Cosmetic or dermatological emulsion comprising a merocyanine and an emulsifying system containing a gemini surfactant

The present invention relates to a cosmetic or dermatological composition in emulsion form, comprising, in a physiologically acceptable support:

a) at least one aqueous phase and

b) at least one oily phase, and

c) at least one merocyanine compound of formula (1 ) which will be defined in greater detail herein below and

d) at least one emulsifying system containing at least one gemini surfactant.

Another subject of the present invention consists of a non-therapeutic cosmetic process for caring for and/or making up a keratin material, comprising the application, to the surface of the said keratin material, of at least one composition according to the invention as defined above.

The invention also relates to a non-therapeutic cosmetic process for limiting the darkening of the skin and/or improving the colour and/or uniformity of the complexion, comprising the application, to the surface of the keratin material, of at least one composition as defined previously.

The invention also relates to a non-therapeutic cosmetic process for preventing and/or treating the signs of ageing of a keratin material, comprising the application, to the surface of the keratin material, of at least one composition as defined previously.

It is known that radiation with wavelengths of between 280 nm and 400 nm permits tanning of the human epidermis and that radiation with wavelengths of between 280 and 320 nm, known as UV-B rays, harms the development of a natural tan. Exposure is also liable to bring about a detrimental change in the biomechanical properties of the epidermis, which is reflected by the appearance of wrinkles, leading to premature ageing of the skin.

It is also known that UV-A rays with wavelengths of between 320 and 400 nm penetrate more deeply into the skin than UV-B rays. UV-A rays cause immediate and persistent browning of the skin. Daily exposure to UVA rays, even of short duration, under normal conditions can result in damage to the collagen fibres and the elastin, which is reflected by a modification in the microrelief of the skin, the appearance of wrinkles and uneven pigmentation (liver spots, lack of uniformity of the complexion).

Protection against UVA and UVB rays is thus necessary. An efficient photoprotective product should protect against both UVA and UVB rays.

Many photoprotective compositions have been proposed to date to overcome the effects induced by UVA and/or UVB rays. They generally contain organic or mineral UV-screening agents, which function according to their own chemical nature and according to their own properties by absorption, reflection or scattering of the UV rays. They generally comprise mixtures of liposoluble organic screening agents and/or water-soluble UV screening agents in combination with metal oxide pigments, such as titanium dioxide or zinc oxide.

Many cosmetic compositions for limiting the darkening of the skin and improving the colour and uniformity of the complexion have been proposed to date. It is well known in the field of antisun products that such compositions may be obtained by using UV-screening agents, and in particular UVB-screening agents. Certain compositions may also contain UVA-screening agents. This screening system should cover UVB protection for the purpose of limiting and controlling the neosynthesis of melanin, which promotes the overall pigmentation, but should also cover UVA protection so as to limit and control the oxidation of the already-existing melanin leading to darkening of the skin colour.

However, no composition contains a particular combination of UV-screening agents that would be especially suited to photoprotecting the skin and particularly to improving the quality of the skin as regards both the colour and its mechanical elasticity properties.

Advantageously, this improvement is particularly visible on already-pigmented skin so as not to increase the melanin pigmentary load or the structure of the melanin already present in the skin.

In point of fact, the majority of the organic UV-screening agents consist of aromatic compounds which absorb in the wavelength range between 280 and 370 nm. In addition to their power for screening out sunlight, the desired photoprotective compounds should also have good cosmetic properties, good solubility in the usual solvents and in particular in fatty substances such as oils, and also good chemical stability and good photostability alone or in combination with other UV-screening agents. They should also be colourless or at least have a colour that is cosmetically acceptable to the consumer.

One of the main drawbacks known to date of these compositions is that these screening systems are insufficiently effective against UV rays and in particular against long UVA rays with wavelengths beyond 370 nm, for the purpose of controlling photo-induced pigmentation and its evolution by means of a system for screening out UV over the entire UV spectrum.

