WO2025252543A1

WO2025252543A1 - Oil-in-water emulsion cosmetic composition based on a lamellar structure comprising a thiopyridinone compound, a reducing agent and a chelating agent

Info

Publication number: WO2025252543A1
Application number: PCT/EP2025/064650
Authority: WO
Inventors: Carole Guiramand; Muriel ISOIR-INGREZ; Romain TACHON
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 2024-06-03
Filing date: 2025-05-27
Publication date: 2025-12-11
Anticipated expiration: 2026-12-03
Also published as: FR3162632A1

Abstract

The invention relates to a composition, notably a cosmetic composition, comprising: (1) one or more compounds chosen from the compounds of formula (I), the tautomers of formula (I'), salts thereof, solvates thereof, such as hydrates thereof, optical isomers thereof, racemates thereof, and mixtures thereof; (2) one or more saturated C₁₆-C₂₂ fatty alcohol(s); (3) one or more anionic surfactant(s) comprising at least one C₁₆-C₂₂ hydrocarbon chain; (4) one or more reducing agent(s), mesomeric forms thereof, solvates thereof such as hydrates; and (5) one or more chelating agent(s) other than (4).

Description

DESCRIPTION

TITLE: Oil-in-water emulsion cosmetic composition based on a lamellar structure comprising a thiopyridinone compound, a reducing agent and a chelating agent

The invention relates to a composition, in particular a cosmetic composition, in the form of an oil-in-water emulsion, based on a structure of specific lamellar phases comprising (1) at least one thiopyridinone compound, (4) at least one reducing agent, which is preferably inorganic, and (5) at least one chelating agent other than (4), which is preferably organic.

The type of presentation form considered in the present invention, namely a lamellar-phase oil-in-water emulsion, notably requires the presence of (2) at least one saturated C16-C22 fatty alcohol and (3) at least one anionic surfactant comprising at least one C16-C22 hydrocarbon chain.

This type of presentation form has notably been described in patent applications WO 2018/108878 and WO 2020/002538, for developing compositions intended for masking skin imperfections, moisturizing the skin and/or treating the signs of skin aging, in particular the appearance of fine lines and deep wrinkles, which increase with age.

In addition, at various periods in their life, some people see the appearance on their skin, and more particularly on their face and hands, of darker and/or more colored spots, which give the skin its heterogeneity. These spots are due to a high concentration of melanin in the keratinocytes located on the surface of the skin.

The use of harmless topical depigmenting substances having good efficacy in the treatment of pigment spots is particularly desired. For example, arbutin, niacinamide and kojic acid are known as skin depigmenting agents.

In this respect, certain thiopyridinone compounds prove to be particularly advantageous because they exhibit good depigmenting activity, even at low concentrations, as indicated in several patent applications such as WO 2017/102349. Indeed, these thiopyridinone compounds can have strong depigmenting or whitening effects by reducing the production of melanin.

However, these thiopyridinone compounds possess physicochemical properties that make them difficult to (photo)stabilize. This type of problem has notably been described in patent application FR3137834 A1.

In addition, oil-in-water emulsion compositions based on a specific lamellar structure are difficult to stabilize physicochemically; this is due notably to the use of a particular surfactant.

It is therefore difficult to obtain cosmetic compositions of the oil-in-water emulsion type, based on a lamellar structure comprising at least one thiopyridinone compound, which remain physicochemically stable, and in which said thiopyridinone compound is not degraded, in particular under the action of UV radiation.

Consequently, there remains the need to provide cosmetic compositions of the oil-in-water emulsion type, based on a lamellar structure, comprising a photostable thiopyridinone compound and which exhibit good sensory properties, such the feel after application or little change in odour over time, and that make it possible to give the skin lightening and whitening effects. An aim of the present invention is also the development of compositions with lamellar-phase oil-in-water architecture in accordance with the preceding requirements, which have satisfactory stability, in particular stability evaluated after 24 h at 25°C and after two months of storage at 4°C, 25°C and 45°C.

The invention relates to a composition, notably a cosmetic composition, comprising:

(1) one or more compounds chosen from the compounds of formula (I) below, the tautomers of formula (I’) below, salts thereof, solvates thereof, such as hydrates thereof, optical isomers thereof, racemates thereof, and mixtures thereof:

[Chem. 1] wherein Ri denotes a radical chosen from a) a hydrogen atom, and b) a saturated linear C1-C10 or branched C3 -C10 alkyl group optionally substituted with one or more groups, which may be identical or different, chosen from i) -O-R3, and ii) -S-R3, and R2 denotes a radical chosen from a) a hydrogen atom, b) a saturated linear C1-C12 or branched C3-C12 or cyclic C3-C8 hydrocarbon group optionally substituted with one or more groups, which may be identical or different, chosen from i) -O-R3, ii) -S-R3, iii) -C(O)-O-R3, and iv) a C5- C12 aryl group optionally substituted with one or more hydroxyls and/or with one or more Ci-Cs alkoxy radicals, and c) a C5-C12 aryl group optionally substituted with one or more hydroxyls and/or with one or more Ci-Cs alkoxy radicals, wherein R3 denotes a radical chosen from a) a hydrogen atom, and b) a saturated linear C1-C10 or branched C3-C10 alkyl group;

(2) one or more saturated C16-C22 fatty alcohol(s);

(3) one or more anionic surfactant(s) comprising at least one C16-C22 hydrocarbon chain;

(4) one or more reducing agent(s); and

(5) one or more chelating agent(s) other than (4), which makes it possible to obtain good composition stability properties and also good photostability of the thiopyridinone compound (1).

The invention also relates to a process for treating keratin materials, preferably a process for whitening, in particular facial and/or bodily skin, comprising the application of said composition to said keratin materials.

Finally, the invention relates to the use of such a composition for treating keratin materials, in particular for caring for bodily and/or facial skin.

It has been found, surprisingly, that a composition, notably a cosmetic composition, comprising:

[Chem. 2]

0) (D wherein R1 denotes a radical chosen from a) a hydrogen atom, and b) a saturated linear C1-C10 or branched C3 -C10 alkyl group optionally substituted with one or more groups, which may be identical or different, chosen from i) -O-R3, and ii) -S-R3, and R2 denotes a radical chosen from a) a hydrogen atom, b) a saturated linear C1-C12 or branched C3-C12 or cyclic C3-C8 hydrocarbon group optionally substituted with one or more groups, which may be identical or different, chosen from i) -O-R3, ii) -S-R3, iii) -C(O)-O-R3, and iv) a C5- C12 aryl group optionally substituted with one or more hydroxyls and/or with one or more Ci-Cs alkoxy radicals, and c) a C5-C12 aryl group optionally substituted with one or more hydroxyls and/or with one or more Ci-Cs alkoxy radicals, wherein R3 denotes a radical chosen from a) a hydrogen atom, and b) a saturated linear C1-C10 or branched C3-C10 alkyl group;

(2) one or more saturated C16-C22 fatty alcohol(s);

(4) one or more inorganic reducing agent(s), mesomeric forms thereof, solvates thereof such as hydrates, or mixtures thereof; and

(5) one or more chelating agent(s) other than (4), which makes it possible to obtain good composition stability properties and also good photostability of the thiopyridinone compound.

A composition can be considered to remain stable when its properties, after two months of storage at 4°C, 25°C and 45°C, remain close to those characterized at 24 h at 25°C.

Thus, a subject of the present invention is a cosmetic composition comprising:

[Chem. 3]

(i) (r) wherein Ri denotes a radical chosen from a) a hydrogen atom, and b) a saturated linear C1-C10 or branched C3 -C10 alkyl group optionally substituted with one or more groups, which may be identical or different, chosen from i) -O-R3, and ii) -S-R3, and R2 denotes a radical chosen from a) a hydrogen atom, b) a saturated linear C1-C12 or branched C3-C12 or cyclic C3-C8 hydrocarbon group optionally substituted with one or more groups, which may be identical or different, chosen from i) -O-R3, ii) -S-R3, iii) -C(O)-O-R3, and iv) a C5- C12 aryl group optionally substituted with one or more hydroxyls and/or with one or more Ci-Cs alkoxy radicals, and c) a C5-C12 aryl group optionally substituted with one or more hydroxyls and/or with one or more Ci-Cs alkoxy radicals, wherein R3 denotes a radical chosen from a) a hydrogen atom, and b) a saturated linear C1-C10 or branched C3-C10 alkyl group;

(2) one or more saturated C16-C22 fatty alcohol(s);

(4) one or more reducing agent(s), preferably inorganic reducing agent(s); and

(5) one or more chelating agent(s), preferably organic chelating agent(s), other than (4).

