Use of amino phenol amide derivatives as depigmentation agents

Details Use of amino phenol amide derivatives as depigmentation agents Use of amino phenol amide derivatives as depigmentation agents

1999-11-10

2002-04-02

Page, Thurman K. (Department: 1615)

Drug, bio-affecting and body treating compositions

Bleach for live hair or skin

C424S061000, C424S070100, C424S401000, C424S404000

Reexamination Certificate

active

06365135

ABSTRACT:

This application is a 371 of PCT/FR98/02562 filed Nov. 27, 1998.
The present invention relates to the use of aminophenol amide derivatives as depigmenting or bleaching agents in a cosmetic and/or dermatological composition, and to a depigmenting and/or bleaching composition containing aminophenol amide derivatives.
The colour of human skin depends on various factors and, in particular, the seasons of the year, race and sex, and it is mainly determined by the nature and concentration of melanin produced by the melanocytes. Melanocytes are specialized cells which synthesize melanin by means of specific organelles, the melanosomes. In addition, at different periods in their life, certain individuals develop darker and/or more coloured blemishes on the skin and more especially on the hands, making the skin non-uniform. These blemishes are also due to a large concentration of melanin in the keratinocytes located at the skin surface.
In the same way, the colour of head hair and body hairs is due to melanin. When head hair or body hairs are dark, certain people wish them to be lighter. This is particularly advantageous for hairs which are less visible when they are light than when they are dark.
The mechanism for the formation of skin pigmentation, and pigmentation of head hair and body hairs, that is to say the formation of melanin, is particularly complex and schematically involves the following main steps:
Tyrosine→Dopa→Dopaquinone→Dopachrome→Melanin
Tyrosinase (monophenol dihydroxyl phenylalanine: oxygen oxidoreductase EC 1.14.18.1) is the essential enzyme involved in this reaction sequence. It especially catalyses the reaction for the conversion of tyrosine into dopa (dihydroxyphenylalanine) by virtue of its hydroxylase activity and the reaction for the conversion of dopa into dopaquinone by virtue of its oxidase activity. This tyrosinase acts only when it is in the mature state, under the action of certain biological factors.
A substance is recognized as being depigmenting if it acts directly on the vitality of the epidermal melanocytes in which melanogenesis takes place and/or if it interferes with one of the steps in the biosynthesis of melanin either by inhibiting one of the enzymes involved in melanogenesis or by becoming intercalated as a structural analogue of one of the chemical compounds in the melanin synthesis chain, whereby this chain may then be blocked and thus ensure depigmentation.
The substances most commonly used as depigmenting agents are, more particularly, hydroquinone and its derivatives, in particular its ethers such as hydroquinone monomethyl ether and monoethyl ether. Although they have a certain level of efficacy, these compounds are unfortunately not free of side effects on account of their toxicity, which can make them difficult or even hazardous to use. This toxicity arises from the fact that they interfere with fundamental mechanisms of melanogenesis, by killing cells which then risk disrupting their biological environment and which consequently force the skin to eliminate them by producing toxins.
Thus, hydroquinone is a compound which is particularly irritant and cytotoxic to melanocytes, and whose total or partial replacement has been envisaged by many authors.
Substances have thus been sought which are not involved in the mechanism of melanogenesis, but which act upstream on tyrosinase by preventing its activation, and are consequently much less toxic. Kojic acid is commonly used as a tyrosinase-activation inhibitor, this acid complexing the copper present in the active site of this enzyme. Unfortunately, this compound can give rise to allergic reactions (“Contact allergy to kojic acid in skin care products”, Nakagawa M. et al., in Contact Dermatitis, Jan. 95, Vol. 42 (1), pp. 9-13). In addition, this compound is unstable in solution, which somewhat complicates the manufacture of the composition.
