803-06-8) in its micronized or non-micronized form.

Benzylidene camphor derivatives:

3- Benzylidene camphor manufactured under the name Mexoryl SD by Chimex,

4- Methylbenzylidene camphor sold under the name Eusolex 6300 by Merck, Benzylidene camphor sulfonic acid manufactured under the name Mexoryl SL by Chimex,

Camphor benzalkonium methosulfate manufactured under the name Mexoryl SO by Chimex,

Terephthalyhdene dicamphor sulfonic acid manufactured under the name Mexoryl SX by Chimex,

Polyacrylamidomethyl benzylidene camphor manufactured under the name Mexoryl SW by Chimex. Phenylbenzimidazole derivatives:

Phenylbenzimidazole sulfonic acid sold in particular under the trade name Eusolex 232 by Merck,

Disodium phenyl dibenzimidazole tetrasulfonate sold under the trade name Neo Heliopan AP by Symrise.

Phenylbenzotriazole derivatives:

Drometrizole trisiloxane sold under the name Silatrizole by Rhodia Chimie, methylene bis-benzotriazolyl tetramethylbutylphenol sold in solid form under the trade name MIXXIM BB/100 by Fairmount Chemical, or in micronized form as an aqueous dispersion under the trade name Tinosorb M by BASF.

Triazine derivatives:

Bis-ethylhexyloxyphenol methoxyphenyl triazine sold under the trade name Tinosorb S by BASF,

Ethylhexyl triazone sold in particular under the trade name Uvinul T150 by BASF,

Diethylhexyl butamido triazone sold under the trade name Uvasorb HEB by Sigma 3V,

2,4,6-Tris(diisobutyl 4'-aminobenzalmalonate)-s-triazine,

2,4,6-Tris(dineopentyl 4'-aminobenzalmalonate)-s-triazine,

2,4-Bis(dineopentyl 4'-aminobenzalmalonate)-6-(n-butyl 4'-aminobenzoate)-s- triazine,

2,4-Bis(n-butyl 4'-aminobenzoate)-6-[(3-{1 ,3,3,3-tetramethyl-1 -[(trimethylsilyl)- oxy]disiloxanyl}propyl)amino]-s-triazine,

the symmetrical triazine screening agents described in patent US 6 225 467, patent application WO 2004/085 412 (see compounds 6 and 9) or the document "Symmetrical Triazine Derivatives" IP.COM Journal, IP.COM INC West Henrietta, NY, US (20 September 2004), especially 2,4,6-tris(biphenyl)-1 ,3,5- triazines (in particular 2,4,6-tris(biphenyl-4-yl-1 ,3,5-triazine) and 2,4,6- tris(terphenyl)-1 ,3,5-triazine which is also mentioned in Beiersdorf patent applications WO 06/035 000, WO 06/034 982, WO 06/034 991 , WO 06/035 007, WO 2006/034 992 and WO 2006/034 985.

Anthranilic derivatives:

Menthyl anthranilate sold under the trade name Neo Heliopan MA by Symrise.

Imidazoline derivatives:

Ethylhexyl dimethoxybenzylidene dioxoimidazoline propionate. Benzalmalonate derivatives: Dineopentyl 4'-methoxybenzalmalonate,

Polyorganosiloxane containing benzalmalonate functions, for instance Polysilicone-15, sold under the trade name Parsol SLX by DSM. 4,4-Diarylbutadiene derivatives:

1 , 1 -Dicarboxy(2,2'-dimethylpropyl)-4,4-diphenylbutadiene.

Benzoxazole derivatives:

2,4-Bis[5-(1 , 1 -dimethylpropyl)benzoxazol-2-yl-(4-phenyl)imino]-6-(2- ethylhexyl)imino-1 ,3,5-triazine, sold under the name of Uvasorb K2A by Sigma 3V,

and mixtures thereof.

Lipophilic merocvanine derivatives:

- Octyl 5-N,N-diethylamino-2-phenylsulfonyl-2,4-pentadienoate,

- the lipophilic merocyanine derivatives of eneral formula (VIII):

(VIII)

in which:

- A is the group -C≡N or -(C=0)OR'₃,

- R'i and R'₂, which are identical or different, represent H, a linear or branched C1-C22 alkyl radical or a C3-C8 cycloalkyl radical that is unsubstituted or substituted with C1-C4 alkyl radicals; - R'i and R'₂ may form, together with the nitrogen, a ring containing the group -(CH₂)m- which may be interrupted by one or more -0-, -S- or by -NH-;

- the radical R'i may form, with the carbon alpha to the nitrogen, a ring containing the group -(CH₂)_m-, which is uninterrupted or interrupted by one or more -0-, -S- or by -NH-;

- R'₃ represents a linear or branched C1-C22 alkyl radical or a C3-C8 cycloalkyl radical that is unsubstituted or substituted with C1-C4 alkyl radicals;

- n is 1 or 2;

- m is an integer ranging from 3 to 7;

with the proviso that:

(i) when n = 2, R'i, R'₂ or R'₃ is an alkyl diradical or else R'i and R'₂ form, together with 2 nitrogen atoms, a cyclic -(CH₂)_m- divalent radical,

(ii) R'i and R'₂ are not simultaneously a hydrogen atom.

The compounds of formula (VIII) may be in the Ε,Ε-, Ε,Ζ- or Ζ,Ζ- geometric isomeric forms. The compounds of formula (VIII) that are particularly preferred are those for which the following conditions are satisfied:

- R'-i , R'₂ denote a linear or branched C1-C3 alkyl or a Cs-Ce cycloalkyl,

- R'₃ denotes a linear or branched d-Cs alkyl,

- n is equal to 1 or 2.

The compounds of formula (VIII) that are more particularly preferred are those of formulae (Ma) to (Mdd) below or their Ε, Ε-, Ε,Ζ- or Ζ,Ζ- isomers:

(Mi) (Mj)

RN=942408-05-1



(Mee) (Mgg)

The merocyanine derivatives of formula (VIII) can be prepared according to a method described in patents US 4 045 229 and US 4 195 999, according to the following scheme (pathway 1 ):

in which the R'i , R'₂ and A radicals have the same meanings as in the formula (VIII).

The derivatives of formula (VIII) can be prepared according to a method described in patent WO 0020388, according to the following scheme (pathway 2):

Pathway 2

(XII I ) m

in which the R'i , R'₂ and A radicals have the same meanings as in the formula (VIII). The derivatives of formula (VIII) in which A represents -(C=0)OR'3 and R'₃ denotes an alkyl having at least 3 carbon atoms may be obtained by transesterification according to the scheme below, which pathway is described in patent US 2008/076940 and which may use, inter alia, as catalyst, titanium(IV) isopropoxide (pathway 3):

The derivatives of formula (VIII) in which R'i and R'₂ denote an alkyl having at least 3 carbon atoms may be obtained by transamination, according to the scheme below (pathway 4):

Pathway 4

in excess

(VI I I )

Hvdrophilic merocyanine derivatives:

The hydrophilic or water-soluble merocyanine compounds in accordance with the invention are chosen from the group formed by: (1 ) those corresponding to one of the formulae (XIV) and (XV) below, and the salts thereof:

in which:

- R"i and R"₂, which are identical or different, represent H; a linear or branched C1-C22 alkyi radical which may contain from 1 to 3 oxygen atoms; a C3-C8 cycloalkyi radical, which is unsubstituted or substituted with C1-C4 alkyi radicals; it being possible for said radicals R"i and R"₂ to contain an alkyi sulphonate radical in its acid or salified form or one or two hydroxyl radicals;

- R"i and R"₂ may form, together with the nitrogen, a ring containing the group -(CH₂)_P-, which is uninterrupted or interrupted by one or more -0-, -S- or by -NH-, - R"i may form, with the carbon alpha to the nitrogen, a ring containing the group -(CH₂)_P-, which is uninterrupted or interrupted by one or more -0-, -S- or by -NH-,

- R"₃ represents a carboxyl, -COOR"₅, -CONHR"₅, -COR"₅, -CONR"₅R"i , S0₂R"₅ or -CN group,