In a particular embodiment, the composition according to the invention is intended for topical application, notably to keratin materials, in particular the skin.

It notably comprises a “cosmetically acceptable" medium, also known as a “physiologically acceptable" medium, i.e. a medium that is compatible with all keratin materials, in particular the skin.

For the purposes of the present invention, the term “keratin materials" means the skin and its integuments.

The term “skin" means human skin, notably of the face and/or body, or the scalp.

The term “integuments" means human keratin fibers, notably the eyelashes, the eyebrows, the nails and the hair, in particular the eyelashes and the hair.

In that which will follow, and unless otherwise indicated, the limits of a range of values are included in this range, in particular in the expressions “of between” and “ranging from ... to

JJ

Moreover, the expression “at least one" used in the present description is equivalent to the expression “one or more".

(1) Thiopyridinone compound(s)

The composition according to the present invention comprises one or more thyropyridinone compound(s) (1). Two or more thiopyridinone compounds (1) may be used in combination. Thus, a single type of thiopyridinone compound (1) or a combination of different types of thiopyridinone compounds (1) can be used.

The thiopyridinone compound (1) is chosen from the compounds of formula (I) below, tautomers of formula (I’) below, salts thereof, solvates thereof, such as hydrates thereof, optical isomers thereof, racemates thereof, and mixtures thereof:

[Chem. 4] formulae (I) and (I¹) wherein:

Ri denotes a radical chosen from: a) a hydrogen atom, and b) a saturated linear C1-C10 or branched C3-C10 alkyl group optionally substituted with one or more groups which may be identical or different, chosen from: i) -O-R3, and ii) -S-R3, and

R2 denotes a radical chosen from: a) a hydrogen atom, b) a saturated linear C1-C12 or branched C3-C12 or cyclic C3-C8 hydrocarbon group optionally substituted with one or more groups, which may be identical or different, chosen from: i) -O-R3; ii) -S-R₃; iii) -C(O)-O-R3; and iv) a C5-C12 aryl group, optionally substituted with one or more hydroxyls and/or with one or more Ci-Cs alkoxy radicals; and c) a C5-C12 aryl group, optionally substituted with one or more hydroxyls and/or with one or more Ci-Cs alkoxy radicals; wherein R3 denotes a radical chosen from: a) a hydrogen atom, and b) a saturated linear C1-C10 or branched C3-C10 alkyl group.

Below, for the purposes of the present invention and unless otherwise indicated:

- a "saturated linear C1-C12 or branched C3-C12 hydrocarbon group" is equivalent to a "linear (C1-C12) or branched (C3-C12) alkyl group" which corresponds to a saturated linear C1-C12 or branched C3-C12 hydrocarbon group, preferably a linear C1-C10 or branched C3-C10 hydrocarbon group, and more preferably a linear Ci-Ce or branched C3-C6 hydrocarbon group; preferentially, the linear or branched groups may be chosen from methyl, ethyl, propyl, isopropyl, butyl, isobutyl and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl and decyl groups; more preferentially, the saturated linear or branched alkyl groups may be chosen from methyl, ethyl, propyl, isopropyl, butyl, isobutyl and tert-butyl, pentyl, hexyl, heptyl and octyl groups, such as methyl, ethyl, n-pentyl, n-nonyl and isobutyl groups;

- a saturated "cyclic Cs-Ca" hydrocarbon group is a monocyclic or bicyclic cycloalkyl group containing from 3 to 8 carbon atoms, and in particular is a monocyclic C5 to C7 cycloalkyl group such as a cyclohexyl group;

- an "alkoxy radical' is an alkyl-oxy radical for which the alkyl radical is a linear or branched C1-C16 hydrocarbon radical, and preferentially a Ci-Cs hydrocarbon radical;

- when the alkoxy group is optionally substituted, this implies that the alkyl group is optionally substituted as defined above;

- an "aryl" group represents a monocyclic or fused or non-fused bicyclic carbon-based group comprising from 5 to 12 carbon atoms, preferably from 6 to 10 carbon atoms, and wherein at least one ring is aromatic; preferentially, the aryl radical is a phenyl, biphenyl or naphthyl group, more preferably a phenyl group; and

- the term "inclusive" for a concentration range means that the limits of that range are within the defined range.

The salts of the compounds of formula (I), (I’), (II) or (II’) as defined below comprise the conventional non-toxic salts of said compounds, such as those formed from an organic or inorganic acid or from an organic or inorganic base.

As salts of the compounds of formula (I), (I¹), (II) or (II¹), mention may be made of the salts obtained by adding the compound of formula (I) or (II) to:

- a mineral base, such as sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonium hydroxide, magnesium hydroxide, lithium hydroxide, or sodium, potassium or calcium carbonate or hydrogen carbonate, for example; or - an organic base such as a primary, secondary or tertiary alkylamine, for example triethylamine or butylamine. This primary, secondary or tertiary alkylamine may comprise one or more nitrogen and/or oxygen atoms and may thus comprise, for example, one or more alcohol functions. Mention may be made in particular of 2-amino-2-methylpropanol, ethanolamine, triethanolamine, 2-dimethylaminopropanol, 2-amino-2-(hydroxymethyl)-1 ,3- propanediol and 3-(dimethylamino)propylamine.

Mention may also be made of the salts of amino acids, for example lysine, arginine, guanidine, glutamic acid and aspartic acid. Advantageously, the salts of the compounds of formula (I) or (II) (when they comprise a carboxyl group) may be chosen from alkali metal or alkaline-earth metal salts such as sodium, potassium, calcium or magnesium salts and ammonium salts.

An "organic or inorganic acid salt' is more particularly chosen from salts chosen from among a salt derived from i) hydrochloric acid HCI, ii) hydrobromic acid HBr, iii) sulfuric acid H2SO4, iv) alkylsulfonic acids: Alk-S(O)2OH such as methanesulfonic acid and ethanesulfonic acid; v) arylsulfonic acids: Ar-S(O)₂OH such as benzenesulfonic acid and toluenesulfonic acid; vi) citric acid ; vii) succinic acid ; viii) tartaric acid ; ix) lactic acid; x) alkoxysulfinic acids : Alk-O-S(O)OH, such as methoxysulfinic acid and ethoxysulfinic acid; xi) aryloxysulfinic acids, such as tolueneoxysulfinic acid and phenoxysulfinic acid; xii) phosphoric acid H3PO4; xiii) acetic acid CH3C(O)OH; xiv) triflic acid CF3SO3H; and xv) tetrafluoroboric acid HBF4.

The acceptable solvates of the compounds described in the specification comprise conventional solvates such as those formed during the preparation of said compounds owing to the presence of solvents. Examples that may be mentioned include solvates due to the presence of water or of linear or branched alcohols, such as ethanol or isopropanol.

The optical isomers are in particular enantiomers and diastereoisomers.

Compound (I’) is the tautomeric form of compound (I) when a tautomeric equilibrium exists according to the following scheme:

[Chem. 5]

According to one embodiment of the present invention, Ri represents a hydrogen atom.

According to another embodiment of the present invention, Ri represents a linear (C1-C10) alkyl group or a branched (C3-C10) alkyl group, in particular a linear (Ci-Ce) alkyl group or a branched (Ca-Ce) alkyl group, such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably ethyl. In particular, said alkyl group of Ri is not substituted.

According to one embodiment of the present invention, R2 represents a hydrogen atom.

