FR3007284B1 - SYNERGISTIC ASSOCIATION OF THREE LIPOPHILIC COMPOUNDS AND USES THEREOF - Google Patents

Abstract

The invention relates to a combination of at least one compound (a) derived from the condensation of at least one fatty acid with an alkanolamine, at least one sterol (b) and at least one fatty alcohol (c). , each of (a), (b) and (c) being present in a proportion of at least 1% by weight relative to the mass of the combination, and the uses of this combination, especially in cosmetology, pharmacy, in dermatology and in the treatment of various media.

Description

The invention relates to a synergistic combination of at least three lipophilic compounds, and its use in cosmetology, dermatology, pharmacology and all other fields aimed at moisturizing, softening or protecting different surfaces including the skin and superficial body growths.

The skin is an organ that covers the structure of the body and protects it from the outside environment; it is the seat of multiple controlled exchanges between the interior and exterior environments. It is structured in two main compartments: the epidermis covering the surface of the skin, and the deep dermis. The epidermis is an epithelium subdivided into several layers from the basal layer just above the dermis, through the granular and spinal layers, to the upper layer, the most superficial, the stratum corneum or stratum corneum.

The stratum corneum, thanks to its cohesive structure and despite its small thickness (10pm), is the main barrier of the skin vis-à-vis physical aggression (UV rays ...), chemical (products coming into contact with the skin ...), mechanical (cutting, pinching ...). It acts as a reservoir against substances applied to the skin and effectively participates in the hydration phenomenon of the upper layers of the epidermis.

The stratum corneum is composed of corneocytes, keratinized cells, very elongated, and almost completely dehydrated, which overlap each other like the tiles of a roof. These cells are biologically dead but nonetheless remain active, with regard to their cohesion and their keratin-based constitution. Their cohesion is ensured by a cement based on lipids, fatty acids and ceramides. This compact and dense structure will slow or even prevent the penetration of exogenous substances, while slowing the diffusion of water from the dermis, which contributes to the hydration of the upper layers of the epidermis.

The second compartment of the skin is the dermis. It is the main water reservoir of the skin, thanks to proteoglycans such as hyaluronic acid, molecules with exceptional hygroscopic properties. The water content of the dermis is 80%, while that of the stratum corneum (stratum disjunctum) is only 15% water, or even 7% in the case of dry skin. The free water contained in the dermis diffuses from the deepest layers to the most superficial layers, through a network defined by the intercellular lipid spaces. The alteration of these lipids causes an increase in water loss, the skin dries up and loses suppleness and elasticity.

An alteration of the cohesion between the corneocytes, causes an increase of the water loss (PIE, insensible loss in water). In the case of extremely dry skin, it loses its flexibility and elasticity.

The present invention provides a solution for strengthening the barrier function of the skin.

The present invention provides a solution to the toxicity of certain substances intended to be in contact with the skin such as pigments, perfumes, preservatives, solvents, detergents and / or any other potentially toxic or harmful substances.

The present invention provides a solution to the volatility of certain molecules or substances intended to come into contact with the skin such as perfumes.

The present invention provides a solution to the solubility of certain substances with water such as mineral filters.

According to the invention, the solution resides in a combination of at least the following three lipophilic compounds: at least one compound (a) resulting from the condensation of at least one fatty acid with at least one alkanolamine, at least one sterol (b), and - at least one fatty alcohol (c), each of (a), (b) and (c) being present in a proportion of at least 1% by weight relative to the mass of the combination .

According to the invention, this combination can be used alone or included in various compositions intended to be applied to the skin or any other support in order to protect them from exogenous alterations such as the penetration of substances, the leaching with water or the mechanical friction.

The combination mentioned above makes it possible to reduce the volatility of certain substances. By limiting the diffusion, the invention, alone or in preparation, increases the olfactory remanence of the odorants. The invention relates to any form of cosmetic, dermatological or pharmaceutical compositions intended to maintain the substances of the composition at the level of the contact zone. By limiting the penetration and / or passive diffusion, the invention reduces the toxicity of the substances included in the composition and improves the desired effect by increasing the remanence. This is particularly the case for sunscreens or pigments contained in the make-up.