- R"₄ represents a carboxyl, -COOR"₆, -CONHR"₆, -COR"₆, -CONR"₆R"₂ or S0₂R"₆ group,

- R"₅ and R"₆, which are identical or different, represent a linear or branched C-i- C₂₂ alkyi radical which may contain from 1 to 3 oxygen atoms; a C3-C8 cycloalkyi radical, which is unsubstituted or substituted with Ci-C₄ alkyi radicals; it being possible for said radicals R"₅ and R"₆ to contain an alkyi sulphonate radical in its acid or salified form or one or two hydroxyl radicals,

- Z represents the group -(CH₂)r, which is uninterrupted or interrupted by -0-, -S- or by -NRV, and/or is unsubstituted or substituted with one or two C1-C6 alkyi radicals,

- R"₇ is a C1-C5 alkyi radical that may contain an alkyi sulphonate radical in its acid or salified form or one or two hydroxyl radicals,

- o is 1 -2; - p is 1 -7; - 1 is 1 -4;

with at least one or two of the radicals R"i , R"₂, R"₅, R"₆ and R"₇ containing

- either an alkyi sulphonate radical in its acid or salified form,

- or one or two hydroxyl radicals;

with the proviso that:

(i) when o = 2, one of the radicals R"i , R"₅ or R"₆ is an alkyi diradical or R"i and R"₂ together with 2 nitrogen atoms form a cyclic -(CH₂)_P- divalent radical;

(ii) R"i and R"₂ are not simultaneously a hydrogen atom;

(iii) when R"₃ is -CN, then at least one of the radicals R"i , R"₂ or R"₆ must contain an alkyi sulphonate group in its acid or salified form; (2) the merocyanine compounds chosen from the group formed by the following molecules, and also salts thereof and the Ε,Ε-, Ε,Ζ- or Ζ,Ζ- geometric isomeric forms thereof:



20

The term "diradical" means a divalent radical such that the two units

are bonded together by this diradical.

By way of illustration, mention may be made of the compounds (u) and (ar) below:

(ar)

In the case where o = 2, for instance a cyclic -(CH₂)_P- divalent radical formed by R"i and R"₂ with the 2 nitrogen atoms, mention may be made of that of the compound (ax):

(ax)

Examples of linear or branched alkyl radicals that may be mentioned include: methyl, ethyl, n-propyl, isopropyl, 1 -methylethyl, butyl, pentyl, hexyl, 2- ethylhexyl, octyl, 1 -methylheptyl.

As C3-C8 cycloalkyl radicals, mention may be made of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, 1 -methylcyclopropyl, 1 -ethylcyclopropyl, 1 - propylcyclopropyl, 1 -butylcyclopropyl, 1 -methyl-1 -butylcyclopropyl, 1 ,2- dimethylcyclopropyl, 1 -methyl-2-ethylcyclopropyl, cyclooctyl.

The acceptable salts of the merocyanine compounds described in the present invention comprise conventional non-toxic salts of said compounds, such as those formed from organic or mineral bases, such as amine salts, for instance salts of alkanolamines such as triethanolamine, amino acid salts or aminopropanediol salts, and salts of an alkali metal or alkaline-earth metal, for instance sodium or potassium.

The preferred salts are salts of an alkali metal such as sodium or potassium, or salts of an amine such as triethanolamine.

The preferred compounds of formula (XIV) are those for which the following conditions are satisfied:

R"i denotes hydrogen; a linear or branched d-Cs alkyl radical possibly containing from 1 to 3 oxygen atoms,

R"₂ denotes a linear or branched d-Cs alkyl possibly containing from 1 to 3 oxygen atoms or a C5-C6 cycloalkyl,

R"₃ denotes a group -COOR"₅, -CN or -CONHR"₅,

R"₄ denotes a group -COOR"₆, -CONHR"₆ or -S0₂R"₆,

R"₅ denotes a linear or branched Ci-Ci₂ alkyl possibly containing from 1 to 3 oxygen atoms,

o is equal to 1 or 2;

with at least one or two of the radicals R"i, R"₂, R"₅, R"₆ containing - either an alkyl sulphonate radical in its acid or salified form,

- or one or two hydroxyl radicals.

The compounds of formula (XIV) with one or two alkyl sulphonate radicals that are even more particularly preferred are chosen from those having the following formulae:

 he compounds of formula (XIV) containing hydroxyl groups that are particularly

The preferred compounds of formula (XV) are those for which the following conditions are satisfied:

R"i denotes hydrogen; a linear or branched d-do alkyl possibly containing from 1 to 3 oxygen atoms,

R"₂ denotes a linear or branched d-do alkyl possibly containing from 1 to 3 oxygen atoms; a C5-C6 cycloalkyl,

R"₃ denotes a group -COOR"₅ or CN,

R"₄ denotes a group -COOR"₆ or -S0₂R"₆,

R"₅ denotes a linear or branched d-C-12 alkyl possibly containing from 1 to 3 oxygen atoms,

Z is -(CH₂)3- which is unsubstitituted or substituted with two CH₃ groups, o is equal to 1 or 2;

with at least one or two of the radicals R"i , R"₂, R"s, R"6 containing:

- either an alkyl sulphonate radical in its acid or salified form,

- or one or two hydroxyl radicals.

The compounds of formula (XV) that are particularly preferred are those having the following formulae:

(am) (an)

The linear merocyanine derivatives in accordance with the invention, in particular those of formula (XIV), may be prepared according to a method described in patents US 4045229, US 4195999 and US 2009/0170008 according to the following scheme (pathway 1 ):

in which the radicals R"i , R"₂, R"3 and R"₄ have the meaning from formula (XIV).

The cyclic merocyanine derivatives in accordance with the invention, in particular those of formula (XV), may be prepared according to a method described in IP.COM Journal 9(5A), 29-30 (2009) according to the following scheme:

in which the radicals R"i , R"₂, R"3, R"₄ and Z have the meaning from formu (XV).

The preferential additional organic UV-screening agents are chosen from:

ethylhexyl methoxycinnamate,

homosalate,

ethylhexyl salicylate,

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 tetrasulfonate,

ethylhexyl triazone,

bis-ethylhexyloxyphenol methoxyphenyl triazine,

diethylhexyl butamido triazone,

2,4,6-tris(biphenyl-4-yl)-1 ,3,5-triazine,

2,4,6-tris(dineopentyl 4'-aminobenzalmalonate)-s-triazine,

2,4,6-tris(diisobutyl 4'-aminobenzalmalonate)-s-triazine,

2,4-bis(dineopentyl 4'-aminobenzalmalonate)-6-(n-butyl 4'-aminobenzoate)-s triazine,

2,4-bis(n-butyl 4'-aminobenzoate)-6-[(3-{1 ,3,3,3-tetramethyl-1 -[(trimethylsilyl) oxy]disiloxanyl}propyl)amino]-s-triazine,

methylene bis(benzotriazolyl) tetramethylbutylphenol,

drometrizole trisiloxane,

polysilicone-15,

dineopentyl 4'-methoxybenzalmalonate,

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

,4-Bis[5-(1 , 1 -dimethylpropyl)benzoxazol-2-yl-(4-phenyl)imino]-6-(2- ethylhexyl)imino-1 ,3,5-triazine,

and mixtures thereof. The additional inorganic screening agents are chosen from coated or uncoated metal oxide pigments, such as, for example, pigments formed of titanium oxide (amorphous or crystalline in the rutile and/or anatase form), iron oxide, zinc oxide, zirconium oxide or cerium oxide, which are all UV photoprotective agents well known per se.

The pigments may be coated or uncoated. The coated pigments are pigments that have undergone one or more surface treatments of chemical, electronic, mechanochemical and/or mechanical nature with compounds as described, for example, in Cosmetics & Toiletries, February 1990, Vol. 105, pp. 53-64, such as amino acids, beeswax, fatty acids, fatty alcohols, anionic surfactants, lecithins, sodium, potassium, zinc, iron or aluminium salts of fatty acids, metal alkoxides (titanium or aluminium alkoxides), polyethylene, silicones, proteins (collagen, elastin), alkanolamines, silicon oxides, metal oxides or sodium hexametaphosphate.