According to one embodiment of the present invention, R₂ represents a linear (C1-C10) or branched (C3-C10) alkyl group, in particular a linear (Ci-Ce) or branched (Ca-Ce) alkyl group, such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably methyl or ethyl; said alkyl group of R₂ not being substituted.

According to another embodiment of the present invention, R₂ represents a linear (C1-C10) alkyl group or a branched (C3-C10) alkyl group, in particular a linear (Ci-Ce) alkyl group or a branched (Ca-Ce) alkyl group, such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably methyl or ethyl; said alkyl group being substituted with one or more groups chosen from i), ii), iii) and iv) as defined above. Preferably, said alkyl group is substituted with one or two groups chosen from i), ii) and iii), more preferably with one or two groups chosen from i) and iii), better still substituted with one group iii) such as carboxy.

Another variant for the radical R₂ is that said alkyl group is substituted with a group iv), in particular substituted with a phenyl group.

According to another embodiment of the present invention, R₂ represents a (Ca-Cs) cycloalkyl group, preferably a (C5-C7) cycloalkyl group such as cyclohexyl.

According to another embodiment of the present invention, R₂ represents a Cs-Ci₂ aryl group optionally substituted with one or more hydroxyls and/or with one or more Ci-Cs alkoxy radicals, preferably a phenyl group, in particular which is not substituted.

According to one embodiment, R3 represents a hydrogen atom.

According to another embodiment, R3 represents a saturated linear C1-C10 or branched C3- C10 alkyl group; in particular a linear (Ci-Ce) or branched (Cs-Ce) alkyl group, preferably a (C1-C4) alkyl group such as the methyl group.

Preferably, the compounds of formula (I) and the tautomer (I’) or salts thereof, optical isomers, racemates and/or solvates thereof, such as hydrates thereof and derivatives thereof, alone or as a mixture, have the following meanings:

R1 denotes a radical chosen from: a) a hydrogen atom, and b) a saturated linear Ci-Ce or branched C3-C6 alkyl group optionally substituted with one or more groups which may be identical or different, chosen from: i) -O-R3, and ii) -S-R₃; preferably optionally substituted with one or more groups i);

R₂ denotes a radical chosen from: a) a hydrogen atom; b) a saturated linear C1-C10 or branched C3-C10 or cyclic C3-C8, such as Cs-Ce, hydrocarbon group, optionally substituted with one or more groups which may be identical or different and are chosen from: i) -O-R3; ii) -S-R₃; iii) -C(O)-O-R3; and iv) a phenyl group optionally substituted with one or more hydroxyls and/or by one or more C1-C4 alkoxy radicals such as methoxy, preferably substituted with one or more groups chosen from i) and iii), preferably iii) such as carboxy; and

R3 denotes a radical chosen from: a) a hydrogen atom, and b) a saturated linear Ci-Ce or branched C3-C6 alkyl group.

Preferentially, the compounds of formula (I) and the tautomer (I’) or salts thereof, optical isomers and racemates thereof and/or solvates thereof, such as hydrates thereof, alone or as a mixture, have the following meanings: Ri denotes a radical chosen from: a) a hydrogen atom, and b) a saturated linear C1-C4 or branched C3-C4 alkyl group optionally substituted with one or more groups which may be identical or different and are chosen from i) -OR3 and more preferably unsubstituted;

R2 denotes a radical chosen from: a) a hydrogen atom; and b) a saturated linear C1-C10 or branched C3-C10 or cyclic C3-C8, such as Cs-Ce, hydrocarbon group, optionally substituted with one or more groups which may be identical or different and are chosen from: i) -O-R3; iii) -C(O)-O-R₃; iv) a C5-C12 aryl group, optionally substituted with one or more hydroxyls and/or with one or more C1-C4 alkoxy radicals; and

R₃ denotes a radical chosen from a) a hydrogen atom, and b) a saturated linear C1-C4 or branched C3-C4 alkyl group such as methyl or ethyl.

Preferentially, the compounds of formula (I) and the tautomer (I’) or salts thereof, optical isomers and racemates thereof and/or solvates thereof, such as hydrates thereof, alone or as a mixture, have the following meanings:

R1 is a hydrogen atom; and

R₂ denotes a radical chosen from: a) a hydrogen atom, and b) a saturated linear C1-C5 or branched C3-C5 or cyclic C3-C8, such as Cs-Ce, hydrocarbon group substituted with one or more groups, which may be identical or different, preferably substituted with a group iii) -C(O)O-R3; more preferentially, R2 is a saturated linear C1-C4 or branched C3-C4 hydrocarbon group substituted with a group iii) -C(O)-OR3; and

R3 denotes a radical chosen from: a) a hydrogen atom, and b) a saturated linear C1-C4 or branched C3-C4 alkyl group such as methyl or ethyl.

According to another preferred embodiment, the compounds of formula (I) and the tautomer (I’) are chosen from the compounds of formula (II) below and also the tautomers thereof of formula (II’) below, the salts thereof, the solvates thereof and the optical isomers thereof, and the racemates thereof, alone or as a mixture:

[Table 1]

In formulae (II) and (II’), R1 and R3 have the same meaning as R1 and R3 in the compounds of formulae (I) and (I’), and X denotes an alkylene radical -(CH2)n- with n being an integer ranging inclusively from 1 to 10, preferably ranging from 1 to 6, more preferably ranging from 1 to 4, such as 1 , preferably R3 represents a hydrogen atom.

Among the compounds of formula (I), the following compounds are preferably used, and the tautomer (I¹) thereof or salts thereof, optical isomers, racemates, and/or solvates thereof, such as hydrates thereof, alone or as a mixture: [Table 2]

Among these compounds, the following compounds are more particularly preferred: [Table 3]

More preferably, among these compounds, the following compounds are more particularly preferred:

[Table 4]

Even more preferably, among these compounds, the following compounds are more particularly preferred:

[Table 5]

In the most preferred embodiment, the compound according to the present invention is the following: All the above compounds can be obtained by a chemical process known to a person skilled in the art, from commercially available reagents.

The thiopyridinone compound (1) may be prepared in accordance with the process described, for example, in document EP-A-3390363 or WO 2017/102349.

The thiopyridinone compound (1) may be an active ingredient or an active compound in cosmetic or dermatological products. The term "active" ingredient or compound used here denotes an ingredient or a compound which has an active cosmetic or dermatological property, such as antioxidant, whitening, UV-screening and anti-bacterial effects. The thiopyridinone compound (1) used in the present invention can function as a depigmenting, decolorizing or whitening agent, and thus the composition according to the present invention can be used as a whitening product or as a cosmetic composition for whitening a keratin material.

The thiopyridinone compound (1) can be used as an agent for depigmenting, decolorizing or whitening the skin, body hair, eyelashes or hair, and also the lips and/or nails, and preferably the skin, in particular to remove pigmentation spots or age spots, and/or as an anti-tanning agent.

According to a preferred embodiment, the amount of the thiopyridinone compound(s) (1) in the composition according to the present invention is greater than or equal to 0.01% by weight, more preferentially greater than or equal to 0.05% by weight, and better still greater than or equal to 0.1 % by weight, relative to the total weight of the composition.

According to another preferred embodiment, the amount of the thiopyridinone compound(s)

(1) in the composition according to the present invention is less than or equal to 10% by weight, more preferentially less than or equal to 5% by weight, and better still less than or equal to 3% by weight, relative to the total weight of the composition.

Preferably, the amount of the thiopyridinone compound(s) (1) in the composition according to the present invention is greater than or equal to 0.01 % and less than or equal to 10% by weight, more preferentially greater than or equal to 0.05% and less than or equal to 5% by weight, better still greater than or equal to 0.1% and less than or equal to 3% by weight, relative to the total weight of the composition.

(2) Saturated C16-C22 fatty alcohol(s)

The composition according to the invention comprises (2) one or more saturated C16-C22 fatty alcohols.

The term “saturated fatty alcohol" means any alcohol comprising a linear saturated (containing no covalent double or triple bonds) hydrocarbon chain, in particular a linear alkyl radical, said chain comprising between 16 and 22 carbon atoms and a hydroxyl function.