According to the invention, the combination of the three lipophilic compounds mentioned above may be used alone or included in all forms of cosmetic, dermatological or pharmaceutical compositions intended to moisturize, soften and / or reduce the insensible loss of water. The invention promotes the cohesion of corneocytes, dead cells and keratinized skin, superficial body growths or leather and strengthens interconteocyte cement conferring flexibility and hydration to treated media whether it is skin, superficial body growths or leather. In the context of the skin, this hydration of the upper layers of the epidermis will be further enhanced by the action of the invention on the intercorneocyte lipid structure compact structure and dense whose strengthening will slow the insensible loss of water from of the dermis.

According to the invention, the protective functions with respect to exogenous factors, whether chemical or mechanical, the functions of reducing toxicity, increasing remanence and / or hydration can be obtained by addition and / or direct inclusion of the combination in the compositions or applied before or after the products and / or assets concerned. By way of example, the combination may be included directly in a foundation base to oppose the passive diffusion of the pigments through the skin and increase the hold of said foundation or included in the day cream intended to be applied before laying the foundation with an identical result. Conversely, the combination may be included in a serum to increase its moisturizing power or included in an additional cream to be applied after the serum to promote its penetration, limit its interaction with other products and enhance its moisturizing power by limiting the insensitive loss in water.

Depending on whether the invention is included in the composition or applied before or after, the synergy targeted with other substances will be different. Applied before, the invention or composition containing a combination of the invention, will serve as a support for the active ingredients applied thereafter, limit their passive diffusion, reduce their toxicity and increase their persistence on the surface of the skin. Applied thereafter, the invention or a composition containing a combination of the invention, will promote the penetration of any substances applied before it, isolate them from possible interactions with the external environment, promote hydration of the upper layers of the epidermis and slow down insensible loss of water. Thus, the possible use of a highly bioavailable product will advantageously be supplemented by the use after a composition containing the combination. The combination of the two products will limit the volatility of the first product, will increase its penetration, will moisturize the upper layers of the epidermis and slow down the insensitive loss of water often associated with the use of this type of molecules such as alcohol essential oils and / or any other substances of low molecular weight and / or high volatility. The invention is hereinafter described in more detail, each of the following features being considered alone or in combination.

The compound (s) (a) are obtained by condensation of at least one fatty acid and at least one alkanolamine.

All fatty acids can be condensed with the alkanolamine (s). Thus, they are chosen from saturated fatty acids, mono- and polyunsaturated fatty acids and their mixtures. Advantageously, the compound (s) (a) are derived from at least one saturated fatty acid and / or monounsaturated fatty acid. More preferably, they are derived from at least one saturated fatty acid. As examples of fatty acids, mention may be made of: among saturated fatty acids: formic acid (or methanoic acid) C1: 0 acetic acid (or ethanoic acid) C2: 0 propionic acid (or propanoic acid) C3: 0 butyric acid (or butanoic acid) C4: 0 valeric acid (or pentanoic acid) C5: 0 caproic acid (or hexanoic acid) C6: 0 enanthic acid (or heptanoic acid) C7: 0 caprylic acid (or octanoic acid) C8: 0 pelargonic acid (or nonanoic acid) C9: 0 capric acid (or decanoic acid) C10: 0 undecylic acid (or undecanoic acid) C11: 0 lauric acid (or dodecanoic acid) C12: 0 tridecyl acid (or tridecanoic acid) C13: 0 myristic acid (or tetradecanoic acid) C14: 0 pentadecyl acid (or pentadecanoic acid) C15: 0 palmitic acid (or hexadecanoic acid) 016: 0 margaric acid (or heptadecanoic acid) 017: 0 stearic acid (or octodecanoic acid) 018: 0 nonadecyl acid (or nonadecanoic acid) 019: 0 ac arachidic acid (or eicosanoic acid) 020: 0 behenic acid (or docosanoic acid) 022: 0 lignoceric acid (or tetracosanoic acid) 024: 0 cerotic acid (or hexacosanoic acid) 026: 0 montanic acid (or octacosanoic acid) 028: 0 melissic acid (or triacontanoic acid) 030: 0 laceroic acid (or dotriacontanoic acid032: 0 among monounsaturated fatty acids: palmitoleic acid (or 9Z-hexadecenoic acid) 016: 1 ω-7 oleic acid (or 9Z-octadecenoic acid) 018: 1 ω-9 erucic acid (or 13Z-docosaenoic acid) 022: 1 ω-9 nervonic acid (or 15Z-tetracosaenoic acid) 024: 1 ω-9 among polyunsaturated fatty acids: linoleic acid (or 9Z acid 12Z-octadecadienoic) 018: 2 ω-6 α-linolenic acid (or 9Z, 12Z, 15Z-octadecatrienoic acid) 018: 3 ω-3 γ-linolenic acid (or 6Z, 9Z, 12Z-octadecatrienoic acid) 018: 3 ω-6 dihomo-y-linolenic acid (or 8Z, 11Z, 14Z-eicosatrienoic acid) 020: 3 ω-6 arachidonic acid (or a 5Z, 8Z, 11Z, 14Z-eicosatetraenoic acid) C20: 4 ω-6 eicosapentaenoic acid (or 5Z, 8Z, 11Z, 14Z, 17Z-eicosapentaenoic acid) 020: 5 ω-3 docosahexaenoic acid (or 4Z, 7Z acid, 1 OZ, 13Z, 16Z, 19Z-docosahexaenoic) 022: 6 ω-3.