As is known, silicones are organosilicon polymers or oligomers of linear or cyclic, branched or crosslinked structure, of variable molecular weight, obtained by polymerization and/or polycondensation of suitably functionalized silanes, and are essentially constituted of a repetition of main units in which the silicon atoms are linked together via oxygen atoms (siloxane bond), optionally substituted hydrocarbon-based radicals being directly attached via a carbon atom to said silicon atoms.

The term "silicones" also includes the silanes required for their preparation, in particular alkylsilanes. The silicones used for the coating of the pigments suitable for the present invention are preferably chosen from the group containing alkylsilanes, polydialkylsiloxanes and polyalkylhydrosiloxanes. More preferably still, the silicones are chosen from the group containing octyltrimethylsilane, poly- dimethylsiloxanes and polymethylhydrosiloxanes.

Of course, before being treated with silicones, the metal oxide pigments may have been treated with other surface agents, in particular with cerium oxide, alumina, silica, aluminium compounds or silicon compounds, or mixtures thereof. The coated pigments are more particularly titanium oxides that have been coated:

- with silica, such as the product Sunveil from the company Ikeda and the product Eusolex T-AVO from the company Merck,

- with silica and iron oxide, such as the product Sunveil F from the company Ikeda,

- with silica and alumina, such as the products Microtitanium Dioxide MT 500 SA and Microtitanium Dioxide MT 100 SA from the company Tayca, Tioveil from the company Tioxide and Mirasun TiW 60 from the company Rhodia,

- with alumina, such as the products Tipaque TTO-55 (B) and Tipaque TTO-55 (A) from the company Ishihara and UVT 14/4 from the company Kemira, - with alumina and aluminium stearate, such as the product Microtitanium Dioxide MT 100 TV, MT 100 TX, MT 100 Z and MT-01 from the company Tayca, and the products Solaveil CT-10 W, Solaveil CT 100 and Solaveil CT 200 from the company Uniqema,

- with silica, alumina and alginic acid, such as the product MT-100 AQ from the company Tayca,

- with alumina and aluminium laurate, such as the product Microtitanium Dioxide MT 100 S from the company Tayca,

- with iron oxide and iron stearate, such as the product Microtitanium Dioxide MT 100 F from the company Tayca,

- with zinc oxide and zinc stearate, such as the product BR351 from the company Tayca,

- with silica and alumina and treated with a silicone, such as the products Microtitanium Dioxide MT 600 SAS, Microtitanium Dioxide MT 500 SAS or Microtitanium Dioxide MT 100 SAS from the company Tayca,

- with silica, alumina and aluminium stearate and treated with a silicone, such as the product STT-30-DS from the company Titan Kogyo,

- with silica and treated with a silicone, such as the product UV-Titan X 195 from the company Kemira, or the product SMT-100 WRS from the company Tayca, - with alumina and treated with a silicone, such as the products Tipaque TTO-55 (S) from the company Ishihara or UV Titan M 262 from the company Kemira,

- with triethanolamine, such as the product STT-65-S from the company Titan Kogyo,

- with stearic acid, such as the product Tipaque TTO-55 (C) from the company Ishihara,

- with sodium hexametaphosphate, such as the product Microtitanium Dioxide MT 150 W from the company Tayca.

Other titanium oxide pigments treated with a silicone are preferably T1O2 treated with octyltnmethylsilane, such as the product sold under the trade name T 805 by the company Degussa Silicas, T1O2 treated with a polydimethylsiloxane, such as the product sold under the trade name 70250 Cardre UF TiO2SI3 by the company Cardre, anatase/rutile T1O2 treated with a polydimethylhydrosiloxane, such as the product sold under the trade name Microtitanium Dioxide USP Grade Hydrophobic by the company Color Techniques.

The uncoated titanium oxide pigments are sold, for example, by the company Tayca under the trade names Microtitanium Dioxide MT 500 B or Microtitanium Dioxide MT 600 B, by the company Degussa under the name P 25, by the company Sensient - LCW under the name Transparent titanium oxide PW, by the company Miyoshi Kasei under the name UFTR, by the company Tomen under the name ITS and by the company Tioxide under the name Tioveil AQ.

The uncoated zinc oxide pigments are, for example:

- those sold under the name Z-Cote by the company Sunsmart;

- those sold under the name Nanox by the company Elementis;

- those sold under the name Nanogard WCD 2025 by the company Nanophase Technologies. The coated zinc oxide pigments are, for example: - those sold under the name Z-Cote HP1 by the company Sunsmart (dimethicone-coated ZnO);

- those sold under the name Zinc Oxide CS-5 by the company Toshibi (ZnO coated with polymethylhydrosiloxane);

- those sold under the name Nanogard Zinc Oxide FN by the company Nanophase Technologies (as a 40% dispersion in Finsolv TN, C12-C15 alkyl benzoate);

- those sold under the name Daitopersion ZN-30 and Daitopersion ZN-50 by the company Daito (dispersions in cyclopolymethylsiloxane/oxyethylenated poly- dimethylsiloxane, containing 30% or 50% of nanozinc oxides coated with silica and polymethylhydrosiloxane);

- those sold under the name NFD Ultrafine ZnO by the company Daikin (ZnO coated with perfluoroalkyl phosphate and copolymer based on perfluoroalkyl- ethyl as a dispersion in cyclopentasiloxane);

- those sold under the name SPD-Z1 by the company Shin-Etsu (ZnO coated with silicone-grafted acrylic polymer, dispersed in cyclodimethylsiloxane);

- those sold under the name Escalol Z100 by the company ISP (alumina-treated ZnO dispersed in the ethylhexyl methoxycinnamate/PVP-hexadecene copolymer/methicone mixture);

- those sold under the name Fuji ZnO-SMS-10 by the company Fuji Pigment (ZnO coated with silica and polymethylsilsesquioxane);

- those sold under the name Nanox Gel TN by the company Elementis (ZnO dispersed at a concentration of 55% in C12-C15 alkyl benzoate with hydroxystearic acid polycondensate).

The uncoated cerium oxide pigments are sold, for example, under the name Colloidal Cerium Oxide by the company Rhone-Poulenc.

The uncoated iron oxide pigments are sold, for example, by the company Arnaud under the names Nanogard WCD 2002 (FE 45B), Nanogard Iron FE 45 BL AQ, Nanogard FE 45R AQ and Nanogard WCD 2006 (FE 45R) or by the company Mitsubishi under the name TY-220.

The coated iron oxide pigments are sold, for example, by the company Arnaud under the names Nanogard WCD 2008 (FE 45B FN), Nanogard WCD 2009 (FE 45B 556), Nanogard FE 45 BL 345 and Nanogard FE 45 BL or by the company BASF under the name Transparent Iron Oxide.

As an inorganic screening agent that may be incoporated into the compositions of the invention, mention may also be made of mixtures of metal oxides, especially of titanium dioxide and of cerium dioxide, including the equal-weight mixture of titanium dioxide and of cerium dioxide coated with silica, sold by the company Ikeda under the name Sunveil A, and also the mixture of titanium dioxide and of zinc dioxide coated with alumina, silica and silicone, such as the product M 261 sold by the company Kemira, or the mixture of titanium dioxide and of zinc dioxide coated with alumina, silica and glycerol, such as the product M 21 1 sold by the company Kemira.

The compositions in accordance with the present invention may also comprise standard cosmetic adjuvants chosen especially from fatty substances such as oils, organic solvents, ionic or nonionic, hydrophilic or lipophilic thickeners, softeners, humectants, opacifiers, stabilizers, emollients, silicones, antifoams, fragrances, preserving agents, anionic, cationic, nonionic, zwitterionic or amphoteric emulsifying surfactants, active agents, fillers, polymers, propellants, acidifying or basifying agents or any other ingredient usually used in cosmetics and/or dermatology.

