FR2943252A1 - Oil in water dermo-cosmetic emulsion, useful to e.g. treat/prevent itching on animal skin other than man, comprises micelles having an oil having active ingredient to diffuse through skin, water in which polysaccharide is dissolved - Google Patents

Abstract

Oil in water dermo-cosmetic emulsion comprises: micelles containing at least one oil containing an active ingredient to diffuse through the skin, where the micelles have a minimum size (D 10) of >= 0.1 mu m and a maximum size (D 90) of = 0.4 mu m; water in which polysaccharide is dissolved, where the polysaccharide is able to form a film, after polymerization, and is present at 0.7-5 mass% of emulsion. Independent claims are included for: (1) a preparation of the emulsion comprising mixing at least one oil comprising an active ingredient to diffuse through the skin, an emulsifier, water and polysaccharide capable of forming a film after polymerization, where the mixing is carried out and emulsifier and polysaccharide are chosen to obtain the emulsion, after mixing step; and (2) an animal other than man in which at least part of the skin carries the emulsion or the film resulting from polymerization of the polysaccharide of the emulsion. ACTIVITY : Antipruritic; Dermatological. MECHANISM OF ACTION : None given.

Description

TECHNICAL FIELD The present invention relates to a detiffo-cosmetic emulsion. The invention also relates to a process for preparing said emulsion and to its uses, in particular in the field of animal cosmetics. State of the art to facilitate the penetration of active ingredients into the skin, it is known to use an oil-in-water emulsion having micrometric size oil globules. Such an emulsion however has the disadvantage of rapidly penetrating the skin 10 and is therefore not permanently effective. There is therefore a need for a composition capable of ensuring both a rapid diffusion of active ingredients, but also deep and prolonged in time.

SUMMARY AND OBJECT OF THE INVENTION The invention provides an oil-in-water dermo-cosmetic emulsion comprising: micelles containing at least one oil containing an active ingredient to diffuse through the skin, said micelles having a minimum size D10 greater than or equal to 0.1 μm and a maximum size D 90 less than or equal to 0.4 μm. water in which a polysaccharide is dissolved, said polysaccharide being capable of forming, after polymerization, a film, and representing more than 0.7% and less than 5.0% of the emulsion, in percentages by weight.

Surprisingly, the inventors have found that the combination in a micelle emulsion containing at least one oil containing an active ingredient and having a minimum size Dlo greater than or equal to 0.1 lam and / or a maximum maximum size D90 or equal to 0.4 m, with water containing a polysaccharide capable of forming, after polymerization, a film, in the proportions according to the invention, advantageously makes possible a controlled diffusion of the active ingredients of the emulsion: in particular, the micelles ensure a diffusion of the active ingredients deep in the skin, fast and effective; however, the film formed from the polysaccharide has a moderating effect on this diffusion. Without being bound by this theory, the inventors consider that the film retains active ingredients, thus making it possible to prolong their diffusion in depth in the skin over time. The film also has the advantage of effectively protecting the surface of the skin from external aggression. As will be seen in more detail in the rest of the description, a dermocosmetic emulsion according to the invention can be used to treat or prevent pruritus, and in particular pruritus on atopic skin, and more specifically pruritus on a skin affected by atopic dermatitis.

Preferably, the polysaccharide is selected from the group consisting of cationic, anionic, nonionic polysaccharides and mixtures thereof. More preferably, the polysaccharide is natural or semi-natural. The polysaccharide may be derived from the fermentation of bacteria on a plant substrate and may in particular be chosen from the group formed by xanthan gums, gellan gums, pectins, alginates, succinoglycans, hydroxyethylcelluloses and carboxymethylcelluloses. , and their mixtures. Still preferably, the polysaccharide is an anionic polysaccharide of molecular weight greater than 106 Da. Preferably, the polysaccharide content is less than 4.0%, more preferably less than 3.0%. A content of 2.0% is, for example, well suited. Preferably, said active ingredient to diffuse through the skin is of natural plant origin. Still preferably, the emulsion comprises at least one constituent selected from a soothing agent, an essential fatty acid, an antiseptic essential oil, a spinach caper extract, lactic acid and mixtures thereof. Preferably, an emulsion according to the invention comprises more than 50% and / or less than 90% water. An emulsion according to the invention may also comprise usual cosmetic additives, chosen in particular from the group formed by antioxidants, preservatives, neutralizers, surfactants, sunscreens, sweeteners, surfactants, cosmetic stabilizers and adjusters. pH, vitamins, moisturizers, free antiradical agents, sequestering agents, hydrophilic active agents, lipophilic active agents, including animal, vegetable, mineral or synthetic waxes, and mixtures thereof.