In one variant of the invention, the fatty acid or acids condensed with the alkanolamine may be those of a mixture of fatty acids of an oil and / or a butter.

Among the preferred oils, mention may be made of the following: laurel bay oil, comprising:> saturated fatty acids (28.63%), of which lauric acid (11.61%), palmitic acid (14.87%), stearic acid (1.55%), myristic acid (0.60%)> monounsaturated fatty acids: oleic acid (40.32%)> polyunsaturated essential fatty acids: linoleic acid (23.80%), linolenic acid ( 0.83%). - Palm oil, derived from the fruit pulp of the Elaeis guineensis palm, and comprising:> saturated (48.8%) GA including palmitic acid (44.0%), stearic acid (4.4%)> AG mono-unsaturates: oleic acid (38.4%)> polyunsaturated essential fatty acids: linoleic acid (omega 6) (9.4%) - palm kernel oil, derived from the seed of the palm fruit Elaeis guineensis, and comprising:> saturated fatty acids (82%) including lauric acid (48.2%), myristic acid (16.2%), palmitic acid (8.4%), capric acid (3.4%), caprylic acid (3.3%) %), stearic acid (2.5%)> monounsaturated fatty acids: oleic acid (15.3%)> polyunsaturated fatty acids: linoleic acid (2.3%)

In a list of preferred butters according to the invention, in particular because of their high saturated fatty acid content, the following butters are found: Murumuru butter, derived from the pressure of the seed of the Astrocaryummurumuru tree, and comprising :> Saturated AG (88.6%) including lauric acid (49.8%), myristic acid (23.5%), palmitic acid (5.8%), stearic acid (3.4%), capric acid ( 2.1%), caprylic acid (4.0%)> monounsaturated fatty acids: oleic acid (omega 9) (7.1%)> polyunsaturated essential fatty acids: linoleic acid (omega 6) (3.1%) ) - Tucuma butter. obtained from an Amazonian palm tree, Astrocaryumtucuma, and comprising:> saturated AG: lauric acid (46.28%), myristic acid (23.29%), stearic acid (5.54%), acid palmitic (5.99%)> mono-unsaturated fatty acids: oleic acid (omega-9) (10.60%)> polyunsaturated essential fatty acids: linoleic acid (omega-6) (3.15%) - butter cocoa, obtained from the cold pressing of the cocoa bean (Theobroma cacao), and comprising:> saturated fatty acids (59.2%) including stearic acid (33.0%), palmitic acid (26.2%)> AG mono-unsaturates: oleic acid (33.2%)> polyunsaturated essential fatty acids: linoleic acid (omega 6) (3.3%) - Cupuaçu butter, derived from the seed of a tree, Theobromagrandifolium. and comprising:> saturated (49%) AG including stearic acid (30.8%), arachidic acid (10.7%), palmitic acid (7.5%)> monounsaturated AG: oleic acid (omega-9) (41.7%)> polyunsaturated essential fatty acids: linoleic acid (omega-6) (5.0%) - Sal butter or tallow from Borneo, obtained from the cores of Shorea robusta fruits, and comprising: > Saturated AG (55.6%) including stearic acid (42.7%), palmitic acid (12.9%)> mono-unsaturated fatty acids: oleic acid (omega-9) (37.30%)> polyunsaturated essential fatty acids : linoleic acid (omega-6) (2.1%) - Kokum butter, also called Gurgi nut fat, derived from the seed of Garcinia indica, and including:> saturated (51.83%) AG including palmitic acid ( 17.55%), stearic acid (34.28%)> monounsaturated fatty acids: oleic acid (omega-9) (34.96%)> polyunsaturated essential fatty acids: linoleic acid (omega-6) (4, 08%) - Kpangnan butter. also called golden shea butter or butter