Oils that may be mentioned include mineral oils (liquid paraffin); plant oils (sweet almond oil, macadamia oil, grapeseed oil or jojoba oil); synthetic oils, for instance perhydrosqualene, fatty alcohols, fatty amides (for instance isopropyl lauroyl sarcosinate sold under the name Eldew SL-205 by the company Ajinomoto), fatty acids or fatty esters, for instance the C12-C15 alkyl benzoate sold under the trade name Finsolv TN or Witconol TN by the company Witco, 2- ethylphenyl benzoate, for instance the commercial product sold under the name X-Tend 226® by the company ISP, octyl palmitate, isopropyl lanolate and triglycerides, including capric/caprylic acid triglycerides, dicaprylyl carbonate sold under the name Cetiol CC by the company Cognis, oxyethylenated or oxypropylenated fatty esters and ethers; silicone oils (cyclomethicone and polydimethylsiloxanes, or PDMSs) or fluoro oils, polyalkylenes, and trialkyl trimellitates such as tridecyl trimellitate.

Waxy compounds that may be mentioned include carnauba wax, beeswax, hydrogenated castor oil, polyethylene waxes and polymethylene waxes, for instance the product sold under the name Cirebelle 303 by the company Sasol.

Among the organic solvents that may be mentioned are lower alcohols and polyols. The latter can be chosen from glycols and glycol ethers, such as ethylene glycol, propylene glycol, butylene glycol, dipropylene glycol or diethylene glycol.

Hydrophilic thickeners that may be mentioned include carboxyvinyl polymers, such as Carbopols (Carbomers) and the Pemulens (acrylates/C10-C30 alkyl acrylate copolymer); polyacrylamides, for instance the crosslinked copolymers sold under the names Sepigel 305 (CTFA name: polyacrylamide/C13-14 isoparaffin/Laureth 7) or Simulgel 600 (CTFA name: acrylamide/sodium acryloyldimethyltaurate copolymer/isohexadecane/polysorbate 80) by the company SEPPIC; 2-acrylamido-2-methylpropanesulphonic acid polymers and copolymers, optionally crosslinked and/or neutralized, for instance poly(2- acrylamido-2-methylpropanesulphonic acid) sold by the company Hoechst under the trade name Hostacerin AMPS (CTFA name: ammonium polyacryloyldimethyl taurate or Simulgel 800 sold by the company SEPPIC (CTFA name: sodium polyacryolyldimethyltaurate/polysorbate 80/isohexadecane); copolymers of 2- acrylamido-2-methylpropanesulphonic acid and of hydroxyethyl acrylate, for instance Simulgel NS and Sepinov EMT 10 sold by the company SEPPIC; cellulose derivatives such as hydroxyethyl cellulose; polysaccharides and especially gums such as xanthan gum; water-soluble or water-dispersible silicone derivatives, for instance acrylic silicones, polyether silicones and cationic silicones, and mixtures thereof. Lipophilic thickeners that may be mentioned include synthetic polymers, such as the poly(C10-C30 alkyl acrylates) sold under the names Intelimer IPA 13-1 and Intelimer IPA 13-6 by the company Landec, or else modified clays, such as hectorite and its derivatives, for instance the products sold under the name Bentone.

Of course, a person skilled in the art will take care to select the optional additional compound(s) mentioned above and/or the amounts thereof such that the advantageous properties intrinsically associated with the compositions in accordance with the invention are not, or are not substantially, adversely affected by the envisaged addition(s), especially the improvement in the photostability of the dibenzoylmethane derivative.

The compositions according to the invention may be prepared according to the techniques that are well known to those skilled in the art. They may in particular be in the form of a simple or complex emulsion (O/W, W/O, O/W/O or W/O/W) such as a cream, a milk or a cream-gel; in the form of an aqueous gel; in the form of a lotion. They may optionally be packaged as an aerosol and may be in the form of a foam or a spray.

The compositions according to the invention are preferably in the form of an oil- in-water or water-in-oil emulsion.

The emulsification processes that may be used are of the paddle or impeller, rotor-stator or HHP type.

It is also possible, via HHP (between 50 and 800 bar), to obtain stable dispersions with droplet sizes that may be as low as 100 nm. The emulsions generally contain at least one emulsifying surfactant chosen from amphoteric, anionic, cationic and nonionic emulsifying surfactants, which are used alone or as a mixture. The emulsifiers are appropriately chosen according to the emulsion to be obtained (W/O or O/W). As emulsifying surfactants that may be used for the preparation of the W/O emulsions, examples that may be mentioned include sorbitan, glycerol or sugar alkyl esters or ethers; silicone surfactants, for instance 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 laurylmethicone copolyol sold under the name Dow Corning 5200 Formulation Aid by the company Dow Corning; cetyldimethicone copolyol, such as the product sold under the name Abil EM 90R by the company Goldschmidt, and the mixture of cetyldimethicone copolyol, of polyglyceryl isostearate (4 mol) and of hexyl laurate, sold under the name Abil WE O9 by the company Goldschmidt. One or more coemulsifiers may also be added thereto, which may be chosen advantageously from the group comprising polyol alkyl esters. Polyol alkyl esters that may especially be mentioned include polyethylene glycol esters, for instance PEG-30 dipolyhydroxystearate, such as the product sold under the name Arlacel P135 by the company ICI. Glycerol and/or sorbitan esters that may be mentioned include, for example, polyglyceryl isostearate, such as the product sold under the name Isolan Gl 34 by the company Goldschmidt, sorbitan isostearate, such as the product sold under the name Arlacel 987 by the company ICI, sorbitan glyceryl isostearate, such as the product sold under the name Arlacel 986 by the company ICI, and mixtures thereof.

For the O/W emulsions, examples of emulsifying surfactants that may be mentioned include nonionic emulsifying surfactants such as oxyalkylenated (more particularly polyoxyethylenated) esters of fatty acids and of glycerol; oxyalkylenated esters of fatty acids and of sorbitan; oxyalkylenated (oxyethylenated and/or oxypropylenated) esters of fatty acids, such as the PEG 100 stearate/glyceryl stearate mixture sold, for example, by ICI under the name Arlacel 165; oxyalkylenated (oxyethylenated and/or oxypropylenated) ethers of fatty alcohols; esters of sugars, such as sucrose stearate; or ethers of fatty alcohol and of sugar, in particular alkyl polyglucosides (APGs), such as decyl glucoside and lauryl glucoside, sold, for example, by the company Henkel under the respective names Plantaren 2000 and Plantaren 1200, cetostearyl glucoside, optionally as a mixture with cetostearyl alcohol, sold, for example, under the name Montanov 68 by the company SEPPIC, under the name Tegocare CG90 by the company Goldschmidt and under the name Emulgade KE3302 by the company Henkel, and also arachidyl glucoside, for example in the form of a mixture of arachidyl alcohol, behenyl alcohol and arachidyl glucoside, sold under the name Montanov 202 by the company SEPPIC. According to one particular embodiment of the invention, the mixture of the alkyl polyglucoside as defined above with the corresponding fatty alcohol can be in the form of a self- emulsifying composition, for example as described in document WO-A- 92/06778.

When it is an emulsion, the aqueous phase of this emulsion may comprise a nonionic vesicular dispersion prepared according to known processes (Bangham, Standish and Watkins, J. Mol. Biol. 13, 238 (1965), FR 2 315 991 and FR 2 416 008).

The compositions according to the invention find their application in a large number of treatments, especially cosmetic treatments, of the skin, lips, nails, eyelashes, eyebrows and hair, including the scalp, especially for protecting and/or caring for the skin, lips and/or hair, and/or for making up the skin and/or lips and/or eyelashes and/or eyebrows and/or nails. Another subject of the present invention is constituted of the use of the compositions according to the invention as defined above for the manufacture of products for the cosmetic treatment of the skin, lips, nails, hair, eyelashes, eyebrows and/or scalp, especially care products, sun protection products and makeup products. The cosmetic compositions according to the invention may be used, for example, as makeup products.

The cosmetic compositions according to the invention may be used, for example, as care products and/or sun protection products for the face and/or the body. These compositions according to the invention may be of liquid to semi- liquid consistency, such as milks, relatively smooth creams, cream gels or pastes. They may optionally be packaged as an aerosol and may be in the form of a foam or a spray.