For the purposes of the invention, the term “hydrocarbon chain" means an organic group predominantly or even exclusively formed from hydrogen atoms and carbon atoms. In particular, this chain is free of silicon atoms and is thus not silicone-based.

The saturated fatty alcohol (2) present in the composition in accordance with the invention comprises between 16 and 22 carbon atoms, preferably between 16 and 18 carbon atoms.

The saturated fatty alcohol (2) present in the composition in accordance with the invention is solid at ambient temperature (20°C +/- 5°C) and advantageously has an -OH function at the end of the chain. The saturated fatty alcohol (2) that is useful in the context of the present invention may notably be chosen from cetyl alcohol, stearyl alcohol, behenyl alcohol and mixtures thereof, and preferably from cetyl alcohol, stearyl alcohol, and mixtures thereof.

Particularly preferably, use will be made of a saturated fatty alcohol (2) chosen from cetyl alcohol, stearyl alcohol, and mixtures thereof such as cetylstearyl alcohol (also known as cetearyl alcohol).

More preferentially, the composition according to the invention comprises a mixture of Ci6 and Cis fatty alcohols (2).

More preferably, the composition comprises a mixture of at least two saturated Ci6 and Cis fatty alcohols, respectively, preferably in a Ci6 fatty alcohol(s)/Cis fatty alcohol(s) mass ratio ranging from 20/80 to 80/20 and advantageously in a Ci6 fatty alcohol(s)/Cis fatty alcohol(s) mass ratio equal to 50/50.

In particular, the composition comprises at least a mixture of cetyl (Cie) and stearyl (Cis) alcohols, also known as cetylstearyl alcohol.

According to a preferred embodiment, the amount of the C16-C22 fatty alcohol(s) (2) in the composition according to the present invention is greater than or equal to 1 % and less than or equal to 10% by weight, more preferentially greater than or equal to 2% and less than or equal to 8% by weight, and better still greater than or equal to 2.5% and less than or equal to 7% by weight, relative to the total weight of the composition.

(3) Anionic surfactant(s) comprising at least one C16-C22 hydrocarbon chain

The composition according to the invention comprises (3) one or more anionic surfactant(s) comprising at least one C16-C22 hydrocarbon chain.

The anionic surfactant (3) that is useful in the context of the invention comprises at least one C16-C22 and preferably C16-C18 hydrocarbon chain. This chain may be linear, saturated (not containing any double or triple covalent bonds) or unsaturated (possibly containing one or more double and/or triple covalent bonds).

Preferably, the anionic surfactant (3) that is useful in the context of the invention comprises only one saturated or unsaturated linear hydrocarbon chain.

In particular, the anionic surfactant (3) contains only one C16-C22 and preferably C16-C18 hydrocarbon chain.

According to a particular embodiment of the invention, the anionic surfactant (3) is chosen from surfactants also comprising at least one sulfonate function, notably as defined hereinbelow in formula (III), acyl glutamates, and mixtures thereof.

According to a particular embodiment of the invention, the anionic surfactant (3) is chosen from surfactants comprising at least one sulfonate function, and mixtures thereof.

More particularly, the anionic surfactant (3) may be chosen from the surfactants of general formula (III):

R-C(O)-Y-(CH₂)n-SO₃M (III) formula (III) wherein:

- R represents a saturated linear or branched C16-C22 alkyl group;

- Y represents -O- or -NR7- with R7 representing a linear or branched C1-C3 alkyl group;

- M is chosen from the group formed by a hydrogen atom, alkali metal or alkaline-earth metal cations, ammonium salts and organic amines;

- n is an integer ranging from 1 to 3; and mixtures thereof. According to a particular embodiment of the invention, the anionic surfactant (3) is chosen from (Ci6-C22)alkylsulfonate salts, (Ci6-C22)alkylamidesulfonate salts, (Ci6- C22)alkylarylsulfonate salts, (Ci6-C22)alkylsulfoacetate salts, N-(Ci6-C22)acyl-N-(Ci- Ce)alkyltaurate salts, (Ci6-C22)acylisethionate salts, (Ci6-C22)alkylsulfolaurate salts, and mixtures thereof.

Preferentially, the anionic surfactant (3) is chosen from:

- acylisethionates, the linear or branched acyl group comprising from 16 to 22 carbon atoms, preferably from 16 to 18 carbon atoms;

- N-acyl-N-alkyltaurates, the linear or branched acyl group comprising from 16 to 22 carbon atoms, preferably from 16 to 18 carbon atoms, and the linear or branched alkyl group comprising from 1 to 6 carbon atoms, or the cyclic alkyl group comprising from 3 to 6 carbon atoms; preferably, the alkyl group is a methyl; and

- mixtures thereof; in particular in the form of alkali metal or alkaline-earth metal, ammonium or amino alcohol salts.

As N-acyl-N-alkyltaurates, mention may be made of sodium palmitoyl methyltaurate sold under the name Nikkol PMT® by Nikkol; the sodium salt of N-stearoyl N-methyltaurate (sodium N-stearoyl-N-methyltaurate) sold under the name Nikkol SMT by Nikko.

Preferably, the anionic surfactant (3) is sodium N-stearoyl-N-methyltaurate.

According to another particular embodiment of the invention, the anionic surfactant (3) is chosen from acyl glutamates wherein the acyl group comprises from 16 to 18 carbon atoms.

Examples of acyl glutamates that may notably be mentioned include palmitoyl glutamic acid, stearoyl glutamic acid, behenoyl glutamic acid, olivoyl glutamic acid, and the salts of these acids, notably the alkali metal salts such as the Na, Li or K and preferably Na or K salts, the alkaline-earth metal salts such as the Mg salts or the ammonium salts of said acids.

Mention may be made, for example, of the compounds having the INCI name sodium stearoyl glutamate, sodium olivoyl glutamate, and mixtures thereof.

As acylglutamic acid salts, mention may also be made of sodium stearoyl glutamate, such as the product sold under the name Amisoft® HS 11 PF by Ajinomoto and disodium stearoyl glutamate, such as the product sold under the reference Amisoft® HS-21 P by Ajinomoto.

According to another embodiment of the invention, a composition may comprise a mixture of at least one anionic surfactant (3) comprising at least one sulfonate function, notably of formula (III) as detailed above, and at least one anionic surfactant (3) comprising at least one glutamate function, notably as defined above.

According to a preferred embodiment, the amount of the surfactant(s) (3) described according to the present invention is greater than or equal to 0.01% and less than or equal to 5% by weight, preferably greater than or equal to 0.05% and less than or equal to 2% by weight, and more preferentially greater than or equal to 0.1 % and less than or equal to 1.5% by weight, relative to the total weight of the composition.

In the compositions in accordance with the invention, the fatty alcohol(s) (2)/anionic surfactant(s) (3) weight ratio may range from 10:1 to 6:4, preferably from 19:2 to 7:3, and even more preferentially from 9:1 to 7:2.

Without wishing to be bound by any theory, it appears that the fatty alcohol(s) (2) and the anionic surfactant(s) (3) including at least one C16-C22 hydrocarbon chain form, with the hydrophilic phase, an alpha crystalline phase, also referred to as alpha gel. This phase may 1 notably be characterized by DSC analysis and by X-ray diffraction at a temperature lower than the melting point of the alpha gel phase.

Thus, the composition in accordance with the invention is capable of forming crystalline lamellar phases.

According to a particular embodiment, the compositions of the invention contain at least one swollen alpha-crystalline phase having a swelling period of greater than 10 nm, preferably greater than 12 nm and even more preferentially greater than or equal to 15 nm. The swelling period is defined as being the sum of the thickness of a bilayer formed by the fatty alcohol(s) (2) and the anionic surfactant(s) (3) and the thickness of the water layer between two leaflets, this unit being repeated several times.

According to a particular embodiment, in a composition according to the invention, the difference between the number of carbon atoms in the hydrocarbon chain of the anionic surfactant(s) (3) and the number of carbon atoms in the fatty alcohol(s) (2) does not differ by more than 5 carbon atoms, and is preferentially less than or equal to 4.