Kanya, from the Pentadesma butyracea seed, and comprising:> saturated (47.7%) fatty acids including stearic acid (40.00%), palmitic acid (7.70%)> monounsaturated fatty acid: oleic acid (42%) , 30%)> Polyunsaturated essential fatty acids: linoleic acid (omega 6) (4.40%) - Mango butter, obtained by cold pressing of the mango kernel kernel, and comprising:> saturated fatty acids (54.56%) of which iso-stearic acid (36.66%), palmitic acid (14.96%)> mono-unsaturated fatty acids: oleic acid (omega-9) (39.87%)> poly-essential fatty acids unsaturated: linoleic acid (omega-6) (4.56%)

In this list, the proportions of AG are expressed as AG mass per 100 g of butter. The alkanolamine leading to the compound (s) (a) corresponds to the formula N (H) n [(CH 2) mOH] p [(CH 2) nOH] pOÙ n is equal to 0, 1 or 2, p and p ', identical or different, are equal to 1,2 or 3, with n + p + p' = 3, and m and rr, identical or different, vary from 1 to 10, preferably from 1 to 5. Advantageously, the alkanolamine is chosen from mono-, di- and triethanolamine. More preferably, it is diethanolamine.

Thus, according to an advantageous combination, the compound or compounds (a) are chosen from lauric diethanolamide and any mixture of lauric diethanolamide with another compound (a) derived from the condensation of a fatty acid with an alkanolamine.

The sterol (s) (b) are selected from any lipid having a sterane nucleus. Representative sterols are cholesterol, lanosterol, phytosterols such as sitosterol, campesterol, and stigmasterol, as well as ergosterol.

According to an advantageous combination, the sterol (s) (b) are chosen from cholesterol, lanosterol, phytosterols, ergosterol, and any mixture thereof with another sterol. The fatty alcohol (c) is a carbon chain alcohol having most of them an even number of carbon atoms, said chain being linear or branched. Preferably, it comprises from 4 to 36 carbon atoms, preferably from 8 to 30, and more preferably from 14 to 24 carbon atoms.

For example, the following pure fatty acids may be mentioned: octan-1-ol and 2-ethyl-1-hexanol (C8)

Nonan-1-ol (C9)

Decan-1-ol (C10) Undecanol (C11)

Dodecan-1-ol or lauryl alcohol (C12)

Tetradecanol or myristyl alcohol (C14)

Hexadecanol or cetyl alcohol (C16) or H3C- (CH2) 15-OH octadecanol or stearyl alcohol (C18)

The docosanol (C22)

Policosanol (C26-36)

Triacontanol (or myricylic alcohol) (C30).

Preferably, it is a mixture of fatty alcohols, such as cetostearyl alcohol.

For the purposes of the invention, the ingredients which contain fatty alcohols may be used for producing the mixture (for example lanolin alcohol). Lanolin alcohol (CAS: 8027-33-6, INCI: Lanolinalcohol) is a lanolin derivative which corresponds to the unsaponifiables of lanolin.

According to an advantageous combination, the fatty alcohol (s) (c) are chosen from cetostearyl alcohol, lanolin alcohol and any mixture of these with another fatty alcohol.