Among all the compounds that have been recommended for this purpose an advantageous family of UV-screening agents has been proposed, which consists of carbon-bearing merocyanine derivatives, which is described in patent US 4 195 999, patent application WO 2004/006 878, patent applications WO2008/090066, WO201 1/1 13718, WO2009/027258, WO2013010590, WO2013/01 1094, WO20130/1 1480 and the documents IP COM JOURNAL N°000179675D published on February 23, 2009, IP COM JOURNAL N°000182396D published on April 29, IP COM JOURNAL N° 000189542D published on November 12, 2009, IP COM Journal N°IPCOM00001 1 179D published on 03/04/2004. Some of these compounds may show the following drawbacks :

- relatively unsatisfactory solubility in the usual solvents and in particular in fatty substances such as oils which may require a laborious formulation process and/or may result in cosmetic drawbacks such as a greasy effect on application ;

- an unsatisfactory chemical stability and/or unsatisfactory photostability

- produce a color liable to discourage the consumer from using a cosmetic or dermatological composition containing them.

Antisun compositions are quite often in the form of an emulsion of oil-in-water type (i.e. a cosmetically acceptable support consisting of a continuous aqueous dispersing phase and of a discontinuous oily dispersed phase) or of the water-in-oil type (i.e. a cosmetically acceptable support consisting of a continuous oily dispersing phase and of a discontinuous aqueous dispersed phase) which contains, in varying concentrations, one or more conventional lipophilic and/or hydrophilic organic screening agents which are capable of selectively absorbing harmful UV rays, these screening agents (and the amounts thereof) being selected as a function of the desired sun protection factor.

The Applicant has found in the course of its research that some of the merocyanines could lose their efficacy in the presence of certain particular emulsifiers in antisun compositions. The Applicant has especially observed that some of these merocyanines degrade chemically in the presence of an emulsifying system containing at least one alkali metal salt of a phosphoric acid ester of a fatty alcohol.

There is thus still a need to select other families of emulsifiers which guarantee a good chemical stability of the merocyanines without the drawbacks as previously defined.

The Applicant has discovered, surprisingly, that the use of one emulsifying system containing at least one gemini surfactant and one merocyanine compound of formula (1 ) herein below make it possible to achieve this objective.

Furthermore, the merocyanine compounds of formula (1 ) herein below, present surprinsingly the advantage to be significantly less colored than the merocyanine compounds as disclosed in the application WO2008/090066 as the compound MC1 1 also called MC03 in the application WO2009/027258.

Those discoveries form the basis of the present invention.

Thus, in accordance with one of the objects of the present invention, a cosmetic or dermatological composition in emulsion form is now proposed, comprising, in a physiologically acceptable support:

a) at least one aqueous phase and

b) at least one oily phase, and

c) at least one merocyanine compound of formula (1 ) which will be defined in greater detail hereinbelow and

d) at least one emulsifying system containing at least one gemini surfactant.

Another subject of the present invention consists of a non-therapeutic cosmetic process for caring for and/or making up a keratin material, consisting in applying, to the surface of the said keratin material, at least one composition according to the invention as defined above.

The invention also relates to a non-therapeutic cosmetic process for limiting the darkening of the skin, improving the colour and uniformity of the complexion, comprising at least the application, to the surface of the keratin material, of at least one composition as defined previously.

The invention also relates to a non-therapeutic cosmetic process for treating the ageing of a keratin material, comprising at least the application, to the surface of the keratin material, of at least one composition as defined previously.

Other characteristics, aspects and advantages of the invention will emerge on reading the detailed description that follows.

The term "human keratin materials" means the skin (of the body, face and area around the eyes), hair, eyelashes, eyebrows, bodily hair, nails, lips or mucous membranes.

The term "physiologically acceptable" means compatible with the skin and/or its integuments, having a pleasant colour, odour and feel and not causing any unacceptable discomfort (stinging, tautness or redness) liable to discourage the consumer from using this composition.

The term "between X and Y" means the range of values also including the limits X and Y.

According to the invention, the term "preventing" or "prevention" means reducing the risk of occurrence or slowing down the occurrence of a given phenomenon, namely, according to the present invention, the signs of ageing of a keratin material.

The term "emulsion" means any macroscopically homogeneous, kinetically stable composition comprising at least two mutually immiscible phases; one being the dispersing continuous phase and the other being dispersed in the said continuous phase in the form of droplets. The two phases are kinetically stabilized by at least one emulsifying system generally comprising at least one emulsifying surfactant.

Emulsions are distinguished as being of the oil-in-water type, known as "direct" emulsions, consisting of an aqueous dispersing continuous phase and of an oily dispersed discontinuous phase, and emulsions of the water-in-oil type, known as inverse emulsions, consisting of an oily dispersing continuous phase and of an aqueous dispersed discontinuous phase. There are also multiple emulsions, for instance water-in-oil-in-water or oil-in-water-in-oil emulsions.

