FR2926720A1 - COSMETIC COMPOSITION FOR BLOCKING SKIN PIGMENTATION INDUCED BY UV RADIATION - Google Patents

Abstract

Topical cosmetic composition, characterized in that it contains, within a cosmetic vehicle: at least one agent blocking the binding of alpha-MSH to the MC-1 receptors; at least one agent blocking the synthesis of ET-1, at least one SCF synthesis inhibiting agent, at least one tyrosinase inhibiting agent.

Description

COSMETIC COMPOSITION FOR BLOCKING SKIN PIGMENTATION INDUCED BY UV RADIATION

The subject of the invention is a topical cosmetic composition intended to block the pigmentation of the skin induced by UV radiation. In a first embodiment, this composition is used in the absence of UVA and UVB filters, on light skin when seeking to minimize the phenomenon of pigmentation. In this case, the composition is intended more particularly for Asian populations. In a second embodiment, the composition further contains UVA and UVB filters and finds at least two indications. The first indication is its use as an anti-bronzer. Again, the relevant market is the Asian market. The second indication corresponds to skin developing hyperpigmentation phenomena in response to the effects of UV rays.

Melanins are the pigments responsible for the coloring of the skin. They are obtained by mixing a variable amount of two kinds of pigments: phaeomelanins and eumelanines. The eumelanines (true melanins) are pigments of black or brown color, totally absorbing the light and thus exerting a real photoprotective power. Phaeomelanins (red melanins) are orange-yellow pigments that have a lower protective effect. The very light red skins (phototype I) mainly contain phaeomelanines. Melanins are made from tyrosine in the presence of tyrosinase in melanocytes, which are located in the basal layer of the epidermis. This is the process of melanogenesis. The synthesis of melanins is more particularly carried out in melanosomes, which are transported to the end of the dendrites of melanocytes and then transferred to the keratinocytes. The presence of melanins on the surface of the skin makes it possible to absorb some of the visible and UV radiation.

In Asian populations, it is traditional to keep the skin as clear as possible. Before we even worry about the impact of UV radiation, we first and foremost try to stop the pigmentation of the skin, that is to say, to inhibit the production of melanin to lighten the complexion. To do this, many hydroquinone-based compositions have been proposed, hydroquinone acting directly on the melanogenesis process by stopping the synthesis of melanin by inhibition of tyrosinase. This molecule has the disadvantage of being poorly tolerated and is responsible for irritation when used in excess. It can also destroy melanocytes, resulting in the formation of white spots totally depigmented and irreversibly.

The Applicant has now developed a new cosmetic composition which differs from the products of the prior art in that it contains elements that stop melanogenesis: - directly by inhibiting the synthesis of melanins, - indirectly by inhibiting the production of mediators by the keratinocytes under the effect of UV radiation, which also take part in the melanogenesis process. It is first of all a-MSH (alpha-melanocyte stimulating hormone) which is a neuropeptide hormone, produced by irradiated keratinocytes and plays a major role in photoinduced pigmentation. Its attachment to MC-1 receptors on the surface of melanocytes induces a proliferation of melanocytes, an increase in their dendricity, but also an increase in tyrosinase activity and an induction of eumelanin production.

It is then endothelin-1 (ET-1) which is a peptide of 21 amino acids with a high vasoconstrictor power. It also acts on its melanocyte receptors (ETA and ETB) thus inducing an increase in proliferation and dendricity of melanocytes, and stimulating melanogenesis.

It is finally the Stem Cell Factor (SCF) which is produced by keratinocytes and binds to its c-kit receptor on the surface of melanocytes. The expression of SCF is increased during UV irradiation, thus inducing the increase in number and dendricity of melanocytes as well as melanogenesis. ET-1 and SCF have also been shown to act synergistically on the activation of melanogenesis.

The invention therefore firstly relates to a cosmetic composition which is characterized in that it contains, within a cosmetic vehicle: at least one agent blocking the binding of α-MSH to the receptors MC-1, at least one agent blocking the synthesis of ET-1, at least one agent inhibiting the synthesis of SCF, at least one tyrosinase inhibiting agent. This composition is more particularly used as an anti-pigmenting agent.