The additives (constituents other than water, the polysaccharide and said oil containing an active ingredient) preferably represent more than 5% and less than 15.5%, in percentages by weight, of the emulsion. The invention also proposes a method for manufacturing an oil-in-water dermocosmetic emulsion comprising a step of mixing at least one oil which contains an active ingredient to be diffused through the skin, an emulsifier, an water and a polysaccharide capable of forming, after polymerization, a film; the mixing being carried out and the emulsifier and the polysaccharide being chosen so as to obtain, after said mixing step, a dermo-cosmetic emulsion according to the invention.

Preferably, the emulsifier comprises water, an emollient, a thickener, a viscosity adjuster, an emulsifier, a humectant, a conditioner. The emulsifier may in particular comprise diglycerin. Preferably, the emulsifier content is greater than 10%, preferably greater than 12% and / or less than 25%, preferably less than 22%.

Preferably, an emulsion according to the invention is intended to be applied to the skin of an animal other than man, and in particular a cat, a dog, a horse, or new animals of company such as a rat, a rabbit, a pig. Whatever the embodiment, preferably an emulsion according to the invention is in the form of a homogeneous liquid, capable of being vaporized. The invention also relates to a spray pump bottle or an aerosol container containing an emulsion according to the invention. Such a package is advantageously well suited to an application on an animal other than man. The invention also relates to an animal other than the human whose at least part of the skin carries an emulsion according to the invention or manufactured according to a process according to the invention, or a film resulting from a polymerization of a polysaccharide of such an emulsion. The animal may in particular be a mammal or a fur animal. The animal may especially be a cat, a dog, a horse or a new pet such as a rat, a rabbit, a pig. The invention also relates to the use of a dermo-cosmetic emulsion according to the invention as a medicament, in particular for the treatment of pruritus and / or utopic dermatitis.

The invention finally relates to a cosmetic process for the care and / or treatment of the skin, comprising a step of applying to the latter an emulsion according to the invention or manufactured according to a process according to the invention.

Definitions Emulsion means a homogeneous mixture of at least two immiscible liquids, thus constituting at least two phases, at least one phase being dispersed in another phase in the form of micelles. Traditionally, oil-in-water emulsion is an oil-containing micelle emulsion dispersed in water. 1.0 The percentiles (r percentiles in English) 10 (D10) and 90 (D90), are the micelle sizes of an emulsion corresponding to the percentages by number, of 1.0% and 90% respectively, on the cumulative distribution curve of the sizes micelles of the emulsion, the sizes of the micelles being ranked in ascending order. Thus, 10% by number of the micelles of the emulsion have a size less than D10 and 90% by number of the micelles have a size greater than D10. In this case, the minimum size is the percentile D10. In addition, 90% by number of the micelles of the emulsion have a size less than D90 and 10% by number of the micelles have a size greater than D90. The maximum size is the percentile D90. The size of a micelle is understood to mean its diameter as measured by means of a COULTER COUNTER apparatus. The percentiles can be determined using a micelle size distribution curve made using this device. In general, the principle of a COULTER COUNTER is as follows. The particles to be counted and / or measured are suspended in an electrolytic solution. The solution is passed through a calibrated micro-orifice, separating two electrodes between which a current is established. When a particle passes through the orifice, it moves its own volume of electrolyte solution, causing a momentary increase in the impedance measured between the two electrodes. This impedance variation generates a pulse that is transmitted back to the device. Since the height of the pulse is proportional to the volume of the particle, the analysis of the pulses makes it possible to acquire a size distribution curve, which is a function of the volume and the diameter of the particles.

By film is meant a dry coating, preferably flexible enough to adapt to the movements of the skin on which the film is disposed. A film thus constitutes a kind of second skin, protecting the underlying skin. By active principle is meant a constituent capable of interacting with cells of the different layers of the skin, in particular the epidermis and in particular the stratum corneum, for aesthetic and / or therapeutic purposes. By soothing agent is meant an agent capable of soothing the itching, which decreases and / or inhibits the sensations of skin discomfort such as irritation sensations, tingling, tightness, or a desensitizing agent.

"Essential oil" means a concentrated liquid of hydrophobic plant aromatic compounds obtained by distillation, in particular by steam distillation or by dry distillation, or by cold expression, or by chemical extraction with a solvent, or by supercritical CO2 extraction. By antiseptic is meant an agent that has the property of preventing or stopping the growth of bacteria or virus on the surface of the skin of a living being. Unless otherwise stated, the percentages used to define an emulsion refer to percentages by weight based on this emulsion.