The term "emulsifying system" refers to any compound or mixture of compounds that is capable of increasing the kinetic stability of an emulsion. These compounds are generally amphiphilic and are surfactants characterized by their more or less hydrophilic or more or less lipophilic nature which will determine their ability to stabilize direct emulsions or inverse emulsions. They are especially classified by their HLB according to the calculation method of W.C. Griffin in the document "Classification of Surface Active Agents by HLB, Journal of the Society of Cosmetic Chemists 1 (1949) 31 1 " and in the document "Calculation of HLB of Non Ionic Surfactants, Journal of the Society of Cosmetic Chemists 5 (1954) 249". The calculation of the HLB according to this calculation method is performed according to the equation:

HLB = 20 X Mh/M

where Mh is the molar mass of the hydrophilic part of the surfactant and M is the total molecular mass of the molecule.

The term "gemini surfactant" means any dimeric molecule bearing two surfactant units each consisting of a hydrophilic head and a hydrophobic tail and connected together, at the hydrophilic heads, via a spacer group. For a detailed description of the various chemical structures and of their physicochemical properties, reference may be made to the following publications:

Milton J. Rosen, Gemini Surfactants, Properties of surfactant molecules with two hydrophilic groups and two hydrophobic groups, Cosmetics & Toiletries Magazine, vol. 1 13, December 1998, pp 49-55,

Milton J. Rosen, Recent Developments in Gemini Surfactants, Allured's Cosmetics & Toiletries Magazine, July 2001 , vol. 1 16, No. 7, pp 67-70.

MEROCYANINES

According to the present invention, the merocyanine compounds in accordance with the invention correspond to formula (1 ) below, and also the E/E- or E/Z-geometrical isomer forms thereof:

CLAIMS

1. Cosmetic or dermatological connposition in emulsion form, comprising, in a physiologically acceptable support:

a) at least one aqueous phase

b) at least one oily phase

c) at least one merocyanine compound of formula (1 ) or one of the E/E- or E/Z- geometrical isomer forms thereof:

in which:

R is a C1-C22 alkyl group, a C2-C22 alkenyl group, a C2-C22 alkynyl group, a C3-C22 cycloalkyl group or a C3-C22 cycloalkenyl group, the said groups possibly being interrupted with one or more O, and

d) at least one emulsifying system containing at least one gemini surfactant.

2. Composition according to Claim 1 , in which the merocyanine compound(s) are chosen from those in which:

R is a C1-C22 alkyl, which may be interrupted with one or more O.

3. Composition according to Claim 1 or 2, in which the merocyanine compound(s) are chosen from the following compounds, and also the E/E- or E/Z- geometrical isomer forms thereof:

4. Composition according to Claim 3, in which the merocyanine compound is 2- ethoxyethyl (2Z)-cyano{3-[(3-methoxypropyl)amino]cyclohex-2-en-1 - ylidene}ethanoate (2) in its E/Z geometrical configuration having the following structure:

and/or in its E/E geometrical configuration having the following structure:

5. Composition according to any one of Claims 1 to 4, in which the merocyanine(s) of formula (1 ) are present in a concentration ranging from 0.1 % to 10% by weight and preferentially from 0.2% to 5% by weight relative to the total weight of the composition.

6. Composition according to any one of Claims 1 to 5, in which the gemini surfactant(s) correspond to the following general formula:

in which:

Ri and R3 denote, independently of each other, an alkyl radical containing from 1 to 25 carbon atoms;

R2 denotes a spacer consisting of a linear or branched alkylene chain containing from 1 to 12 carbon atoms;

X denotes a group -(C2H4O)a-(C3H6O)bZ;

Y denotes a group -(C2H4O)c-(C3H6O)dZ;

in which

Z denotes a hydrogen atom or a radical -CH2-COOM, -SO3M, -P(O)(OM)2, -C2H4SO3M, -C3H6SO3M or-CH2(CHOH)4CH2OH group, in which M & M' represent H or an alkali metal or alkaline-earth metal or ammonium or alkanolammonium ion,

a and c, independently of each other, range from 0 to 15,

b and d, independently of each other, range from 0 to 10, and

the sum of a + b + c + d ranges from 1 to 25; and

n ranges from 1 to 10.

7. Composition according to Claim 6, in which, in formula (I), Ri and R3 preferably denote, independently of each other, an alkyl radical containing from 5 to 21 and more particularly from 7 to 19 carbon atoms.