The compositions according to the invention in the form of vaporizable fluid lotions in accordance with the invention are applied to the skin or the hair in the form of fine particles by means of pressurization devices. The devices in accordance with the invention are well known to those skilled in the art and comprise non-aerosol pumps or "atomizers", aerosol containers comprising a propellant and also aerosol pumps using compressed air as propellant. These devices are described in patents US 4 077 441 and US 4 850 517 (which form an integral part of the content of the description). The compositions packaged as an aerosol in accordance with the invention generally contain conventional propellants, such as, for example, hydrofluorinated compounds, dichlorodifluoromethane, difluoroethane, dimethyl ether, isobutane, n-butane, propane or trichlorofluoromethane. They are preferably present in amounts ranging from 15% to 50% by weight relative to the total weight of the composition.

The compositions according to the invention may also comprise additional cosmetic and dermatological active agents. Mention may be made, among active agents, of:

- vitamins (A, C, E, K, PP, etc.) and derivatives or precursors thereof, alone or as mixtures;

- antioxidants;

- free-radical scavengers;

- antiglycation agents;

- calmatives;

- NO-synthase inhibitors;

- agents for stimulating the synthesis of dermal or epidermal macromolecules and/or for preventing their degradation;

- agents for stimulating fibroblast proliferation;

- agents for stimulating keratinocyte proliferation;

- muscle relaxants;

- dermo-relaxing agents,

- tensioning agents;

- keratolytic agents;

- desquamating agents;

- moisturizers, for instance polyols such as glycerol, butylene glycol or propylene glycol;

- antiinflammatory agents;

- agents that act on the energy metabolism of cells; - insect repellents;

- substance P or CGRP antagonists;

- hair-loss counteractants and/or hair restorers;

- anti-wrinkle agents;

- anti-ageing agents;

- astringent agents;

- sebum-regulating agents and anti-seborrhoeic agents.

Of course, a person skilled in the art will take care to select the aforementioned optional additional compound(s) and/or the amounts thereof such that the advantageous properties intrinsically associated with the compositions in accordance with the invention are not, or are not substantially, adversely affected by the envisaged addition(s). A person skilled in the art will select said active agent(s) as a function of the effect desired on the skin, hair, eyelashes, eyebrows or nails.

For caring for and/or making up oily skin, a person skilled in the art will preferably select at least one active agent chosen from desquamating agents, sebum-regulating agents or anti-seborrhoeic agents, and astringents.

OTHER ADDITIONAL INGREDIENTS

To complement and/or optimize the effects imparted by the aforementioned cosmetic and/or dermatological active agents on the keratin materials, it may be advantageous to incorporate into the compositions of the invention other additional ingredients.

In particular, these additional ingredients may impart an immediate visual effect that will be relayed by the biological effect of the aforementioned active agents. They may also, via a mechanical action (e.g.:abrasive fillers), amplify the effect of the aforementioned biological active agents.

Thus, the composition according to the invention may also comprise at least one agent chosen from matting agents, fillers with a soft-focus effect, agents for promoting the naturally pinkish coloration of the skin, abrasive fillers or exfoliants, and mixtures thereof.

Matting agents

The term "matting agent" means agents intended to make the skin visibly more matt and less shiny.

The matting effect of the agent and/or composition containing it may especially be evaluated using a gonioreflectometer, by measuring the ratio R between the specular reflection and the scattered reflection. A value of R of less than or equal to 2 generally indicates a matting effect.

The matting agent may especially be chosen from a rice starch or a corn starch: INCI name: Zea mays (Corn) Starch, kaolinite, talc, a pumpkin seed extract, cellulose microbeads, plant fibres, synthetic fibres, in particular polyamide fibres, expanded acrylic copolymer microspheres, fillers with an optical effect, polyamide powders, silica powders, polytetrafluoroethylene powders, silicone resin powders, acrylic polymer powders, wax powders, polyethylene powders, powders of elastomeric crosslinked organopolysiloxane coated with silicone resin, talc/titanium dioxide/alumina/silica composite powders, compounds that absorb and/or adsorb sebum, and mixtures thereof.

Examples of matting agents that may especially be mentioned include:

- a rice or corn starch, such as the product sold under the trade name Farmal CS 3650 Plus 036500 by National Starch or in particular an aluminium starch octenyl succinate sold under the name Dry Flo® by the company National Starch;

- kaolinite;

- a pumpkin seed extract as sold under the name Curbilene® by the company Indena;

- cellulose microbeads as described in patent application EP 1 562 562;

- natural or synthetic fibres, such as silk fibre, cotton fibre, wool fibre, flax fibre, cellulose fibre extracted especially from wood, from vegetables or from algae, polyamide (Nylon®) fibre, modified cellulose fibre, poly-p- phenyleneterephthamide fibre, acrylic fibre, polyolefin fibre, glass fibre, silica fibre, aramid fibre, carbon fibre, Teflon® fibre, insoluble collagen fibre, polyester fibre, polyvinyl chloride or polyvinylidene chloride fibre, polyvinyl alcohol fibre, polyacrylonitrile fibre, chitosan fibre, polyurethane fibre, polyethylene phthalate fibre, fibres formed from a mixture of polymers, resorbable synthetic fibres, and mixtures thereof described in patent application EP 1 151 742;

- expanded acrylic copolymer microspheres such as those sold by the company Expancel under the name Expancel 551®;

- fillers with an optical effect as described in patent application FR 2 869 796, in particular:

- polyamide (Nylon®) powders, for instance Nylon 12 particles of the Orgasol type from Arkema, with a mean size of 10 microns and a refractive index of 1 .54,

- silica powders, for instance Silica beads SB150 from Miyoshi with a mean size of 5 microns and a refractive index of 1 .45,

- polytetrafluoroethylene powders, for instance PTFE Ceridust 9205F from Clariant, with a mean size of 8 microns and a refractive index of 1 .36,

- silicone resin powders, for instance the silicone resin Tospearl 145A from GE Silicone with a mean size of 4.5 microns and a refractive index of 1 .41 ,

- acrylic polymer powders, especially of polymethyl (meth)acrylate, for instance the PMMA particles Jurymer MBI from Nihon Junyoki, with a mean size of

8 microns and a refractive index of 1 .49, or the Micropearl M100® and F 80 ED® particles from the company Matsumoto Yushi-Seiyaku,

- wax powders, for instance the paraffin wax particles Microease 1 14S from Micropowders, with a mean size of 7 microns and a refractive index of 1 .54, - polyethylene powders, especially comprising at least one ethylene/acrylic acid copolymer, and in particular constituted of ethylene/acrylic acid copolymers, for instance the particles Flobeads EA 209 from Sumitomo (with a mean size of 10 microns and a refractive index of 1 .48),

- elastomeric crosslinked organopolysiloxane powders coated with silicone resin, especially with silsesquioxane resin, as described, for example, in patent US 5 538 793; such elastomer powders are sold under the names KSP-100, KSP-101 , KSP-102, KSP-103, KSP-104 and KSP-105 by the company Shin-Etsu,

- talc/titanium dioxide/alumina/silica composite powders such as those sold under the name Coverleaf® AR-80 by the company Catalyst & Chemicals, and - compounds that absorb and/or adsorb sebum as described in patent application FR 2 869 796. Mention may be made especially of:

- silica powders, for instance the porous silica microspheres sold under the name Silica Beads SB-700 sold by the company Miyoshi, the products Sunsphere® H51 , Sunsphere® H33 and Sunsphere® H53 sold by the company Asahi Glass; the polydimethylsiloxane-coated amorphous silica microspheres sold under the name SA Sunsphere® H- 33 and SA Sunsphere® H-53 sold by the company Asahi Glass;

- powders of amorphous mixed silicates, especially of aluminium and magnesium, for instance the product sold under the name Neusilin UFL2 by the company Sumitomo;

- polyamide (Nylon®) powders, for instance Orgasol® 4000 sold by the company Arkema;

- powders of acrylic polymers, especially of polymethyl methacrylate, for instance Covabead® LH85 sold by the company LCW; of polymethyl methacrylate/ethylene glycol dimethacrylate, for instance Dow Corning

5640 Microsponge® Skin Oil Adsorber sold by the company Dow Corning, or Ganzpearl® GMP-0820 sold by the company Ganz Chemical; of polyallyl methacrylate/ethylene glycol dimethacrylate, for instance Poly-Pore® L200 or Poly-Pore® E200 sold by the company Amcol; of ethylene glycol dimethacrylate/lauryl methacrylate copolymer, for instance Polytrap® 6603 sold by the company Dow Corning;

- silicate particles, such as alumina silicate;

- mixed silicate particles, such as:

- magnesium aluminium silicate particles, such as saponite or magnesium aluminium silicate hydrated with a sodium sulphate sold under the trade name Sumecton® by the company Kunimine;

- the magnesium silicate, hydroxyethyl cellulose, black cumin oil, marrow oil and phospholipids complex or Matipure® from Lucas Meyer, and

- mixtures thereof.