Detailed Description Other features and advantages of the invention will become apparent on reading the detailed description which follows. A dno-cosmetic emulsion according to the invention comprises a polysaccharide capable of forming, after polymerization, a film comparable to a second skin. The polysaccharide is preferably capable of forming, after polymerization, a film which is not very tacky or not tacky, and which is preferably permeable to water and / or air. All polysaccharides known to have such properties can be envisaged. Preferably, the polysaccharide is selected from the group consisting of cationic, anionic, nonionic polysaccharides and mixtures thereof. More preferably, the polysaccharide is natural or semi-natural.

As natural or semi-natural cationic polysaccharide, a chitosan, a cationic guar gum, a cationic hydroxyethylcellulose are especially understood.

As natural or seri-natural anionic polysaccharide, an alginic acid, a hyaluronic acid, a chondroitin sulfate, an acacia, a karaya gum, a gum tragacanth, a carboxymethyl chitin, a cellulose gum, a gum gellan, xanthan gum, pectin, alginate and succinoglycan. As natural or semi-natural non-ionic polysaccharide, a starch, a dextrin, a guar gum, a cellulose ether, in particular a methylcellulose, a nitrocellulose, a hydroxyethylcellulose and a carboxymethylcellulose are especially included.

Preferably, the polysaccharide is selected from the group consisting of xanthan gums, gellan gums, pectins, alginates, succinoglycans, hydroxyethylcelluloses, carboxymethylcelluloses and mixtures thereof. Still preferably, the polysaccharide is an anionic polysaccharide. Thus, it traps cationic electrolytes, especially heavy metals that can be in the form of particles in a polluted atmosphere. The polysaccharide prevents their penetration into the skin. Preferably, the polysaccharide has a molecular weight greater than 106 Da, which allows it to form, after polymerization, a resistant film. The polysaccharide may be derived from the fermentation of bacteria on a plant substrate.

More preferably, the polysaccharide has a deacetylated branched chain, which advantageously improves the homogeneity, structure and strength of the formed film. Still preferably, the repeating unit of the polysaccharide is a tetrasaccharide composed of glucuronic acid, L-fructose and D-glucose, and is in particular the following: D-glucose OH The preferred polysaccharide is a gum-4 biosaccharide (CAS number 905593-86-4). It is an anionic polysaccharide which has a molecular weight of 2.106 Da. It is derived from the fermentation of yeasts, namely Saccharomyces cerevisiae, on a corn sorbitol substrate.

Preferably, the amount of polysaccharide of the emulsion is greater than or equal to 0.7%, greater than or equal to 0.8%, greater than or equal to 0.9%, preferably greater than or equal to 1.0%, and / or less than or equal to 5.0%, less than or equal to 4.5%, less than or equal to 4.0%, less than or equal to 3.5%, preferably less than or equal to 3.0%, in mass percentages on the basis of the emulsion. Below 0.7%, the polysaccharide does not prolong the diffusion time of the active principle principles. The polysaccharide before polymerization, and in particular when it is not yet incorporated in the emulsion, may be in the form of a 1% viscous solution in water, as a mass percentage on the basis of said solution . Preferably, the viscosity of the polysaccharide, prior to incorporation into the emulsion, is greater than 500cps and / or less than 1500cps. Advantageously, this viscosity range gives the emulsion a creamy and non-sticky texture, and makes it possible to spread the emulsion easily over large areas. The polysaccharide may be soluble in water, propylene, glycerol. It can be partially soluble in ethanol at 50 ° GL, ie it is possible to dissolve up to 40% or even up to 50% of the mass of said polysaccharide in ethanol. . It is immiscible with vegetable and mineral oils. Preferably, the polysaccharide is capable of being dissolved in water. Thus, the polysaccharide is distributed homogeneously around said micelles. Advantageously, this distribution promotes a regulated and prolonged diffusion of the active ingredients. Advantageously, the polysaccharide does not precipitate in the presence of salts. Moreover, the presence of salts makes it possible to increase the temperature from which the film formed is broken. Thus, an emulsion according to the invention may comprise salts, especially monovalent salts such as potassium chloride (ICI) and sodium chloride (NaCl). and preferably bivalent salts such as magnesium chloride (MgCl 2) and calcium chloride (CaCl 2). The polysaccharide is indeed more stable in the presence of bivalent salts than monovalent salts. In addition, the polysaccharide interacts with ethanol, isopropanol, propan-1-ol, propan-2-ol and glycols, in particular polyethylene glycol-8 (PEG-8), which improves its stability and its structure. Such compounds can therefore advantageously be incorporated into an emulsion according to the invention. Advantageously, the combination, in an emulsion according to the invention, of plant hydroglycolic extracts and the polysaccharide optimizes the texture of the emulsion. The water preferably represents more than 50%, more than 60%, preferably more than 70% and / or less than 90%, preferably less than 80% of the mass of an emulsion according to the invention. Beyond 90% water, an emulsion according to the invention has a too fluid texture, which flows to the surface of the skin and is long to dry. Below 10% water, the texture of an emulsion according to the invention is too thick to be properly vaporized and / or spread on the skin. The water may comprise compounds in dissolved form.