(4) Reducing agent

The composition of the present invention comprises one or more reducing agent(s) (4), preferably one or more inorganic reducing agent(s).

The reducing agent (4), which is preferably inorganic, is more preferentially chosen from the reducing agents of general formula (IV), mesomeric forms thereof, solvates thereof such as hydrates, and mixtures thereof:

[Chem. 6] formula (IV) wherein:

X represents a heteroatom chosen from oxygen, sulfur, preferably oxygen, atoms; m is 0 or 1 ;

M+ is a cation, preferably chosen from alkali metals, alkaline-earth metals and ammonium, more preferentially chosen from alkali metals such as sodium or potassium;

R represents a group chosen from: i) -OH; ii) -O-M’+, with M’+ as previously defined for M+; iii) [Chem. 7] formula iii) wherein:

- p corresponds to an integrator exclusively chosen between 0 and 4, preferably chosen from 0, 1 and 2, more preferably 0 or 2;

- m’ is 0 or 1 , preferably m’ is 1 ;

- X’ is as previously defined for X; preferably, X’ represents an oxygen atom; and - M”+ is as previously defined for M+, and M+, M’+, M”+ are identical or different, preferably identical.

Preferentially, the composition comprises an inorganic reducing agent of formula (IV) wherein:

- X represents a heteroatom chosen from oxygen and sulfur, preferably an oxygen atom,

- m is 0 or 1 ;

- M⁺ is a cation, preferably a sodium or potassium cation;

- R represents a group chosen from: i) -OH; ii) -O-M’⁺, with M’⁺ as previously defined for M⁺; iii) [Chem. 8]

(iii) wherein:

- p is 0 or 2;

- m’ is 0 or 1 ;

- X’ as previously defined for X; preferably, X’ represents an oxygen atom; and

- M+, M’+, M”+ are identical.

More preferentially, the composition comprises an inorganic reducing agent of formula (IV) wherein:

- m is 0 or 1 ;

- M⁺ is a cation, preferably a sodium or potassium cation;

- R represents a group chosen from: i) -OH; ii) -O-M’⁺, with M’⁺ as previously defined for M⁺; iii) [Chem. 9]

(iii) wherein:

- p is 0 or 2;

- m’ is 0 or 1 ;

- X' represents an oxygen atom; and

M⁺, M’⁺, M”⁺ are identical, chosen from sodium or potassium.

According to a particularly preferred embodiment, the composition comprises an inorganic reducing agent of formula (II) wherein:

- X represents a sulfur;

- m is 1 ;

- M⁺ represents sodium or potassium, preferably sodium;

- R represents a group chosen from: i) -OH; ii) -O-M’⁺, with M’⁺ as previously defined for M⁺;

M+, M’+, M”+ are identical.

According to a particular embodiment, the compound of formula (IV) can be in one of its limiting (or mesomeric) forms by electron delocalization, if m = 0 then R-S(O’M⁺)=O R-S(=O)-O’M⁺ and if m = 1 then its limiting mesomeric forms are: R-S(O'M⁺)(=X)_m=O R-S(=O)(=X)_m-O'M⁺ R-S(=O)(X-M⁺)_m=O wherein M⁺, M’⁺, M”⁺ are present to ensure the electronegativity of the molecule of formula (IV).

According to a preferred embodiment, the reducing agent (4), which is preferably inorganic, is chosen from alkali metal bisulfite, alkali metal metabisulfite, alkali metal sulfite, alkali metal thiosulfate, alkali metal sulfate, alkali metal tetrathionate, more preferentially chosen from sodium bisulfate, sodium metabisulfite, sodium sulfite, sodium thiosulfate, sodium sulfate, potassium metabisulfite, potassium sulfite, potassium thiosulfate, potassium sulfate, potassium tetrathionate, or mixtures thereof.

More preferentially, the reducing agent (4) can be chosen from sodium bisulfite, sodium metabisulfite, sodium sulfite, sodium thiosulfate or sodium sulfate, or mixtures thereof, better still the reducing agent (4) is sodium thiosulfate.

In a particularly preferred embodiment, the reducing agent (4) is alkali metal thiosulfate such as sodium thiosulfate.

The composition of the present invention preferably comprises a reducing agent (4) in an amount of greater than or equal to 0.05% by weight, more preferentially greater than or equal to 0.1% by weight, better still greater than or equal to 0.2% by weight and even better still greater than or equal to 0.3% by weight, relative to the total weight of the composition.

According to a preferred embodiment, the composition of the present invention comprises a reducing agent (4) in an amount of less than or equal to 2.0% by weight, preferably of less than or equal to 1.0% by weight, more preferentially less than or equal to 0.7% by weight, relative to the total weight of the composition.

According to another preferred embodiment, the amount of reducing agent (4) in the composition according to the present invention is greater than or equal to 0.05% and less than or equal to 2% by weight, preferably greater than or equal to 0.1% and less than or equal to 1% by weight, and more preferentially greater than or equal to 0.3% and less than or equal to 0.7% by weight, relative to the total weight of the composition.

According to another particularly preferred embodiment, the amount of inorganic reducing agent such as sodium thiosulfate is greater than or equal to 0.05% and less than or equal to 2% by weight, preferably greater than or equal to 0.1% and less than or equal to 1% by weight, and more preferentially greater than or equal to 0.3% and less than or equal to 0.7% by weight, relative to the total weight of the composition.

(5) Chelating agent

The composition according to the present invention comprises (5) one or more chelating agent(s) other than (4). Two or more chelating agents may be used in combination. Thus, a single type of chelating agent or a combination of various types of chelating agents can be used.

The chelating agent (5) other than (4) may be an organic or inorganic chelating agent, the chelating agent (5) other than (4) preferably being chosen from organic chelating agents. The chelating agent (5) may be chosen from carboxylic acids, preferably aminocarboxylic acids, hydroxycarboxylic acids (hydroxylated acids), phosphonic acids, preferably aminophosphonic acids, polyphosphoric acids, preferably linear polyphosphoric acids, and salts thereof. The salts may be, for example, alkali metal salts, alkaline-earth metal salts or ammonium and substituted-ammonium salts.

As chelating agent (5), mention may be made of:

(i) aminocarboxylic acids and salts thereof, such as the following compounds: ethylenediaminedisuccinic acid (EDDS), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA) and salts thereof, such as EDTA 2Na and EDTA 4Na, ethylenediamine-N,N'-diglutaric acid (EDDG), glycinamide-N,N'-disuccinic acid (GADS), 2-hydroxypropylenediamine-N,N'-disuccinic acid (HPDDS), ethylenediamine- N,N'-bis(ortho-hydroxyphenylacetic) acid (EDDHA), N,N'-bis(2- hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED), nitrilotriacetic acid (NTA), methylglycine diacetic acid (MGDA), N-2-hydroxyethyl-N,N-diacetic acid and glyceryl iminodiacetic acid (as described in documents EP-A-317 542 and EP-A-399 133), iminodiacetic acid-N-2-hydroxypropyl sulfonic acid and aspartic acid-N-carboxymethy-N-2- hydroxypropyl-3-sulfonic acid (as described in EP-A-516 102), beta-alanine-N,N”-diacetic acid, aspartic acid-N,N’-diacetic acid and aspartic acid-N-monoacetic acid (described in EP- A-509 382), chelating agents based on iminodisuccinic acid (IDSA) (as described in EP-A- 509,382), ethanoldiglycinic acid, and phosphonobutanetricarboxylic acid, such as the compound sold by Bayer under the reference Bayhibit AM, tetrasodium glutamate diacetate (GLDA) such as Dissolvine GL38 or 45S or GL-47-S from Akzo Nobel;

(ii) hydroxycarboxylic acids and salts thereof, such as citric acid and salts thereof, for example sodium citrate, in particular disodium citrate;

(iii) chelating agents based on mono- or polyphosphonic acid and salts thereof, such as the compounds having the following INCI name: diethylenetriaminepenta(methylenephosphonic) acid (DTPMP), ethane-1-hydroxy-1 ,1 ,2- triphosphonic acid (E1 HTP), ethane-2-hydroxy-1 ,1 ,2-triphosphonic acid (E2HTP), ethane- 1-hydroxy-1 ,1-diphosphonic acid (EHDP), ethane-1 ,1 ,2-triphosphonic acid (ETP), ethylenediaminetetramethylenephosphonic acid (EDTMP) and hydroxyethane- 1 ,1- diphosphonic acid (HEDP), salts thereof and derivatives thereof, and

(iv) chelating agents based on polyphosphoric acid and salts thereof, such as the compounds having the following INCI name: sodium tripolyphosphate (STP), tetrasodium diphosphate, hexametaphosphoric acid, sodium metaphosphate, phytic acid, salts thereof and derivatives thereof, and mixtures thereof.