In an advantageous embodiment, the α-MSH-binding blocking agent on MC-1 receptors is biomimetic hexapeptide 2 and / or nonapeptide-1 obtained by chemical synthesis, having an affinity for the receptor. of a-MSH. In practice, these peptides represent between 0.00001 and 1% by weight of the composition, preferably between 0.0001 and 0.0004% by weight.

Similarly, the ET-1 synthesis blocking agent is advantageously a leaf extract of Andrographis paniculata and in practice is between 0.001 and 10%, preferably between 0.01 and 0.1% by weight of the composition.

Likewise, the inhibiting agent for the synthesis of SCF and of tyrosinase synthesis is the same and is advantageously an aqueous extract of an alga called Palmaria palmata, preferably containing between 5 and 50% by weight of dry matter. , the extract representing in practice between 0.01 and 25% by weight of the composition, ideally between 1 and 4% by weight. Moreover, and this is the second aspect of the invention, to the knowledge of the Applicant, no non-pigmenting compositions of the prior art can limit or even stop the tanning or the phenomenon of hyperpigmentation induced by solar radiation. This hyperpigmentation is reflected in particular by the appearance of brown spots designated lentigo seniles.

To solve this problem, the cosmetic composition of the invention also contains at least one UVB and UVA and / or UVA / UVB filter and optionally at least one mineral screen.

In other words, the invention consists in this case in blocking the penetration of most of the UV rays by means of UVA and UVB filters, or mineral screens, and then directly inhibiting (inhibition of tyrosinase stimulation). and indirectly (inhibition of keratinocyte stimulation) the production and expression of melanin triggered by the remaining part of the UV having penetrated through the skin.

By acting on the main factors involved in the process of melanogenesis, the composition of the invention can be used as an anti-bronzer product for skin with little or weakly pigmented, in particular for the Asian market, or as a product intended to fight against photo-induced hyperpigmentation.

Mineral screens and UVB or UVA / UVB filters are intended to limit the penetration of UVB into the skin. Depending on the nature of the filters, 70 to 98% of the radiation will be stopped. The protection of the skin against UVB is characterized by the SPF index. This index corresponds, for a given UVB irradiation, after application of UVB or UVB / UVA filter, to the ratio between the UV dose triggering an erythema on the protected skin and the UV dose triggering erythema on the unprotected skin. For example, an SPF of 20 means that it takes 20 times more UV to trigger an erythema, so is to say that 95% of UVB rays are stopped. An index of 50 means that 98% of UVB rays are stopped. In the invention, the UVB and / or UVA / UVB filter (s) are chosen to give the composition an SPF index of a minimum value of advantageously at least 50.

Those skilled in the art will be able to choose the appropriate components and their proportions to obtain such indices in accordance with the international standards in force (colipa, FDA), in particular the UVB or UVA organic screening agents chosen from the group comprising: para-aminobenzoic acid: PABA, Ethyl PABA, Ethyl Dihydroxypropyl PABA (Amerscreen P sold by Amerchol), Ethylhexyl Dimethyl PABA sold in particular under the name ESCALOL 507, Glyceryl PABA, PEG-25 PABA sold under the name UVINUL P25. salicylic derivatives: Homosalate sold under the name EUSOLEX HMS, Ethylhexyl Salicylate sold under the name NEO HELIOPAN OS, Dipropylene glycol salicylate sold under the name DIPSAL, TEA Salicylate sold under the name NEO HELIOPAN TS - Derivatives of dibenzoylmethane: Butyl Methoxydibenzoylmethane , - Isopropyl Dibenzoylmethane. cinnamic derivatives: Ethylhexyl methoxyciannamate sold in particular under the trade name PARSOL 1789, Isopropyl Methoxy Cinnamate, Isoamyl Methoxy Cinnamate sold under the trade name NEO HELIOPAN E 1000, Cinoxate, DEA Methoxycinnamate, Glyceryl Ethylhexanoate Dimethoxycinnamate.