A combination of the invention is prepared by simple mixing of the various compounds (a), (b) and (c), in an indifferent order. Given their nature and therefore their presentation, heating preferably until the fusion of the compounds is necessary to obtain a complete mixture. Advantageously, this heating is performed after mixing the compounds, but alternatively, each compound (a), (b) and (c) can be first melted and then mixed, whether or not the heating continues.

A combination of the invention preferably corresponds to the following characteristics, considered independently of one another: the proportion of the compound (s) varies from 60 to 80% by weight relative to the weight of the combination; the proportion of sterol (s) (b) varies from 5 to 25% by weight relative to the mass of the combination; the proportion of the compound (s) (c) varies from 5 to 25% by weight relative to the mass of the combination; it comprises, or consists of, lauric diethanolamide, cholesterol, and cetostearyl alcohol; advantageously, lauric diethanolamide is present in a proportion ranging from 60 to 80%, cholesterol in a proportion ranging from 5 to 25%, and cetostearyl alcohol in a proportion ranging from 5 to 25%, the proportions being expressed in mass relative to the mass of the combination. The invention also relates to a composition comprising a combination of the invention, and optionally an acceptable vehicle.

It also relates to a cosmetic, pharmaceutical, or dermatological composition for topical use, comprising a combination of the invention, and excipients acceptable from a cosmetic, pharmaceutical or dermatological point of view, and optionally one or more cosmetic, pharmaceutical or dermatological active ingredients.

In all the compositions, whether cosmetic, dermatological, pharmaceutical or for the treatment of a support, the proportion of the combination is at least 0.1% by weight relative to the mass of the composition. This proportion can reach 60% but will generally be between 1% and 5%. The other constituents are chosen from the usual additives or adjuvants such as, for example, preserving agents, perfumes, gelling agents, surfactants, emulsifiers, hydrophilic compounds, lipophilic compounds, silicones or minerals. One or more ingredients or active ingredients may be incorporated: for example, active ingredients intended to participate in the protection of the skin vis-à-vis external aggression and / or limit insensible loss of water. It being understood that whatever the ingredient concerned, a better efficacy of said ingredient is observed as soon as it is added to the combination of the invention.

In cosmetics, a combination of the invention is intended to be used alone or included in ointments, lotions, gels, emulsions whether oil in water, water in oil, containing silicones and / or dispersible substances.

Finally, the present description refers to any type of composition whether it is for cosmetic, dermatological, pharmacological or any other application. Preventive treatment or maintenance can be envisaged for any type of support, such as leather, wood, porous floors, paint or fabrics, especially with a view to increasing their resistance to water or friction, or any other chemical, mechanical or thermal aggression.

The present invention is now illustrated, without limitation, by the following examples in support of FIGS. 1-6, in which:

FIG. 1 is a diagram showing the cutaneous hydration (in% gain) of a combination of the invention, as a function of the proportions of the ingredients (a), (b) and (c).

FIG. 2 is a diagram representing the cutaneous hydration (in% gain) of a composition of the invention, as a function of the proportion of the combination F, in said composition.

Figures 3 and 4 correspond to photographs illustrating the protective role vis-à-vis the skin of a combination of the invention, with respect to a coloring agent:

Figures 5 and 6 correspond to photographs illustrating the protective role vis-à-vis the nail of a combination of the invention with respect to a coloring agent:

FIG. 7 corresponds to photographs illustrating the role of maintaining an active principle, namely sunscreens, on the superficial layer of the skin, over time, when said active ingredient is applied in a combination of the invention ( A) and when applied directly (B).

Example 1: Preparation of combinations of the invention

Various combinations of the invention are prepared from (a) lauric diethanolamide, (b) cholesterol and (c) cetearyl alcohol, the proportions of which, by weight relative to the total mass of the combination, have varied from 0-100% for (a) and 0-50% for each of (b) and (c).

