Organic compounds -- part of the class 532-570 series – Organic compounds – Cyclopentanohydrophenanthrene ring system containing
Reexamination Certificate
1999-06-21
2002-07-23
Dees, Jose′ G. (Department: 1616)
Organic compounds -- part of the class 532-570 series
Organic compounds
Cyclopentanohydrophenanthrene ring system containing
C424S062000, C514S182000, C514S485000, C514S488000, C514S534000, C514S538000, C514S596000, C514S598000, C514S724000, C514S727000, C514S731000, C552S544000, C560S029000, C564S052000
Reexamination Certificate
active
06423854
ABSTRACT:
The present invention relates to the use of aminophenol derivatives as depigmenting or bleaching agents in a cosmetic and/or dermatological composition, to a cosmetic and/or dermatological composition comprising these derivatives and to novel aminophenol derivatives.
The colour of the skin depends on different factors and, in particular, the seasons of the year, race and sex, and it is mainly determined by the type 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 at the skin surface.
In the same way, the colour of body hairs and head hair is due to melanin. When hairs or head hair are dark, certain people wish to have them 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 body hairs and head hair, 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. 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 be blocked and ensure the 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 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, January 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 are of good efficacy, in order to treat 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 damage to the 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, 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 aminophenol derivatives have depigmenting activity, even at low concentrations, without showing any cytotoxicity.
Some of these derivatives are already known from U.S. Pat. No. 2,663,730, U.S. Pat. No. 3,933,470, GB-A-1,205,029, DD 107,449 or from A. Etienne et al. “Isocyanurates diméthylés-1.3 et arylés-5 [1,3-dimethyl and 5-aryl isocyanurates]”, Comptes rendus hebdomadaires des séances de l'académie des sciences, Série C: sciences chimiques, Vol. 279, Dec. 2, 1974, pp. 969-972, for example. Other aminophenol derivatives have been discovered by the Applicant.
The subject of the present invention is thus the use of at least one aminophenol derivative of formula (I) below:
in which:
R represents a hydrogen atom or a radical —COR
2
,
wherein R
2
represents a saturated or unsaturated, linear, cyclic or branched, optionally hydroxylated, C
1
to C
30
hydrocarbon or alkoxy radical;
R
1
is a radical of formula (a), (b) or (c) below:
(a) —CO—NR
3
R
4
(b) —CO—O—R
5
(c) —SO
2
—R
5
wherein R
3
represents a hydrogen atom or a linear or branched, saturated or unsaturated, optionally hydroxylated, C
1
to C
6
hydrocarbon radical,
R
4
represents a hydrogen atom or a saturated or unsaturated, linear, cyclic or branched, optionally hydroxylated, C
1
to C
30
hydrocarbon radical,
R
5
represents a saturated or unsaturated, linear, cyclic or branched, optionally hydroxylated, C
1
to C
30
hydrocarbon radical, in a depigmenting and/or bleaching cosmetic composition for human skin, body hairs or head hair.
These compositions have the advantage of being easy to obtain. They can be obtained in particular by reacting an aminophenol with an activated chemical species, such as an imidazolide or an isocyanate when R
1
is a radical of formula (a), a chloroformate when R
1
is a radical of formula (b) or a sulphonyl chloride when R
1
is a radical of formula (c).
The hydrocarbon radicals typically alkyl radicals. Among the linear or branched hydrocarbon radicals having from 1 to 30 carbon atoms, mention may be made advantageously of methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, hexyl, octyl, nonyl, 2-ethylhexyl and dodecyl radicals. Preferably, these radicals have from 1 to 12 carbon atoms. Even more preferably, the hydrocarbon radical generally comprises from 1 to 6 carbon atoms. As lower hydrocarbon radicals, mention may be made of alkyl radicals, for example methyl, ethyl, propyl, isopropyl, tert-butyl and hexyl radicals.
Among the linear alkyl radicals having from 1 to 30 carbon atoms, mention may be made in particular of methyl, ethyl, propyl, octyl, dodecyl, tridecyl, hexadecyl, behenyl, octadecyl, tetracosyl, hexacosyl, octacosyl and myricyl radicals.
Among the branched alkyl radicals having from 1 to 30 carbon atoms, mention may be made in particular of 2-ethylhexyl, 2-butyloctyl and 2-hexyldecyl radicals.
When it is unsaturated, a radical having one or more ethylenic unsaturations is preferred, such as the neryl, 2-nonyl-2-butenyl and 6-(1,3-pentadienyl)-2,4,7-dodecanetrien-9-ynyl rad
Blaise Christian
Philippe Michel
Tuloup Remy
Choi Frank
Dees Jose′ G.
L'Oreal
LandOfFree
Aminophenol derivatives and their use in cosmetics does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Aminophenol derivatives and their use in cosmetics, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Aminophenol derivatives and their use in cosmetics will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2819309