Derivatives of I-I '-diphenylacrylate: - Octocrylene sold in particular under the trade name UVINUL N539, - Etocrylene sold in particular under the trade name UVINUL N35 benzophenone derivatives: -Benzophenone-1 sold under the trade name UVINUL 400, -Benzophenone -2 sold under the trade name UVINUL D50, -Benzophenone-3 or Oxybenzone sold under the trade name UVINUL M40, -Benzophenone-4 sold under the trade name UVINUL MS40, -Benzophenone-5, -Benzophenone-6 sold under the trade name HELISORB 11, - Benzophenone-8 sold under the trade name SPECTRA-SORB UV-24, - Benzophenone-9 sold under the trade name UNIVUL DS-49, -Benzophenone-12. Benzylidene derivatives camphor: -4-Methylbenzylidene camphor sold under the name EUSOLEX 6300, the benzimidazole derivatives: Phenylbenzimidazole Sulfonic Acid sold in particular under the trade name EUSOLEX 232, Disodium Phenyl Dibenzimidazole Tetra-Sulfonate sells u under the trade name NEO HELIOPAN AP triazine derivatives: - Ethylhexyl triazone sold in particular under the trade name UVINUL T150, - Diethylhexyl Butamido Triazone sold under the trade name UVASORB HEB, - (Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine) Tinosorb S derivatives of benzotriazole: - Drometrizole Trisiloxane sold under the name Silatriazole, - Methylene bis-Benzotriazol Tetramethylbutylphenol sold in solid form under the trade name MIXXIM BB / 100 or in micronized form in aqueous dispersion under the trade name TINOSORB M anthranilic derivatives: - Menthyl anthranilate sold under the trade name NEO HELIOPAN MA imidazoline derivatives: - Ethylhexyl Dimethoxybenzylidene Dioxoimidazoline Propionate.

Derivatives of benzalmalonate: - Polyorganosiloxane containing benzalmalonate functions sold under the trade name PARSOL SLX -Diethylamino Hydroxybenzoyl Hexyl Benzoate (sold under the trade name Uvinul A +) - and mixtures thereof.

The composition of the invention may further comprise nacres, pigments, or even nanopigments (average size of the primary particles: generally between 5 nm and 100 nm, preferably between 10 nm and 50 nm) of coated metal oxides or not, as for example nano-pigments of titanium oxide (amorphous or crystallized in rutile and / or anatase form), iron, zinc, zirconium or cerium and their mixtures which are all UV photoprotective agents well known in itself. Conventional coating agents are, moreover, alumina and / or aluminum stearate.

In practice, these filters represent between 2 and 40% by weight of the composition, preferably between 15 and 30% by weight of the composition.

In all cases, the UVA / UVB filters are advantageously chosen from the group comprising: - Bis-ethylhexyloxyphenol Methoxyphenyl Triazine: Tinosorb S - Methylene bis-Benzotriazol Tetramethylbutylphenol: Tinosorb M The mineral screens will advantageously be chosen from the group: TiO 2 ZnO The cosmetic composition of the invention is generally applied topically.

It may be in any galenical form normally used for topical application to the skin, especially in the form of an oil-in-water or water-in-oil or multiple emulsion, a silicone emulsion, a microemulsion or nanoemulsion. This composition may be more or less fluid and have the appearance among others of a white or colored cream, an ointment, a milk, a lotion, a serum or a gel.

The composition of the invention may contain the usual vehicles in the cosmetic and dermatological fields, such as fats, emulsifiers and coemulsifiers, hydrophilic or lipophilic gelling agents, hydrophilic or lipophilic active agents, preservatives, antioxidants, solvents, perfumes, fillers, hydrophilic and lipophilic filters, dyestuffs, neutralizers, pro-penetrating agents, and polymers.