The constitution of the prepared combinations is specified in the following table 1: Reference of the. . (A) (b) (c) combinaison____ _______A__100__0__0_______ _________B__98__1__1__________ ________ _______ C__95__2,5__2,5 _______D__90__5__5________ ________E__80__10__10_______ ________F__70__15__15_______ _______G__60__20__20_______ _______H__50__25__25_______ _________I__40__30__30________ ________J__30__35__35_______ _______K__20__40__40_______ ________L__10__45__45_______ ________ ________ M__5__47,5__47,5 N__2,5__48,75__48,75 ________ O__1__49,5__49,5 P | 0 | 50 | 50

Each of these compositions was prepared according to the following protocol for a total mass of 100 g: - the various compounds (a), (b) and (c) are weighed in a 250 ml beaker as indicated in the table above ; the mixture is heated until the complete dissolution of the compounds is achieved; - The mixture is homogenized using a mixer (different types of mixers can be used: spatula, vortex, propeller, ...) - and let the mixture cool.

An efficiency on the tests carried out (described in the following examples) was observed on all the combinations associating the 3 lipophilic compounds, as soon as they are present, each at a rate of at least 1% by mass relative to the mass. of the combination, that is to say for the samples B, C, D, E, F, G, H, I, J, K, L, M, Net O. The optimal efficiency was observed with the sample F (70% lauric diethanolamide, 15% cholesterol and 15% cetostearyl alcohol)

Example 2: Efficacy on cutaneous hydration

Influence of the proportions of the various ingredients (a), (b) and (c):

Cosmetic compositions were formulated with the combinations A to P of Example 1 and a gelling base consisting of water and Prodhycreme® 013; for each composition, the proportion of the combination was 10%, that of Prodhycreme® 013 of 10% and that of water of 80%, the percentages being given in mass relative to the total mass of the composition.

A skin hydration test was performed on the arm.

The following procedure was followed to evaluate the effects of different compositions on cutaneous hydration.

The measuring points are identified by marks (dots) made with red felt on both arms. The cutaneous hydration can be very variable depending on the measurement zone, all measurement points were made (before-after) exactly at the same point. Cutaneous hydration was measured using the Multi Dermascope® MDS 800. This device is equipped with probes to measure the degree of hydration of the skin. It indicates on a chain of half-moon diodes the percentage of hydration of the skin. For each condition, 5 measurements were obtained.

Value = measurement after application of the composition - measurement before application

These values therefore correspond to the effect of the application of the composition on the percentage of hydration.

The results of the test are shown in FIG. 1. The optimum efficiency was observed with the cosmetic composition containing 10% of the combination F with a hydration gain of 25%.

Influence of the proportion of the combination in the composition:

Cosmetic compositions were formulated with a proportion of the combination F of Example 1, ranging from 0-100%.

The test results are shown in Figure 2.

The present invention, when incorporated in a cosmetic formula between 1% and 100% promotes cutaneous hydration.

A combination of the invention can therefore be used in cosmetic compositions from 1% by weight relative to the mass of the composition, to promote skin hydration.

In the following examples, the performance of a combination of the invention is illustrated. Combination F of Table 1 above was selected. The invention is of course not limited to this combination alone, since, as demonstrated in Example 1, the presence of at least 1% by mass relative to the mass of the combination, in a combination of the invention allows to obtain the desired technical effect.

Example 3: Efficacy on skin protection

A skin protection test was performed with the combination F, as follows.

In order to demonstrate the maintenance of the active ingredients on the surface without diffusion through the layers of the epidermis, the combination F was stained with a blue dye. The colored combination F (FIG. 3A) or the dye alone (FIG. 3C) were applied to the skin. One minute after the application the products were wiped without rinsing. The dye penetrated the skin in the control case (FIG. 3D) while it did not penetrate with the combination of the invention (FIG. 3B).

Resistance tests were carried out with the same combination F.

For this, the colored combination F was applied to the skin, then a minute later, various rinses were performed (water: FIG. 4A, water with acidic pH: FIG. 4C, mechanical friction: FIG. 4E, detergents: FIG. 4G). After a minute, the dye is wiped off without rinsing. In all cases (water: FIG. 4B, water with acidic pH: FIG. 4D, mechanical friction: FIG. F, detergents: FIG. 4H), the dye did not penetrate and demonstrates the strength of the combination of the invention.

Example 4: Effectiveness on hair protection

Tests have been carried out on damaged hair (forked hair). The microscopic observation of this hair after application of the combination F mentioned above has shown that there was a complete restoration of the tip of the hair. This restoration is resistant to rinsing with water, acidic pH solution, mechanical rubbing, heat exposure, and rinsing / drying cycles.