Preferred matting agents that may be used according to the invention include a pumpkin seed extract, a rice or corn starch, kaolinite, silicas, talc, polyamide powders, polyethylene powders, acrylic copolymer powders, expanded acrylic copolymer microspheres, silicone resin microbeads and mixed silicate particles, and mixtures thereof.

Fillers with a soft-focus effect These fillers may be any material capable of modifying and hiding wrinkles by virtue of its intrinsic physical properties. These fillers may especially modify wrinkles via a tensioning effect, a covering effect or a soft-focus effect. The following compounds may be given as examples: - porous silica microparticles, for instance the Silica Beads® SB150 and SB700 from Miyoshi with a mean size of 5 pm; the series H Sunspheres® from Asahi Glass, for instance Sunspheres H33, H51 with respective sizes of 3.5 and 5 pm;

- hollow hemispherical silicone resin particles such as NLK 500®, NLK 506® and NLK 510® from Takemoto Oil and Fat, especially described in EP-A-1 579 849;

- silicone resin powders, for instance the silicone resin Tospearl® 145A from GE Silicone, with a mean size of 4.5 pm;

- powders of acrylic polymers, especially of polymethyl (meth)acrylate, for instance the PMMA particles Jurimer MBI® from Ninon Junyoki, with a mean size of 8 pm, the hollow PMMA spheres sold under the name Covabead® LH85 by the company Wackherr, and vinylidene/acrylonitrile/methylene methacrylate expanded microspheres sold under the name Expancel®;

- wax powders, for instance the paraffin wax particles MicroEase® 1 14S from

MicroPowders, with a mean size of 7 pm;

- polyethylene powders, especially comprising at least one ethylene/acrylic acid copolymer, for instance the Flobeads® EA 209 E particles from Sumitomo, with a mean size of 10 pm;

- crosslinked elastomeric organopolysiloxane powders coated with silicone resin and especially with silsesquioxane resin, under the names KSP-100®, KSP- 101®, KSP-102®, KSP-103®, KSP-104® and KSP-105® by the company Shin- Etsu;

- talc/titanium dioxide/alumina/silica composite powders, for instance those sold under the name Coverleaf AR-80® by the company Catalyst & Chemicals;

- talc, mica, kaolin, lauryl glycine, starch powders crosslinked with octenyl succinate anhydride, boron nitride, polytetrafluoroethylene powders, precipitated calcium carbonate, magnesium hydrogen carbonate, barium sulphate, hydroxyapatite, calcium silicate, cerium dioxide and glass or ceramic microcapsules;

- hydrophilic or hydrophobic, synthetic or natural, mineral or organic fibres such as silk fibres, cotton fibres, wool fibres, flax fibres, cellulose fibres extracted especially from wood, vegetables or algae, polyamide (Nylon®) fibres, modified cellulose fibres, poly-p-phenyleneterephthamide fibres, acrylic fibres, polyolefin fibres, glass fibres, silica fibres, aramid fibres, carbon fibres, polytetrafluoroethylene (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 mixture of polymers, resorbable synthetic fibres, and mixtures thereof described in patent application EP 1 151 742;

- spherical elastomeric crosslinked silicones, for instance Trefil E-505C® or E- 506C® from Dow Corning;

- abrasive fillers, which, via a mechanical effect, smooth out the skin microrelief, such as abrasive silica, for instance Abrasif SP® from Semanez or nut or shell powders (for example of apricot or walnut, from Cosmetochem). The fillers with an effect on the signs of ageing are especially chosen from porous silica microparticles, hollow hemispherical silicone particles, silicone resin powders, acrylic copolymer powders, polyethylene powders, crosslinked elastomeric organopolysiloxane powders coated with silicone resin, talc/titanium dioxide/alumina/silica composite powders, precipitated calcium carbonate, magnesium hydrogen carbonate, barium sulphate, hydroxyapatite, calcium silicate, cerium dioxide, glass or ceramic microcapsules, and silk fibres or cotton fibres, and mixtures thereof.

The filler may be a soft-focus filler.

The term "soft-focus" filler means a filler which in addition gives the complexion transparency and a hazy effect. Preferably, the soft-focus fillers have a mean particle size of less than or equal to 15 microns. These particles may be in any form and in particular may be spherical or non-spherical. These fillers are more preferably non-spherical.

The soft-focus fillers may be chosen from silica and silicate powders, especially alumina powder, powders of polymethyl methacrylate (PMMA) type, talc, silica/Ti02 or silica/zinc oxide composites, polyethylene powders, starch powders, polyamide powders, styrene/acrylic copolymer powders and silicone elastomers, and mixtures thereof.

Mention may be made in particular of talc with a number-average size of less than or equal to 3 microns, for example talc with a number-average size of 1 .8 microns and especially the product sold under the trade name Talc P3® by the company Nippon Talc, Nylon® 12 powder, especially the product sold under the name Orgasol 2002 Extra D Nat Cos® by the company Atochem, silica particles 1 % to 2% surface-treated with a mineral wax (INCI name: hydrated silica (and) paraffin) such as the products sold by the company Degussa, amorphous silica microspheres, such as the products sold under the name Sunsphere, for example of reference H-53® by the company Asahi Glass, and silica microbeads such as those sold under the name SB-700® or SB-150® by the company Miyoshi, this list not being limiting.

The concentration of these fillers with an effect on the signs of ageing in the compositions according to the invention may be between 0.1 % and 40%, or even between 0.1 % and 20% by weight, relative to the total weight of the composition.

Agents for promoting the naturally pinkish coloration of the skin

Mention may be made especially of:

- a self-tanning agent, i.e. an agent which, when applied to the skin, especially to the face, can produce a tan effect that is more or less similar in appearance to that which may result from prolonged exposure to the sun (natural tan) or under a UV lamp;

- an additional colouring agent, i.e. any compound that has particular affinity for the skin, which allows it to give the skin a lasting, non-covering coloration (i.e. that does not have a tendency to opacify the skin) and that is not removed either with water or using a solvent, and that withstands both rubbing and washing with a solution containing surfactants. Such a lasting coloration is thus distinguished from the superficial and transient coloration provided, for example, by a makeup pigment;

and mixtures thereof. Examples of self-tanning agents that may especially be mentioned include:

dihydroxyacetone (DHA),

erythrulose, and

the combination of a catalytic system formed from:

manganese and/or zinc salts and oxides, and

alkali metal and/or alkaline-earth metal hydrogen carbonates.

The self-tanning agents are generally chosen from monocarbonyl or polycarbonyl compounds, for instance isatin, alloxan, ninhydrin, glyceraldehyde, mesotartaric aldehyde, glutaraldehyde, erythrulose, pyrazolin-4,5-dione derivatives as described in patent application FR 2 466 492 and WO 97/35842, dihydroxyacetone (DHA) and 4,4-dihydroxypyrazolin-5-one derivatives as described in patent application EP 903 342. DHA will preferably be used. DHA can be used in free and/or encapsulated form, for example encapsulated in lipid vesicules, such as liposomes, described in particular in patent application WO 97/25970.

In general, the self-tanning agent is present in an amount ranging from 0.01 % to 20% by weight and preferably in an amount of between 0.1 % and 10% of the total weight of the composition.

Other dyes that allow modification of the colour produced by the self-tanning agent may also be used.

These dyes may be chosen from synthetic or natural direct dyes.