The invention and the advantages that ensue from it will emerge from the following embodiment, in support of the appended figures. 1: solar lightening cream Purified water qs 100% Ethylhexyl Methoxycinnamate (Parsol MCX) 7.00 Butyl Methoxydibenzoylmethane (Eusolex 9020) 3.00 TiO2 Micronized (MT100 TZ) 5.00 Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine (Tinosorb S) 2.00 Methylene bis-Benzotriazol Tetramethylbutylphenol (Tinosorb M) 4.00 Andrographis paniculata 0.10 Hexapeptide 2 0.0004 Palmaria palmata 1.50 Paraffin Liquid 16.00 Cetostearyl alcohol ethylhexanoate 4.00 Sorbitol sesquioleate 1.00 Stearic acid 3.00 Stearyl alcohol 1.70 Glycerol stearate 1.50 Beeswax 1.00 Triethanolamine 0.88 Acrylic polymer 0.20 Preservative qs Perfume qs 2: Lightening serum Purified water qs 100% Ethoxylated Caprylic / Capric glycerides 6 moles 3.50 Xanthan gum 0.50 Polysorbate 20 1.20 Andrographis paniculata 0.10 Hexapeptide 2 0.002 Palmaria palmata 1.00 Sodium hyaluronate 0.10 Preservative qs Perfume qs 3: Skin cream Purified water qs 100% Corn starch Modified 5.50 Andrographis paniculata 0.10 Nonapeptide-1 0.005 Palmaria palmata 1.20 Isododecane 5.00 Polymer Methyl Methacrylate 1.925 Dicaprylate / Propylene Glycol Dicaprate 1.52 Isodecyl Neopentanoate 1.50 Glycerol Stearate 1.30 Ethoxylated Peg Stearate 100 moles 1.00 Stearic Acid 1.00 Pyridoxine Hcl 0.50 Zinc Gluconate 0.50 Sodium Hydroxide 0.32 Preservative qs Perfume qs15

Claims (6)

1 / topical cosmetic composition, characterized in that it contains, within a cosmetic vehicle: at least one agent blocking the binding of α-MSH on the MC-1 receptors, at least one agent blocking the synthesis of ET-1, at least one SCF synthesis inhibiting agent, at least one tyrosinase inhibiting agent. 2 / Cosmetic composition according to claim 1, characterized in that the agent blocking the binding of α-MSH on the MC-1 receptors is hexapeptide 2 and / or nonapeptide 1 and represents between 0.00001 and 1% by weight. weight of the composition, preferably between 0.0001 and 0.0004% by weight. 3 / Cosmetic composition according to one of the preceding claims, characterized in that the agent blocking the synthesis of ET-1 is an extract of Andrographis paniculata leaves and represents between 0.001 and 10% by weight of the composition. 4 / Cosmetic composition according to one of the preceding claims, characterized in that the inhibiting agent for the synthesis of SCF and the synthesis of tyrosinase is the same and is an aqueous extract of Palmaria palmata representing between 0.01 and 25% by weight. weight of the composition. 5 / Cosmetic composition according to one of claims 1 to 4, characterized in that it further contains: at least one UVB filter and / or UVBIUVA, at least one UVA filter, optionally at least one mineral screen. 6 / Cosmetic composition according to claim 5, characterized in that the nature of the organic UVB or UVA / UVB filters and their proportion are chosen to give the composition an SPF of at least 20, advantageously at least 50.7 / Cosmetic composition according to claim 5, characterized in that the organic UVA or UVB filters are chosen from the group comprising para-aminobenzoic acid derivatives, salicylic derivatives, dibenzoylmethane derivatives, cinnamic derivatives, benzophenone derivatives, benzylidenecamphor derivatives: benzimidazole derivatives, triazine derivatives, benzotriazole derivatives, anthranilic derivatives, imidazoline derivatives, diethylamino hydroxybenzoyl hexylbenzoate and mixtures thereof, these filters representing between 2 and 40% by weight of the composition. 8 / cosmetic composition according to claim 5, characterized in that the inorganic screens are selected from the group comprising TiO2, ZnO. 9 / Use of the composition according to one of claims 1 to 4 as anti-pigmenting agent. 10 / Use of the composition object of one of claims 5 to 8 as anti-tanning agent. 11 / Use of the composition object of one of claims 5 to 8 as agent 20 blocking hyperpigmentation induced by UV.