According to a preferred embodiment, the chelating agent(s) is(are) chosen from aminocarboxylic acids and salts thereof, hydroxycarboxylic acids and salts thereof, and more particularly from aminocarboxylic acids.

Preferably, the chelating agent(s) (5) is (are) chosen from EDDS and salts thereof, EDTA and salts thereof, citric acid and salts thereof, N,N-bis(carboxymethyl)-L-glutamic acid and salts thereof, such as tetrasodium glutamate diacetate, metaphosphates (e.g. sodium metaphosphate), and mixtures thereof; more preferentially, the chelating agent (5) is chosen from EDDS, salts thereof and mixtures thereof.

The amount of the chelating agent(s) (5) other than (4) in the composition according to the present invention may be greater than or equal to 0.01% by weight, preferably greater than or equal to 0.05% by weight, and more preferably greater than or equal to 0.1 % by weight, even better still greater than or equal to 0.2% by weight, relative to the total weight of the composition. Moreover, the amount of the chelating agent(s) (5) other than (4) in the composition according to the present invention may be less than or equal to 3% by weight, preferably less than or equal to 2% by weight, and more preferentially less than or equal to 1 % by weight, even better still less than or equal to 0.4% by weight, relative to the total weight of the composition.

The amount of the chelating agent(s) (5) other than (4) in the composition according to the present invention may be greater than or equal to 0.01 % and less than or equal to 3% by weight, preferably greater than or equal to 0.05% and less than or equal to 2% by weight, more preferentially greater than or equal to 0.1% and less than or equal to 1 % by weight, even better still greater than or equal to 0.2% and less than or equal to 0.4% by weight, relative to the total weight of the composition.

Oily phase

Preferably, the composition according to the invention comprises an oily phase.

The proportion of the oily phase of the emulsion may range, for example, from 1 % to 50% by weight, preferably from 3% to 35% by weight, better still from 5% to 30% by weight, and even better still from 6% to 20% by weight relative to the total weight of the composition.

This amount of oily phase takes into account the content of hydrophobic ingredients required according to the invention and as defined previously.

In addition to the ingredients required according to the invention and detailed above, the oily phase may comprise one or more additional fatty substances notably chosen from waxes, pasty compounds and lipophilic polymers.

For the purposes of the present invention, the term “wax” means a lipophilic compound that is solid at ambient temperature (25°C), with a solid/liquid reversible change of state.

According to a preferred embodiment, the oil(s) is (are) chosen from linear alkanes comprising more than 8 carbon atoms, liquid fatty alcohols at room temperature with a branched and optionally unsaturated carbon chain having from 12 to 26 carbon atoms, synthetic esters and mixtures thereof, more preferably chosen from C15-C19 alkane, octyldodecanol and oleyl erucate.

Aqueous phase

Preferably, the composition according to the invention comprises an aqueous phase. This aqueous phase comprises at least water optionally as a mixture with one or more water- soluble solvents.

The amount of aqueous phase may range from 50% to 99% by weight, preferably from 65% to 97% by weight and more preferentially from 70% to 95% relative to the total weight of the composition. The amount of water may represent all or some of the aqueous phase and it is generally at least 20% by weight, preferably at least 30% by weight, relative to the total weight of the composition.

According to a particular embodiment, the aqueous phase contains at least one polyol.

Advantageously, the composition according to the invention is in the form of an oil-in-water or water-in-oil, preferably oil-in-water, emulsion.

Additional active agent(s)

The composition may also comprise at least one additional active agent. Active agents that may be mentioned include, for example, moisturizers, depigmenting agents, desquamating agents, anti-aging agents, mattifying agents; cicatrizing agents; preserving agents; UV-screening agents, and mixtures thereof.

Preferably, the composition according to the invention comprises from 0.01 % to 20% by total weight of at least one active agent, preferably from 0.05% to 15% by weight, and preferentially from 0.1% to 10% by weight of at least one active agent relative to the total weight of the composition.

The compositions of the invention may contain one or more adjuvants commonly used in the cosmetic and dermatological fields, lipophilic gelling and/or thickening agents; emollients; sequestrants; antioxidants; fillers; free-radical scavengers; essential oils; fragrances; film-forming agents; dyes; pearlescent agents, pigments such as iron oxide, and mixtures thereof. The total amounts of these various adjuvants are those conventionally used in the fields under consideration. In particular, these amounts vary according to the desired aim and may range, for example from 0.01 % to 20% and preferably from 0.1% to 10% by weight relative to the total weight of the composition.

Needless to say, a person skilled in the art will take care to select the optional adjuvant(s) added to the composition according to the invention such that the advantageous properties intrinsically associated with the composition in accordance with the invention are not, or are not substantially, adversely affected by the envisaged addition.

According to a preferred embodiment, the composition according to the invention does not comprise any di-t-butyl pentaerythrityl tetrahydroxycinnamate

The composition used according to the invention may be in any presentation form normally used in the cosmetics field.

It may be more or less fluid and may have the appearance of a gel, a white or colored cream, an ointment, a milk, a lotion, a serum or a paste.

According to a particular embodiment, the compositions according to the invention are not solid.

In particular, the compositions according to the invention are not solid and are not in stick form.

According to a particular embodiment, the compositions according to the invention are in a non-solid presentation form, ranging from a serum texture to a creamy texture which can be stored in a jar.

Advantageously, the viscosity of a composition according to the invention ranges from 100 cP (centipoises), corresponding to 0.1 Pa.s (Pascal. second) to 20 040 cP, corresponding to 20.04 Pa.s measured at 25°C.

The viscosity of a composition according to the invention may be measured by any method known to a person skilled in the art, and in particular by applying a conventional method. For example, the measurement may be performed at 25°C using a Contraves TV, Rheomat RM 180 or Rheomat RM 100 Plus viscometer, equipped for example with a spindle rotating at 200 rpm. A person skilled in the art can choose the spindle used to measure the viscosity, for example from spindles M1 , M2 or M4, according to their general knowledge, so as to be able to perform the measurement.

In particular, the composition according to the invention is intended for application to the skin. This may be the skin of the face and/or of the body, such as the face and/or the neck and/or the hands and/or the neckline. The composition according to the invention may comprise any constituent usually employed in the envisaged topical application and administration.

Advantageously, as already specified above, a composition according to the invention is not intended to be rinsed off after application and in this respect is therefore different than a “cleansing” and/or “makeup-removing” composition.

A subject of the composition according to the invention is also the cosmetic use of a composition according to the invention for caring for keratin materials, in particular for caring for bodily and/or facial skin.

A subject of the present invention is also a process for treating keratin materials, notably human keratin materials such as the skin, wherein a composition according to the invention is applied to said keratin materials.

More particularly, the treatment process, preferably a whitening process, is a process for keratin materials such as the skin, in particular bodily and/or facial skin; said process is non- therapeutic, preferably a care process, wherein a composition according to the invention is applied to said keratin materials.

The cosmetic use or process of the invention is performed by topically administering a composition according to the invention.

Topical administration is constituted of the external application of the cosmetic composition to the skin according to the usual application techniques. Generally, this application may be made directly by a finger, or using a woven or non-woven support on which an adjusted amount of said composition has been deposited beforehand.

The composition in accordance with the invention may be obtained in the usual manner by a person skilled in the art.