8. Composition according to Claim 6 or 7, in which the gemini surfactant is such that each of the groups R1-CO- and R3-CO- comprises from 8 to 20 carbon atoms and preferably denotes a coconut fatty acid residue predominantly comprising lauric acid and myristic acid.

9. Composition according to any one of Claims 6 to 8, in which, in formula (I), b and d are equal to 0 and preferably the sum of a, b, c and d has a mean value ranging from 10 to 20 and is preferably from 12 to 18 and more particularly equal to 15;

preferably, Z is the group -SO3M in which M is preferably an alkali metal ion such as a sodium ion;

preferably, the spacer R2 consists of a linear C1-C3 alkylene chain and preferably an ethylene chain (-CH2CH2-);

n is preferentially equal to 0.

10. Composition according to any one of Claims 1 to 9, in which the gemini surfactant is disodium ethylene dicocamide PEG-15 disulfate, having the following structure:

RCO represents a coconut fatty acid radical and m + n has a mean value of 15.

11. Composition according to any one of Claims 1 to 10, in which the gemini surfactant is used as a mixture with other surfactants, and especially as a mixture with (a) a glyceryl ester of a C6-C22 fatty acid (preferably Ci4-C2o such as a stearate), (b) a diester of a C6-C22 fatty acid (preferably Ci4-C2o such as a stearate) and of citric acid and of glycerol (especially a diester of a C6-C22 fatty acid and of glyceryl monocitrate), and (c) a C10-C30 fatty alcohol (preferably behenyl alcohol).

12. Composition according to claim 1 1 , in which the gemini surfactant represents from 10% to 20% by weight and advantageously 15% by weight; the glyceryl ester of a C6-C22 fatty acid represents from 30% to 40% by weight, advantageously 35% by weight; the diester of a C6-C22 fatty acid and of citric acid and of glycerol represents from 10% to 20% by weight, advantageously 15% by weight; and the C10-C30 fatty alcohol represents from 30% to 40% by weight, advantageously 35% by weight, relative to the total weight of the mixture of surfactants comprising the gemini surfactant.

13. Composition according to Claim 1 1 or 12, comprising a mixture of disodium ethylene dicocamide PEG-15 disulfate, glyceryl stearate, glyceryl stearate monocitrate, behenyl alcohol, and preferably a mixture of from 10% to 20% by weight of disodium ethylene dicocamide PEG-15 sulfate, from 30% to 40% by weight of glyceryl stearate, from 10% to 20% by weight of glyceryl stearate monocitrate, and from 30% to 40% by weight of behenyl alcohol, relative to the total weight of the mixture of surfactants comprising the gemini surfactant.

14. Composition according to any one of Claims 1 to 10, in which the gemini surfactant is used as a mixture with an anionic surfactant such as a lauric acid ester, sodium lauroyl lactate.

15. Composition according to any one of the preceding claims, comprising the following mixtures of surfactants in which the gemini surfactant represents from 3% to 50% of the weight of these mixtures:

behenyl alcohol, glyceryl stearate, glyceryl stearate citrate and disodium ethylene dicocamide PEG-15 disulfate,

sodium lauroyl lactylate and disodium ethylene dicocamide PEG-15 disulfate capric/caprylic triglyceride, ceteareth-25, disodium ethylene dicocamide PEG-15 disulfate, sodium lauroyl lactylate, behenyl alcohol, glyceryl stearate, glyceryl stearate citrate.

16. Composition according to any one of the preceding claims, in which the gemini surfactant(s) are present in an active material content ranging from 0.05% to 10% by weight, preferably ranging from 0.1 % to 5% by weight and better still ranging from 0.2% to 2% by weight, relative to the total weight of the composition.

17. Composition according to any one of the preceding claims, in which the composition is in the form of an oil-in-water emulsion.

18. Non-therapeutic cosmetic process for caring for and/or making up a keratin material, comprising the application, to the surface of the said keratin material, of one composition as defined in any one of the preceding claims.

19. Non-therapeutic cosmetic process for limiting the darkening of the skin and/or improving the colour and/or uniformity of the complexion, comprising the application, to the surface of the skin, of one composition as defined in any one of the preceding claims.

20. Non-therapeutic cosmetic process for preventing and/or treating the signs of ageing of a keratin material, comprising the application, to the surface of the keratin material, of one composition as defined in any one of the preceding claims.