These dyes may be chosen, for example, from red or orange dyes of the fluorane type such as those described in patent application FR 2 840 806. Mention may be made, for example, of the following dyes:

- tetrabromofluorescein or eosin known under the CTFA name: CI 45380 or Red 21

- phloxine B known under the CTFA name: CI 45410 or Red 27

- diiodofluorescein known under the CTFA name: CI 45425 or Orange 10;

- dibromofluorescein known under the CTFA name: CI 45370 or Orange 5;

- the sodium salt of tetrabromofluorescein known under the CTFA name: CI 45380 (Na salt) or Red 22;

- the sodium salt of phloxine B known under the CTFA name: CI 45410 (Na salt) or Red 28;

- the sodium salt of diiodofluorescein known under the CTFA name: CI 45425 (Na salt) or Orange 1 1 ;

- erythrosine known under the CTFA name: CI 45430 or Acid Red 51 ;

- phloxine known under the CTFA name: CI 45405 or Acid Red 98. These dyes may also be chosen from anthraquinones, caramel, carmine, carbon black, azulene blues, methoxalene, trioxalene, guajazulene, chamuzulene, rose Bengal, eosin 10B, cyanosine and daphnin.

These dyes may also be chosen from indole derivatives, for instance the monohydroxyindoles as described in patent FR 2 651 126 (i.e.: 4-, 5-, 6- or 7- hydroxyindole) or the dihydroxyindoles as described in patent EP-B-0 425 324 (i.e.: 5,6-dihydroxyindole, 2-methyl-5,6-dihydroxyindole, 3-methyl-5,6- dihydroxyindole or 2,3-dimethyl-5,6-dihydroxyindole). Abrasive fillers or exfoliants

As exfoliants that may be used in compositions according to the invention, examples that may be mentioned include exfoliant or scrubbing particles of mineral, plant or organic origin. Thus, use may be made, for example, of polyethylene beads or powder, Nylon powder, polyvinyl chloride powder, pumice powder, ground apricot kernels or walnut shells, sawdust, glass beads and alumina, and mixtures thereof. Mention may also be made of Exfogreen® from Solabia (bamboo extract), extracts of strawberry achenes (Strawberry Achenes from Greentech), peach kernel powder, apricot kernel powder, and finally, in the field of plant powders with an abrasive effect, mention may be made of cranberry kernel powder.

As abrasive fillers or exfoliants that are preferred according to the invention, mention will be made of peach kernel powder, apricot kernel powder, cranberry kernel powder, strawberry achene extracts and bamboo extracts.

The examples that follow serve to illustrate the invention without, however, being limiting in nature. EXAMPLE A: Preparation of octyl 4-(butylamino)-2-methyl-4-oxobutanoate

(compound i):

(i)

First step: Preparation of 4-(butylamino)-2-methyl-4-oxobutanoic acid:

At room temperature, methylsuccininic anhydride (9.23 g, 0.081 mol) is dissolved in 50 ml of THF. It is cooled in an iced water bath and n-butylamine (8 ml, 0.081 mol) is poured in rapidly. When the exothermic reaction has finished, the reaction mixture is left at room temperature for 12 hours. The reaction mixture is stripped of its solvent by vacuum evaporation. Thus, 15 g (quantitative yield) of 4- (butylamino)-2-methyl-4-oxobutanoic acid are obtained in the form of a pale yellow oil and are used in the following step.

Second step: Preparation of octyl 4-(butylamino)-2-methyl-4-oxobutanoate:

The mixture of 2.39 g of the preceding product (0.0123 mol), 150 mg of DMAP and 1 .95 ml of n-octanol (0.0123 mol) in 30 ml of dichloromethane is cooled to 0°C by an iced water bath. Added thereto are 2.54 g of DCC (0.0123 mol) and also 20 ml of dichloromethane. The reaction mixture is left at room temperature for 24 hours. The reaction mixture is filtered over a no. 3 frit and the solid rinsed with dichloromethane. The solvent of the filtrate is evaporated off under vacuum. A whiteish residue is obtained. This residue is chromatographed on a silica column (gradient of eluents: heptane/AcOEt 80:20 to 70:30). 2.45 g (yield: 66%) of clean fractions of the derivative of Example 1 are thus obtained in the form of a colourless oil.

PHOTOSTABILITY TESTS

The photostabilizing effect of a monoester-monoamide compound of 2- methylsuccinate of formula (I) [formula (j)] in accordance with the invention was evaluated with respect to the dibenzoylmethane derivative: Butyl methoxy dibenzoylmethane (avobenzone) sold under the trade name Parsol 1789 by the company DSM Nutritional Products.

The photostabilizing effect of this monoester-monoamide compound of 2- methylsuccinate of formula (j) was also compared with 2 amides that do not fall under the definition of formula (I) (comparative examples 1 and 2):

arative 2)

5L-205

PRINCIPLE OF THE METHOD:

The remaining percentage of dibenzoylmethane derivative after exposure to a solar simulator of a formula spread as films about 20 pm thick is measured.

The evaluation is performed by HPLC analysis of the screening agent in solution, after extraction of the films, by comparing the irradiated and non-irradiated samples.

EQUIPMENT AND METHOD:

Solar simulator: Oriel 1000 W machine equipped with a 4-inch output, with a 81017 filter and a dichroic mirror. The samples are exposed in the horizontal position.

UV-meter: Osram Centra machine equipped with two reading heads, one for UV- A, the other for UV-B. The simulator/UV-meter assembly is calibrated annually by spectroradiometry. Irradiance measurements taken at the start and end of exposure by placing the reading heads at the position of the sample.

The irradiances are:

0.35-0.45 mW/cm² in UV-B

16-18 mW/cm² in UV-A.

The residual content of butyl methoxy dibenzoylmethane is measured by chromatography: HPLC chain with diode array detector. COMMON SUPPORT

The monoester-monoamide compounds of 2-methylsuccinic acid are introduced into the common support defined above at a concentration of 4% by weight in the presence of 1 % by weight of butyl methoxy dibenzoylmethane of composition:

The percentage of butyl methoxy dibenzoylmethane (avobenzone) remaining after irradiation in the same support containing no compound of formula (I) is also measured: (Comparative example 3)

IMPLEMENTATION OF THE PHOTOSTABILITY TESTS

Approximately 20 mg of each formula tested are spread over a surface area of 10 cm² on an etched face of a disc of molten silica. The exact amount is determined by weighing.

3 films are exposed to the solar simulator and 3 others serve as a control.

The samples are exposed 3 at a time to the light of the solar simulator for a period of time sufficient to deliver a UV-A dose equal to 12 J corrected with respect to the sensitivity of the UV-meter corresponding to the degradation of approximately 50% of the butyl methoxy dibenzoylmethane (avobenzone) in the absence of protective agent. At the end of the exposure, each support disc is introduced into a 600 ml jar with 10 ml of a suitable solvent (in general, EtOH); the assembly is placed in an ultrasonic tank for 5 minutes.

The solution is then transferred into bottles suitable for the support that is compatible with the HPLC analysis machine used. The analytical conditions may be adjusted as a function of the active agent tested.

The percentage remaining is calculated from averages obtained from the irradiated and non-irradiated samples, as described below:

TABLE I

Stabilities of the emulsions over time:

The monoester-monoamide derivative of 2-methylsuccinic acid of formula (j) of Example 1 according to the invention has a photostabilizing effect with respect to the dibenzoylmethane derivative that is substantially greater than that obtained with comparative compound 2 from the prior art and a photostabilizing effect equivalent to that of comparative compound 1 from the prior art; in the latter case, the emulsion is stable over time for the compound (j) of the invention whereas the emulsion breaks in the case of comparative compound 1 .

FORMULATION EXAMPLES

The following formulations were prepared, the amounts are expressed as weight percentages relative to the total weight of the composition.

