PROCESS FOR DEPIGMENTING KERATIN MATERIALS USING THIOPYRIDINONE COMPOUNDS

Abstract

The invention relates to a cosmetic process for depigmenting, lightening and/or whitening keratin materials, in particular the skin, which comprises the application of a cosmetic composition comprising a compound of formula (I):

##STR00001## or its tautomer form of formula (I′):

##STR00002## in which: R.sub.1 and R.sub.2, which may be identical or different, denote a radical chosen from: a) a hydrogen atom; b) a C.sub.1-C.sub.20 alkyl group optionally interrupted with N, S or O, optionally substituted with one or more group(s) chosen from -—OR.sub.3, —SR.sub.3, —NR.sub.3R.sub.4, —CONHR.sub.3; —COOR.sub.S; and an aryl group optionally substituted with one or more hydroxyls and/or with one or more C.sub.1-C.sub.8 alkoxy radicals; c) a C.sub.1-C.sub.8 alkyl group substituted with a C.sub.5-C.sub.12 aryl radical optionally substituted with one or more hydroxyls and/or with one or more C.sub.1-C.sub.8 alkoxy radicals; d) a phenyl group optionally substituted with one or more hydroxyls and/or with one or more C.sub.1-C.sub.8 alkoxy radicals; R.sub.3 denoting H or a C.sub.1-C.sub.5 alkyl group, R.sub.4 denoting H, a C.sub.1-C.sub.5 hydrocarbon-based group or an acetyl group; it being possible for R.sub.1 and R.sub.2 to form, with the nitrogen atom which bears them, a ring chosen from pyrrolidine, pyrroline, piperidine, piperazine, morpholine, thiomorpholine and azepine.

The invention also relates to the cosmetic use of a compound (I) or (I′) as a whitening, lightening and/or depigmenting agent for keratin materials.

Claims

1. Nontherapeutic cosmetic process for depigmenting, lightening and/or whitening keratin materials, which comprises the application of a cosmetic composition comprising, in a physiologically acceptable medium, at least one compound of formula (I): ##STR00059## or its tautomer form of formula (I′): ##STR00060## in which: R.sub.1 and R.sub.2, which may be identical or different, denote a radical chosen from: a) a hydrogen atom; b) a saturated linear C.sub.1-C.sub.20 or branched C.sub.3-C.sub.20 or unsaturated C.sub.2-C.sub.20 alkyl group, optionally interrupted with one or more heteroatoms chosen from N, S and O, and/or optionally substituted with one or more groups, which may be identical or different, chosen from: i) —OR.sub.3 ii) —SR.sub.3, iii) —NR.sub.3R.sub.4 iv) —CONHR.sub.3 v) —COOR.sub.3; vi) a C.sub.5-C.sub.12 aryl group optionally substituted with one or more hydroxyls and/or with one or more C.sub.1-C.sub.8 alkoxy radicals; c) a saturated C.sub.1-C.sub.8 alkyl group substituted with a C.sub.5-C.sub.12 aryl radical optionally substituted with one or more hydroxyls and/or with one or more C.sub.1-C.sub.8 alkoxy radicals; d) a phenyl group optionally substituted with one or more hydroxyls and/or with one or more C.sub.1-C.sub.8 alkoxy radicals; R.sub.3 denoting a hydrogen atom or a saturated linear C.sub.1-C.sub.5 or branched C.sub.3-C.sub.5 or unsaturated C.sub.2-C.sub.5 hydrocarbon-based group, R.sub.4 denoting a hydrogen atom; a saturated linear C.sub.1-C.sub.5 or branched C.sub.3-C.sub.5 hydrocarbon-based group; or an acetyl group; it being possible for R.sub.1 and R.sub.2 to form, with the nitrogen atom which bears them, a ring chosen from pyrrolidine, pyrroline, piperidine, piperazine, morpholine, thiomorpholine and azepine; and also the salts thereof, the optical isomers thereof and the racemates thereof.

Description

EXAMPLES 1 to 4

Demonstration of the Activity on Constitutive Melanogenesis

[0144] A biological test demonstrated the depigmenting activity of 7 compounds of formula (I) (compounds 2, 7, 12, 16, 19, 21 and 27).

[0145] The modulatory effect of each compound on melanogenesis was measured according to the method described in FR-A-2734825 and also in the article by R. Schmidt, P. Krien and M. Régnier, Anal. Bichem., 235(2), 113-18,1996. This test is carried out on a coculture of keratinocytes and melanocytes.

[0146] For the compounds tested, the following were determined: [0147] the cytotoxicity, by estimating leucine incorporation, [0148] the inhibitory activity on melanin synthesis, by estimating the ratio of thiouracil incorporation to leucine incorporation, relative to 100% of the control (the control corresponds to the test carried out without test compound). The IC50 values (concentration for which 50% of the melanin synthesis is inhibited) were determined.

[0149] The test was also carried out with arbutin, niacinamide and kojic acid, which are known depigmenting compounds.

[0150] The results are collated in the following table:

TABLE-US-00003 Cytotoxicity on Compound coculture IC50 Arbutin Non-cytotoxic Not attained (or greater than 500 μM) Kojic acid 100 μM Not attained (or greater than 500 μM) Niacinamide Non-cytotoxic Not attained [00052] Non-cytotoxic 4.9 μM  [00053] Non-cytotoxic 37 μM [00054] 100 μM 25 μM [00055] Non-cytotoxic 32 μM [00056] Non-cytotoxic 29 μM [00057] Non-cytotoxic 410 μM  [00058] Non-cytotoxic 128 μM 

[0151] Compounds 2, 7, 12, 16, 19, 21 and 27 therefore demonstrate their efficacy in inhibiting melanogenesis and are, moreover, more effective than arbutin, kojic acid and niacinamide.

[0152] Compound 2 is the most effective compound.

EXAMPLE 5

[0153] A depigmenting gel for the skin is prepared, comprising (% by weight):

TABLE-US-00004 Compound 2 2% Carbomer (Carbopol 981 from Lubrizol) 1% preservative qs water qs 100%  .sup. 

[0154] When applied to the skin, the composition makes it possible to fade out brown marks.

[0155] A similar composition is prepared with compound 3 or compound 11 or compound 16.