It is most particularly sought to use harmless topical depigmenting substances which have good efficacy, with a view to treating regional hyperpigmentations caused by melanocyte hyperactivity, such as idiopathic melasmas, occurring during pregnancy (“pregnancy mask” or chloasma) or during oestro-progestative contraception, localized hyper-pigmentations caused by hyperactivity and proliferation of benign melanocytes, such as senile pigmentation marks known as actinic lentigo, accidental hyperpigmentations or depigmentations, possibly due to photosensitization or to post-lesional cicatrization, as well as certain leukodermias, such as vitiligo. For the latter, (in which the cicatrizations can result in a scar which gives the skin a whiter appearance and leukodermias), failing being able to repigment the damaged skin, the regions of residual normal skin are depigmented in order to give the skin as a whole a uniform white complexion.
Thus, there is a need for a novel agent for bleaching human skin, body hairs and/or head hair which acts as effectively as the known agents, but which does not have their drawbacks, i.e. which is non-irritant, non-toxic and/or non-allergenic to the skin and which is stable in a composition.
The Applicant has found, unexpectedly, that certain aminophenol amide derivatives have depigmenting activity, even at low concentrations, without showing any cytotoxicity.
Aminophenol amide compounds are already known, in particular in compositions intended for bleaching the skin. Mention may be made in particular of documents JP-07061905 and JP-07233022. It is also known, in particular from the document J. Biol. Chem. (1979), 254(23), 12185-91, that N-(4-hydroxyphenyl)-L-glutamine interacts with tyrosinase.
However, these compounds would be difficult to obtain on an industrial scale. They differ in their structure from the compounds which are the subject of the present invention. In addition, neither of these documents discloses or suggests the noteworthy efficacy of the compounds used according to the present invention.
A subject of the present invention is thus the use of certain aminophenol amide derivatives of iformula (I) in and/or for the manufacture of a cosmetic and/or dermatological composition for depigmenting and/or bleaching human skin and/or for removing pigmentation marks from the skin and/or for depigmenting body hairs and/or head hair.
These aminophenol amide derivatives correspond to formula (I) below:
in which:
R represents
a hydrogen atom;
a linear, branched or cyclic, saturated or unsaturated C
1
-C
24
alkyl group optionally hydroxylated with one or more hydroxyl functions;
an aryl group, which may or may not be substituted with one or more functions chosen from: —OH; NH
2
; —COOH; —NO
2
; —OR
5
with R
5
=C
1
-C
24
alkyl; —COOR
6
with R
6
=C
1
-C
24
alkyl; —NR
7
R
8
with R
7
=H or C
1
-C
24
alkyl, R
8
=H or C
1
-C
24
alkyl;
a group —COR
9
, R
9
representing a linear, branched or cyclic, saturated or unsaturated C
1
-C
24
alkyl group optionally hydroxylated with one or more hydroxyl functions, an aryl group which may or may not be substituted with one or more functions chosen from —OH, —NH
2
, —COOH, —NO
2
, —OR
5
, —COOR
6
, —NR
7
R
8
in which R
5
, R
6
, R
7
and R
8
have the same definition as above;
R
1
and R
2
, which may be identical or different, represent a group chosen from:
a hydrogen atom;
a linear, branched or cyclic, saturated or unsaturated C
1
-C
24
alkyl group optionally hydroxylated with one or more hydroxyl functions;
an aryl group which may or may not be substituted with one or more functions chosen from —OH, —NH
2
, —COOH, —NO
2
, —OR
5
, —COOR
6
, —NR
7
R
8
, in which R
5
, R
6
, R
7
and R
8
have the same definition as above;
a group chosen from: —OH; —OQ
1
; —COQ
2
; —COOQ
3
; —NQ
4
Q
5
; —CONQ
6
Q
7
; —SQ
8
; —CH
2
OQ
9
; Q
1
, Q
2
, Q
3
, Q
4
, Q
5
, Q
6
, Q
7
, Q
8
and Q
9
being chosen from a hydrogen atom; linear, branched or cyclic, saturated or unsaturated C
1
-C
24
alkyl groups optionally substituted with one or more hydroxyl groups; aryls which may or may not be substituted with one or more functions chosen from: —OH, —NH
2

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