Composition Ex. 3 Ex. 4

Phase A

Polydimethylsiloxane 0.5 0.5

Preserving agents 1 1

Stearic acid 1 .5 1 .5

Glyceryl monostearate/PEG-100 stearate mixture 1 1

Mixture of cetylstearyl glucoside and of cetyl and

2 2 stearyl alcohols

Cetyl alcohol 0.5 0.5

Compound (j) 20 15

1 -(4-methoxy-1 -benzofuran-5-yl)-3- phenylpropane-1 ,3-dione (Pongamol). 5 Butyl methoxy dibenzoylmethane (avobenzone) - 5

Phase B

Deionized water qs 100 qs 100

Glycerol 5 5

Xanthan gum 0.2 0.2

Monocetyl phosphate 1 1

Phase C

Isohexadecane 1 1

Acrylic acid/stearyl methacrylate copolymer 0.2 0.2

Triethanolamine qs pH qs pH

Procedure:

The aqueous phase (Phase B) comprising all of its ingredients is heated to 80°C in a water bath. The fatty phase (Phase A) comprising all of its ingredients is heated to 80°C in a water bath. A is emulsified in B with stirring of rotor-stator type (device from Moritz). Phase C is incorporated and the mixture is allowed to return to ambient temperature with moderate stirring. The triethanolamine is introduced so as to adjust the pH to the value desired at the end of manufacture. The anti-sun emulsions obtained are stable during storage and do not have crystals or precipitates.

Claims

1. Composition comprising, in a cosmetically acceptable support, at least one UV- screening system, characterized in that it comprises:

(a) at least one UV-A screening agent of dibenzoylmethane derivative type and

(b) at least one monoester-monoamide derivative of methylsuccinic acid of formula (I) or an op

in which:

Ri and R₂, which are identical or different, denote a linear or branched C1-C20 alkyl radical, or a C5-C6 cycloalkyl radical, optionally substituted with C1-C3 alkyl radicals,

X and Y denote, independently of one another, -0- or -N(R₃)-, with R₃ denoting hydrogen or a linear or branched C1-C20 alkyl radical,

X and Y cannot simultaneously represent 0 or NR₃;

when X or Y = NR₃, Ri and R₃, or R₂ and R₃, may form, with the nitrogen that bears them, a 5- to 6-membered heterocycle optionally substituted with one or more identical or different Ci-C₃ alkyl radicals.

2. Composition according to Claim 1 , in which the compound of formula (I) is chosen from those for which:

Ri and R₂, which are identical or different, denote a linear or branched d-C-io alkyl radical, or a C5-C6 cycloalkyl radical, optionally substituted with Ci-C₃ alkyl radicals,

X and Y denote, independently of one another, -0- or -N(R₃)-, with R₃ denoting hydrogen or a linear or branched d-C-io alkyl radical,

X and Y cannot simultaneously represent 0 or NR₃;

when X or Y = NR₃, Ri and R₃, or R₂ and R₃, may form, with the nitrogen that bears them, a 5- to 6-membered heterocycle optionally substituted with one or more identical or different Ci-C₃ alkyl radicals.

3. Composition according to Claim 1 or 2, in which the compound of formula (I) is chosen from the following compounds (a) to (j) or isomers thereof:

(i)

4. Composition according to Claim 3, in which the compound of formula (I) is chosen from the compounds (c), (d) and (j).

5. Composition according to any one of Claims 1 to 4, in which the derivative(s) of formula (I) is (are) present in contents ranging from 1 % to 30% by weight and more preferentially from 3% to 20% by weight relative to the total weight of the composition.

6. Composition according to any one of Claims 1 to 5, in which the dibenzoylmethane derivative is chosen from:

- 2-methyldibenzoylmethane,

- 4-methyldibenzoylmethane,

- 4-isopropyldibenzoylmethane,

- 4-fe/f-butyldibenzoylmethane,

- 2,4-dimethyldibenzoylmethane,

- 2,5-dimethyldibenzoylmethane,

- 4,4'-diisopropyldibenzoylmethane,

- 4,4'-dimethoxydibenzoylmethane,

- 4-ie f-butyl-4'-methoxydibenzoylmethane,

- 2-methyl-5-isopropyl-4'-methoxydibenzoylmethane,

- 2-methyl-5-ie f-butyl-4'-methoxydibenzoylmethane,

- 2,4-dimethyl-4'-methoxydibenzoylmethane,

- 2,6-dimethyl-4-ie f-butyl-4'-methoxydibenzoylmethane,

- 1 -(4-methoxy-1 -benzofuran-5-yl)-3-phenylpropane-1 ,3-dione (Pongamol).

7. Composition according to any one of Claims 1 to 6, in which the dibenzoylmethane derivative is 4-ie f-butyl-4'-methoxydibenzoylmethane, or butyl methoxy dibenzoy

8. Composition according to any one of Claims 1 to 7, characterized in that the dibenzoylmethane derivative(s) is (are) present in contents ranging from 0.01 % to 20% by weight and more preferentially from 0.1 % to 10% by weight and more preferentially still from 0.1 % to 6% by weight relative to the total weight of the composition.

9. Composition according to any one of Claims 1 to 8, characterized in that it also contains other organic or inorganic screening agents active in the UV-A and/or UV-B regions that are water-soluble or liposoluble or else insoluble in the cosmetic solvents commonly used.

10. Composition according to Claim 9, in which the additional organic UV- Screening agents are chosen from anthranilic derivatives; cinnamic derivatives; salicylic derivatives; benzylidene camphor derivatives; benzophenone derivatives; β,β-diphenylacrylate derivatives; triazine derivatives; phenylbenzotriazole derivatives; benzalmalonate derivatives; phenylbenzimidazole derivatives; imidazoline derivatives; bis-benzoazolyl derivatives; p-aminobenzoic acid (PABA) derivatives; methylenebis(hydroxy- phenylbenzotriazole) derivatives; benzoxazole derivatives; screening polymers and screening silicones; -alkylstyrene-based dimers; 4,4-diarylbutadienes; liposoluble merocyanine derivatives; and mixtures thereof.

11. Composition according to Claim 9 or 10, characterized in that the additional organic UV-Screening agent(s) is (are) chosen from the following compounds: ethylhexyl methoxycinnamate,

homosalate,

ethylhexyl salicylate,

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 tetrasulfonate,

ethylhexyl triazone,

bis-ethylhexyloxyphenol methoxyphenyl triazine,

diethylhexyl butamido triazone,

2,4,6-tris(biphenyl-4-yl)-1 ,3,5-triazine,

2,4,6-tris(dineopentyl 4'-aminobenzalmalonate)-s-triazine,

2,4,6-tris(diisobutyl 4'-aminobenzalmalonate)-s-triazine,

2,4-bis(dineopentyl 4'-aminobenzalmalonate)-6-(n-butyl 4'-aminobenzoate)-s- triazine,

2,4-bis(n-butyl 4'-aminobenzoate)-6-[(3-{1 ,3,3,3-tetramethyl-1 -[(trimethylsilyl)- oxy]disiloxanyl}propyl)amino]-s-triazine,

methylene bis(benzotriazolyl) tetramethylbutylphenol,

drometrizole trisiloxane,

polysilicone-15,

dineopentyl 4'-methoxybenzalmalonate,

1 , 1 -dicarboxy(2,2'-dimethylpropyl)-4,4-diphenylbutadiene, ,4-Bis[5-(1 , 1 -dimethylpropyl)benzoxazol-2-yl-(4-phenyl)imino]-6-(2- ethylhexyl)imino-1 ,3,5-triazine,

and mixtures thereof.

12. Composition according to Claim 9, characterized in that the additional inorganic screening agents are coated or uncoated metal oxide pigments.

13. Process for improving the chemical stability towards UV radiation of at least one UV-A screening agent of dibenzoylmethane derivative type, characterized in that said dibenzoylmethane derivative is combined with an effective amount of at least one monoester-monoamide derivative of methylsuccinic acid of formula (I) or an optical or geometric isomer thereof as defined in any one of Claims 1 to 4.

14. Compound (j) of the following structure:

15. Use of a monoester-monoamide compound of methylsuccinic acid of formula (I) or an isomer thereof as defined in any one of Claims 1 to 4, in a composition comprising, in a cosmetically acceptable support, at least one dibenzoylmethane derivative, for the purpose of improving the efficacy of said composition with respect to UV-A rays.