The examples that follow will allow the invention to be understood more clearly, without, however, being limiting in nature. The starting materials are referred to by their chemical or INCI name.

Examples

Materials and methods

In the examples below, the compounds are identified by their INCI name:

Cetearyl Alcohol is sold under the name Cetoestearyl Alcohol 50/50 by Industria Quimica del Centro;

Sodium Methyl Stearyl Taurate is sold under the name Nikkol SMT by Nikko;

Trisodium Ethylenediamine Disuccinate is a product sold under the name Natrlquest E30 by Innospec Active Chemicals;

Sodium Thiosulfate is a product sold under the name Pure Sodium Thiosulfate Pentahydrate by Merck;

2-Mercaptonicotinoyl Glycine is a product sold under the name Mexoryl SED by Noveal.

Compositions

In the examples that follow, all the amounts are given as mass percentages of active material (AM) relative to the total weight of the composition (unless otherwise mentioned).

The compositions A and B were prepared from the ingredients of which the contents are indicated in the table below (% active material):

[Table 7]

Process for producing the compositions a) In a rotor stator, phase A is heated with stirring (paddles 60 rpm; turbine 0 rpm) to 70°C, then the turbine is turned on (3500 rpm) for 10 minutes. b) Phase B is separately heated to 72°C with magnetic stirring. c) Phase B is added to phase A with stirring (paddles: 60 rpm, turbine: 800 rpm) then the mixture is stirred for 10 minutes. d) Phase C is added and then the mixture is cooled. e) When the mixture has reached 40°C, phase D is added and then at 30°C phase E is added followed by phase F (homogenized beforehand with a bar magnet at ambient temperature). f) Phase G is added and the composition is cooled to 25°C.

Stability measurement protocol

The compositions are tested for their stability after 24h at 25°C and after two months of storage at 4°C, 25°C and 45°C.

The properties evaluated are:

- the pH of the composition, measured using a pH-meter; - the viscosity of the composition, measured with a viscometer, for example a Lamy Rheology Rheomat RM 100 Plus (equipped with a thermostatic bath), according to the CID- 012-02 method, notably for 10 min;

- the microscopic appearance evaluated by observation of the composition under a light microscope in polarized and non-polarized light, between slide and coverslip, at *10 magnification;

- the color and odor of the composition.

Evaluation of the abovementioned properties is always performed at 25°C, regardless of whether or not the compositions to be tested have been exposed to prolonged storage conditions and/or at temperatures other than 25°C.

A composition is considered to remain stable when its properties, after two months of storage at 4°C, 25°C and 45°C, remain close to those characterized at 24h at 25°C.

In particular, if the composition remains smooth and homogeneous, with no macroscopic destabilization phenomenon (appearance, color, odor) and with no significant change in pH or viscosity, it is considered to be stable.

A macroscopic destabilization phenomenon of the composition may be manifested in the appearance of creaming, coalescence, sedimentation and/or flocculation, the formation of a film at the surface, and/or mottling.

Protocol for measuring the photostability

The compositions are analyzed to evaluate the photostability of 2-Mercaptonicotinoyl glycine (compound 20) during exposure of the compositions to UV radiation.

Each of the compositions A and B were applied independently to an inert support. The supports thus covered were exposed to UV radiation of 5 J/cm² for approximately 1 hour. The exposed compositions were then diluted in a solvent (organic solvent) and the solutions were analyzed by HPLC or UPLC chromatographic methods.

The amount of compound 20 of formula (I) in each of the compositions was measured by HPLC-UV assay at t1 and t2, as indicated below: t1 : After the preparation of the composition; t2: After exposure of the compositions to UV radiation.

The details of the HPLC-UV assays are as follows:

Instruments/Reagents-:

[Table 8]

Conditions:

[Table 9]

The amount of compound 20 of formula (I) contained in the compositions A and B before (t1) and after exposure to UV radiation was determined by HPLC-UV and the difference in amount of compound 20 between t1 and t2 was calculated.

Results: The amounts (%) of compound 20 of formula (I) remaining after exposure of the compositions A and B to UV radiation are given in the table below:

[Table 10]

The results obtained show that compound 20 remains stable under exposure to UV radiation in the composition A according to the invention, unlike the composition B which does not comprise sodium thiosulfate.

It follows therefrom that the composition A according to the invention allows a better photostability of compound 20 in this particular lamellar architecture. Furthermore, the composition according to the invention shows good physicochemical stability. The macroscopic appearance of the composition A according to the invention does not change after storage for 2 months at ambient temperature, 45°C and 4°C.

Claims

1. A composition, notably a cosmetic composition, comprising:

(1) (r) wherein Ri denotes a radical chosen from a) a hydrogen atom, and b) a saturated linear C1-C10 or branched C3-C10 alkyl group optionally substituted with one or more groups, which may be identical or different, chosen from i) -O-R3, and ii) -S-R3, and R2 denotes a radical chosen from a) a hydrogen atom, b) a saturated linear C1-C12 or branched C3-C12 or cyclic C3-C8 hydrocarbon group optionally substituted with one or more groups, which may be identical or different, chosen from i) -O-R3, ii) -S-R3, Hi) - C(O)-O-R3, and iv) a C5-C12 aryl group optionally substituted with one or more hydroxyls and/or with one or more Ci-Cs alkoxy radicals, and c) a C5-C12 aryl group optionally substituted with one or more hydroxyls and/or with one or more Ci-Cs alkoxy radicals, wherein R3 denotes a radical chosen from a) a hydrogen atom, and b) a saturated linear C1-C10 or branched C3-C10 alkyl group;

(2) one or more saturated C16-C22 fatty alcohol(s);

(4) one or more, preferably inorganic, reducing agent(s) and

(5) one or more chelating agent(s) other than (4).

2. The composition as claimed in claim 1 , wherein: R1 of formulae (I) and (I’) represents a hydrogen atom; or R1 of formulae (I) and (I’) represents a linear (C1-C10) or branched (C3-C10) alkyl group, in particular a linear (Ci-Ce) or branched (Cs-Ce) alkyl group, such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably ethyl, in particular, said alkyl group of R1 not being substituted.

3. The composition as claimed in claim 1 or 2, wherein: R2 of formulae (I) and (I’) represents a hydrogen atom; or R2 of formulae (I) and (I’) represents a linear (Ci-C ) or branched (C3-C10) alkyl group, in particular a linear (Ci-Ce) or branched (Ca-Ce) alkyl group, such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably methyl or ethyl; said alkyl group of R2 not being substituted.

4. The composition as claimed in claim 1 or 2, wherein: R2 of formulae (I) and (I’) represents a linear (C1-C10) alkyl group or a branched (C3-C10) alkyl group, in particular a linear (Ci-Ce) alkyl group or a branched (Cs-Ce) alkyl group, such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably methyl or ethyl; said alkyl group being substituted with one or more groups chosen from i), ii), iii) and iv) as defined above, preferably said alkyl group being substituted with one or two groups chosen from i), ii) and iii), more preferably by one or two groups chosen from i) and iii), even better substituted with a group iii) such as carboxy.

5. The composition as claimed in claim 1 or 2, wherein: R2 of formulae (I) and (I’) represents a (Cs-Cs) cycloalkyl group, preferably a (C5-C7) cycloalkyl group such as cyclohexyl; or R2 of formulae (I) and (I’) represents a C5-C12 aryl group optionally substituted with one or more hydroxyls and/or with one or more Ci-Cs alkoxy radicals, preferably a phenyl group, in particular which is not substituted.

6. The composition as claimed in any one of claims 1 to 5, wherein: R3 of formulae (I) and (I’) represents a hydrogen atom, or R3 of formulae (I) and (I’) represents a saturated linear C1-C10 or branched C3-C10 alkyl group; in particular a linear (Ci-Ce) alkyl group or a branched (Cs-Ce) alkyl group, preferably a (C1-C4) alkyl group such as a methyl group.