Example 5: Efficiency on nail protection

A test identical to that of Example 3 was performed on the nails. The results are similar to those on the skin (maintenance of the dye surface and resistance to rinsing).

The results of the tests are shown in Figures 5 and 6.

Example 6: Efficacy on the maintenance of active ingredients on the surface of the skin

Combination F was added (FIG. 7A) or not (FIG. 7B) in a sunscreen containing physical filters (titanium dioxide) and applied to the skin (respectively FIG. 7A left and 7B left). The creams applied to the skin were rinsed with water for 5 minutes. The cream not containing said invention is not resistant to rinsing (Figure 7B right) while that containing said invention up to 10% resists rinsing (Figure 7A right).

Claims (9)

10. Combination according to any one of claims 1 to 9, characterized in that the lauric diethanolamide is in a proportion ranging from 60 to 80%, the cholesterol is in a proportion ranging from 5 to 25%, and the cetostearyl alcohol is in a proportion ranging from 5 to 25%, the proportions being expressed by weight relative to the mass of the combination. 11. Use of a combination according to any one of claims 1 to 10, for preparing a cosmetic composition. 12. A combination according to any one of claims 1 to 10 for hydrating and reinforcing the cohesion of dead cells and keratinized skin, skin appendages or leather. 13. Combination according to any one of claims 1 to 10 for inducing a barrier effect by opposing the penetration of any exogenous substances through the skin. 14. Combination according to any one of claims 1 to 10 for inducing a protective effect against physical, chemical, mechanical or thermal alterations. 15. Combination according to any one of claims 1 to 10 for reducing the bioavailability of additional substances in the preparation and / or those applied after the combination to reduce in particular the risks of toxicity. 16. Combination according to any one of claims 1 to 10 for reducing the volatility of certain volatile and / or odorous substances so as to increase the olfactory remanence of the substances. 17. Combination according to any one of claims 1 to 10 for maintaining the substances at the contact area and increase the persistence of the effect. 18. Combination according to any one of claims 1 to 10 for promoting the penetration of the substances applied to the skin before the combination. 19. Combination according to any one of claims 1 to 10 for softening the skin, superficial body growths or leather. 20. Combination according to any one of claims 1 to 10 for curbing the insensitive loss of water from the dermis to the upper layers of the epidermis. CLAIMS A combination consisting of a compound (a) or more, the compound (a) being derived from the condensation of at least one fatty acid with an alkanolamine, a sterol (b) or more and a fatty alcohol ( c) or more, each of (a), (b) and (c) being present in a proportion of at least 1% by weight relative to the mass of the combination. 2. Combination according to claim 1, characterized in that the compound or compounds (a) are derived from the condensation of at least one fatty acid chosen from saturated fatty acids, monounsaturated and polyunsaturated fatty acids and mixtures thereof. with an alkanolamine. 3. Combination according to any one of claims 1 and 2, characterized in that the compound or compounds (a) are chosen from lauric diethanolamide and any mixture of lauric diethanolamide with another compound (a) resulting from the condensation of a fatty acid with an alkanolamine. 4. Combination according to any one of claims 1 to 3, characterized in that the sterol (s) (b) are chosen from cholesterol, lanosterol, phytosterols, ergosterol, and any mixture thereof with a other sterol. 5. Combination according to any one of claims 1 to 4, characterized in that the fatty alcohol (s) (c) are chosen from cetostearyl alcohol, lanolin alcohol and any mixture thereof with another alcohol. fat. 6. Combination according to any one of claims 1 to 5, characterized in that the proportion of the compound or compounds (a) varies from 60 to 80% by weight relative to the mass of the combination. 7. Combination according to any one of claims 1 to 6 characterized in that the proportion of the sterol (s) (s) varies from 5 to 25% by weight relative to the mass of the combination. 8. Combination according to any one of claims 1 to 7, characterized in that the proportion of the compound (s) (c) varies from 5 to 25% by weight relative to the mass of the combination. 9. Combination according to any one of claims 1 to 8, characterized in that the compound (a) is the lauric diethanolamide, the sterol (b) is cholesterol, and the fatty alcohol (c) is the cetostearyl alcohol .