Patent Application
20080159969
The present invention relates to a novel cosmetic or dermatological composition comprising a combination of mequinol (or 4-hydroxyanisole) and a depigmenting agent that can be used to depigment the skin via topical application. The composition according to the invention may also contain a sunscreen.
Pigmentation of the skin results from the synthesis of melanin in the melanocytes of the dermis by the transformation of tyrosine under the influence of a cupro-protein enzyme, tyrosinase.
A skin depigmenting effect may thus be obtained by using a compound that degrades melanin or a tyrosinase inhibitor the blocks the mechanism of transformation of tyrosine into melanin.
Mequinol, or 4-hydroxyanisole, has been known for a long time as a compound with depigmenting activity (Brun R., Journal of the Society of Cosmetic Chemists (1960), 11, 571-9).
The mode of action of mequinol as a depigmenting agent is to act as a tyrosinase substrate (Riley P., Journal of Pathology (1969), 97(2) 1185-91 and Journal of Pathology (1969), 97(2), 193-206).
Vitamin C or derivatives thereof are usually used as antioxidants at concentrations of less than 0.005% of the entirety of the composition, as illustrated in patent U.S. Pat. No. 6,353,029.
Kojic acid is already known in the prior art as a fungal metabolic agent with antioxidant properties, which causes contact dermatitis when its use is prolonged.
Azelaic acid has been reported in the literature as being effective in the treatment of melasma, but this activity appears to be controversial (Sarkar et al., Dermatology 2002, 205: 249-254).
The Applicant has discovered, surprisingly, that the combination of mequinol and of a depigmenting agent taken from a precise list makes it possible to obtain, by means of a synergistic effect, a depigmenting response that is much more efficient than that obtained with mequinol alone, with substantially lower doses.
These smaller amounts will also make it possible to significantly reduce the harmful side effects (redness and irritation) associated with the use of a depigmenting agent.
The invention therefore relates to a skin depigmenting composition comprising, in a physiologically acceptable medium, mequinol and at least one depigmenting agent chosen from the list consisting of kojic acid and derivatives thereof; azelaic acid and derivatives thereof; dicarboxylic acids; vitamin C and derivatives thereof, arbutin and derivatives thereof, and paracetamol.
In particular, the skin depigmenting composition may comprise, as depigmenting agent, kojic acid, azelaic acid or arbutin.
The term “physiologically acceptable medium” means a medium that is compatible with the skin, mucous membranes and/or the integuments.
The term “depigmenting agent” means any active agent with depigmenting activity on the skin. This activity makes it possible to reduce the already-existing pigmentation of the skin and also to prevent any additional pigmentation greater than the natural pigmentation.
The application of a composition containing the combination according to the invention makes possible to obtain pronounced bleaching of the skin.
The invention also relates to a skin depigmenting composition comprising, in a physiologically acceptable medium, mequinol, at least one depigmenting agent and at least one sunscreen.
The composition according to the invention advantageously comprises between 0.0001% and 20% by weight of mequinol relative to the total weight of the composition and between 0.025% and 20% by weight of depigmenting agent relative to the total weight of the composition, and preferably, respectively, between 0.001% and 10% by weight of mequinol relative to the total weight of the composition and between 0.05% and 10% by weight of depigmenting agent relative to the total weight of the composition.
The composition may also comprise at least one sunscreen in preferential concentrations ranging from 0.001% to 30.00% by weight relative to the total weight of the composition.
Among the sunscreens that may be mentioned as non-limiting examples are physical sunscreens such as titanium dioxide and zinc oxide, and chemical sunscreens such as octocrylene, ethylhexyl methoxy-cinnamate, octyl salicylate, avobenzone, oxybenzone, ecamsule and drometrizole trisiloxane, or mixtures thereof.
In one embodiment variant of the present invention, the composition may comprise several sunscreens, in which case each sunscreen may be added in a concentration ranging from 0.001% to 20% by weight relative to the total weight of the composition.
The compositions according to the invention may also comprise any additive usually used in cosmetics or pharmaceuticals, such as sequestrants, antioxidants, preserving agents, fillers, electrolytes, humectants, dyes, common mineral or organic acids or bases, fragrances, essential oils, cosmetic active agents, moisturizers, vitamins, essential fatty acids, sphingolipids, self-tanning compounds, calmatives and skin-protecting agents. Needless to say, a person skilled in the art will take care to select this or these optional additional compound(s), and/or the amount thereof, such that the advantageous properties of the composition according to the invention are not, or are not substantially, adversely affected.
These additives may be present in the composition in a proportion of from 0.001% to 20% by weight relative to the total weight of the composition.
A subject of the present invention is also a pharmaceutical composition as described above, as medicament.
A subject of the present invention is also a cosmetic composition.
The compositions containing the combination according to the invention may be in any galenical form normally used for topical application, for example in the form of solutions, gels or dispersions of the lotion or serum type, of emulsions of liquid or semi-liquid consistency of the milk type, obtained by dispersing a fatty phase in an aqueous phase (O/W) or conversely (W/O), or of suspensions or emulsions of soft, semi-solid or solid consistency of the cream or gel type, or alternatively of microemulsions, microcapsules, microparticles or vesicular dispersions of ionic and/or nonionic type. These compositions are prepared according to the usual methods.
In a known manner, the cosmetic or dermatological compositions of the invention may contain adjuvants that are common in cosmetics or dermatology, such as emulsifiers, hydrophilic or lipophilic gelling agents, hydrophilic or lipophilic active agents other than titanium oxide and α-hydroxy acids, preserving agents, antioxidants, fragrances, fillers, screening agents and dyestuffs. The amounts of these various adjuvants are those conventionally used in cosmetics and/or dermatology, for example from 0.01% to 20% of the total weight of the composition. Depending on their nature, these adjuvants may be introduced into the fatty phase, into the aqueous phase and/or into the lipid vesicles.
The invention also relates to the use of the composition according to the invention as described above in pharmaceuticals and cosmetics.
The compositions of the invention are particularly suitable for treating and preventing pigmentation disorders. Preferentially, the compositions of the invention are suitable for treating and preventing hyperpigmentation disorders such as melasma, chloasma, lentigo, senile lentigo, vitiligo, freckles, post-inflammatory hyperpigmentation caused by abrasion, a burn, a scar, a dermatitis or a contact allergy; nevi, hyperpigmentations of genetic origin, hyperpigmentations of metabolic or medicinal origin, melanomas or any other pigmentary lesions, especially those induced by photo-induced or chronological ageing of the skin and of the integuments.
More preferentially, the compositions according to the invention are suitable for treating melasma.
The compositions according to the invention also find an application in cosmetics, in particular in protecting against the harmful aspects of sunlight, in particular against pigmentary marks.
The invention also relates to a non-therapeutic cosmetic treatment process for beautifying the skin and/or for enhancing its surface appearance, characterized in that a composition comprising mequinol and at least one depigmenting agent is applied to the skin and/or its integuments.
The formulation examples below illustrate the compositions according to the invention, without, however, limiting its scope. Examples illustrating the depigmenting activity of the various compositions according to the invention are also described.
In the compositions below (Examples 1 to 6), the proportions of the various constituents are expressed as weight percentages relative to the total weight of the composition.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0405280 | May 2004 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/FR05/01211 | 5/13/2005 | WO | 00 | 8/20/2007 |