7. The composition as claimed in any one of claims 1 to 6, wherein: R1 of formulae (I) and (I¹) represents a radical chosen from a) a hydrogen atom, and b) a saturated linear Ci-Ce or branched C3-C6 alkyl group optionally substituted with one or more groups, which may be identical or different, chosen from i) -O-R3, and ii) -S- R3, preferably optionally substituted with one or more groups i); R2 of formulae (I) and (I¹) represents a radical chosen from a) a hydrogen atom and b) a saturated linear C1- C10 or branched C3-C10 or cyclic C3-C8, such as Cs-Ce, hydrocarbon group optionally substituted with one or more groups, which may be identical or different, chosen from i) -O-R3, ii) -S-R3, iii) -C(O)-O-R3, and iv) a phenyl group optionally substituted with one or more hydroxyls and/or with one or more C1-C4 alkoxy radicals such as methoxy, preferably substituted with one or more groups chosen from i) and iii), preferably iii) such as carboxy; and R3 of formulae (I) and (I¹) represents a radical chosen from a) a hydrogen atom, and b) a saturated linear Ci-Ce or branched C3-C6 alkyl group; preferentially, the compounds of formula (I) and the tautomer (I¹), salts thereof, solvates thereof, such as hydrates, optical isomers thereof, racemates thereof, and mixtures thereof, have the following meanings: R1 of formulae (I) and (I¹) represents a radical chosen from: a) a hydrogen atom, and b) a saturated linear C1-C4 or branched C3-C4 alkyl group optionally substituted with one or more groups, which may be identical or different, chosen from i) -OR3, more preferably unsubstituted; R2 of formulae (I) and (I¹) represents a radical chosen from a) a hydrogen atom, and b) a saturated linear C1-C10 or branched C3-C10 or cyclic C3-C8, such as Cs-Ce, hydrocarbon group optionally substituted with one or more groups, which may be identical or different, chosen from i) -O-R3, iii) -C(O)-O-R3, and iv) a C5-C12 aryl group optionally substituted with one or more hydroxyls and/or with one or more C1-C4 alkoxy radicals; and R3 of formulae (I) and (I’) represents a radical chosen from: a) a hydrogen atom; b) a saturated linear C1-C4 or branched C3-C4 alkyl group such as methyl or ethyl.

8. The composition as claimed in any one of claims 1 to 7, wherein: the compound (1) is chosen from the compounds 1 to 24 below, tautomers thereof, salts thereof, solvates thereof, such as hydrates thereof, optical isomers thereof, racemates thereof, and mixtures thereof, in particular the compounds 1 , 2, 4, 6, 7, 9, 11 , 12, 14, 15, 16, 17, 18, 19, 20 or 21 , more particularly 1 , 9, 16, 18, 19, 20 or 21 , preferably 18, 19, 20 or 21 , and more preferably 20:

9. The composition as claimed in any one of the preceding claims, wherein the amount of the thiopyridinone compound(s) (1) is greater than or equal to 0.01 % and less than or equal to 10% by weight, more preferentially greater than or equal to 0.05% and less than or equal to 5% by weight, better still greater than or equal to 0.1 % and less than or equal to 3% by weight, relative to the total weight of the composition.

10. The composition as claimed in any one of the preceding claims, comprising at least one saturated fatty alcohol (2) chosen from: alcohols comprising a linear alkyl radical, said chain comprising between 16 and 22 carbon atoms, preferably between 16 and 18 carbon atoms, and a hydroxyl function; more preferentially, the saturated fatty alcohol(s) (2) present in the composition is(are) solid at ambient temperature (20°C +/- 5°C) and advantageously has an -OH function at the chain end; more preferentially chosen from cetyl alcohol, stearyl alcohol, behenyl alcohol and mixtures thereof, and preferably from cetyl alcohol, stearyl alcohol and mixtures thereof such as cetylstearyl alcohol.

11. The composition as claimed in any one of the preceding claims, wherein the amount of the C16-C22 fatty alcohol(s) (2) is greater than or equal to 1% and less than or equal to 10% by weight, more preferentially greater than or equal to 2% and less than or equal to 8% by weight, and better still greater than or equal to 2.5% and less than or equal to 7% by weight, relative to the total weight of the composition.

12. The composition as claimed in any one of the preceding claims, wherein the anionic surfactant (3) is chosen from anionic surfactants comprising at least one saturated or unsaturated linear C16-C22, preferably C16-C18, hydrocarbon chain, particularly anionic surfactants comprising a single saturated or unsaturated linear hydrocarbon chain; preferably chosen from surfactants additionally comprising at least one sulfonate function, in particular as defined below in formula (III), acyl glutamates, and mixtures thereof;

R-C(O)-Y-(CH₂)n-SO₃M (III) formula (III) wherein:

- R represents a saturated linear or branched C16-C22 alkyl group;

- Y represents -O- or -N(R?)- with R? representing a linear or branched C1-C3 alkyl group;

- n is an integer ranging from 1 to 3; and mixtures thereof; preferentially, the anionic surfactant (3) is chosen from:

- mixtures thereof; in particular in the form of alkali metal or alkaline-earth metal, ammonium or amino alcohol salts; even more preferentially wherein the anionic surfactant (3) is chosen from surfactants comprising at least one sulfonate functional group and mixtures thereof; preferably, the anionic surfactant (3) is N-stearoyl-N-methyltaurate of an alkali metal salt, notably sodium N-stearoyl-N-methyltaurate.

13. The composition as claimed in any one of the preceding claims, wherein the amount of the surfactant(s) (3) is greater than or equal to 0.01% and less than or equal to 5% by weight, preferably greater than or equal to 0.05% and less than or equal to 2% by weight, and more preferentially greater than or equal to 0.1 % and less than or equal to 1 .5% by weight, relative to the total weight of the composition.

14. The composition as claimed in any one of the preceding claims, wherein the reducing agent (4) is chosen from the inorganic reducing agent(s), more preferentially chosen from alkali metal bisulfite, alkali metal metabisulfite, alkali metal sulfite, alkali metal thiosulfate, alkali metal sulfate, alkali metal tetrathionate, better still chosen from sodium bisulfate, sodium metabisulfite, sodium sulfite, sodium thiosulfate, sodium sulfate, potassium metabisulfite, potassium sulfite, potassium thiosulfate, potassium sulfate, potassium tetrathionate, or mixtures thereof, even better still chosen from sodium bisulfite, sodium metabisulfite, sodium sulfite, sodium thiosulfate or sodium sulfate, or mixtures thereof, such that the reducing agent (4) is sodium thiosulfate.

15. The composition as claimed in any one of the preceding claims, wherein the amount of reducing agent (4) is greater than or equal to 0.05% and less than or equal to 2% by weight, preferably greater than or equal to 0.1 % and less than or equal to 1 % by weight, and more preferentially greater than or equal to 0.3% and less than or equal to 0.7% by weight, relative to the total weight of the composition.

16. The composition as claimed in any one of the preceding claims, wherein the chelating agent(s) (5) other than (4) is (are) chosen the organic chelating agent(s), preferably chosen from EDDS and salts thereof, EDTA and salts thereof, citric acid and salts thereof, N,N-bis(carboxymethyl)-L-glutamic acid and salts thereof, such as tetrasodium glutamate diacetate, metaphosphates (e.g. sodium metaphosphate), and mixtures thereof; more preferentially, the chelating agent (5) other than (4) is chosen from EDDS, salts thereof and mixtures thereof.

17. The composition as claimed in any one of the preceding claims, wherein the amount of the chelating agent(s) (5) other than (4) in the composition according to the present invention may be greater than or equal to 0.01% and less than or equal to 3% by weight, preferably greater than or equal to 0.05% and less than or equal to 2% by weight, more preferentially greater than or equal to 0.1 % and less than or equal to 1% by weight, even better still greater than or equal to 0.2% and less than or equal to 0.4% by weight, relative to the total weight of the composition.

18. A process for treating keratin materials, preferably a process for whitening, in particular facial and/or bodily skin, comprising the application of the composition as claimed in any one of claims 1 to 17.

19. The use of a composition as claimed in one of claims 1 to 17, for treating keratin materials, in particular for caring for bodily and/or facial skin.