A dermo-cosmetic emulsion according to the invention also comprises micelles dispersed in water, said micelles containing at least one oil containing an active ingredient to be diffused through the skin, said micelles having a minimum size Dro greater than or equal to 0, 1 pm and a maximum size D90 less than or equal to 0.4 min.

The micelles may have a minimum size Dlo greater than or equal to 0.15 μm or greater than or equal to 0.20 μm and / or a maximum size of D90 less than or equal to 0.35 μm or less than or equal to 0.30 μm. The inventors have found that this size range is particularly effective for ensuring optimal diffusion of active ingredients. The decrease in the size of the micelles promotes the penetration of active ingredients into the skin.

The micelles contain at least one oil containing an active ingredient to diffuse through the skin. Preferably, the emulsion comprises at least one active ingredient of natural plant origin, and in particular a plant extract and / or an essential oil. Advantageously, unlike synthetically isolated active molecules, a natural plant extract may contain many active ingredients with different properties, which can act synergistically.

Preferably, at least one or all of the active ingredients are soluble or miscible in oil and are contained in the micelles dispersed in the emulsion. Advantageously, the effectiveness and the depth of their diffusion through the skin is improved. The emulsion may comprise a constituent preferably chosen from a soothing agent, an essential fatty acid, an antiseptic essential oil, a spinach caper extract, lactic acid, an insecticidal and / or insect repellent and / or antiparasitic oil, a anti-inflammatory agent, an antihistamine agent and mixtures thereof. Preferably, an emulsion according to the invention comprises a soothing agent, able to calm the manifestations of irritation of the skin and in particular the itching.

Its mass content is preferably greater than or equal to 0.3% and / or less than or equal to 3.3%, in percentages by weight on the basis of the emulsion. It can be chosen from all compounds of natural origin having a soothing property. It preferably comprises: more than 0.3%, and / or less than 0.8% of bisabolol and / or more than 0.3% and / or less than 0.5% of oryzanol and / or more than 1% and / or less than 2% laureth-9, that is polyoxyethylene lauryl ether. Bisabolol is both a soothing agent for irritations and a disinfectant. The oryzano [. is a soothing agent and has anti-inflammatory properties. Laureth-9 has an anesthetic effect.

Preferably, an emulsion according to the invention comprises essential fatty acids, the mass content of which is greater than or equal to 0.3% and / or less than or equal to 7%, in percentages by weight on the basis of the emulsion. They can be chosen from mono-saturated, poly-saturated, monounsaturated or polyunsaturated essential fatty acids, such as, for example, essential oils rich in omega-3 and omega-6 essential fatty acids. Essential fatty acids help repair the surface hydrolipidi film of the skin, which is a natural protective film and regulator of skin hydration. Due to its slightly acidic pH, the hydrolipidic film is a protective barrier against bacteria. The essential fatty acids of an emulsion according to the invention preferentially comprise: more than 0.3% and / or less than 2% of neem seed oil, for example azadirachta indica and / or more than 1%, and or less than 5% of hemp seed oil, for example cannabis sativa. In addition to its moisturizing and regenerating properties, neem seed oil has anti-fungal and antiviral properties. Hemp seed oil is chosen for its high content of polyunsaturated fatty acids. It comprises, in particular, as polyunsaturated fatty acids, omega-6 which contain linoleic acid and omega-3 which contain alpha-linolenic acid.

Preferably, an emulsion according to the invention comprises lactic acid, supplied in an amount sufficient to bring the pH of the emulsion to a value of between 6.8 and 7.2. Thus, the lactic acid content is preferably greater than 0.1% and / or less than 5% by weight percent based on the emulsion. Lactic acid allows a return to the acidic pH of a disturbed skin and also promotes the growth of saprophytic bacterial populations of commensal skin flora, for example lactobacilli.

Preferably, an emulsion according to the invention comprises a spinous caperous extract, for example capparis spinosa, the mass content of which may preferably be greater than or equal to 0.1% and / or preferably less than or equal to 0.4. %, in percentages by mass on the basis of the emulsion. Advantageously, the spiny caper has antihistaminic properties. In addition, it contains anti-oxidants which assist in the reconstruction of the surface hydrolipidic film of the skin. The spiny caper used in the invention is preferably obtained by a supercritical CO2 extraction process, which preserves the integrity of its active principles. An emulsion according to the invention may also comprise octyl dodecyl myristate. The total mass content of spiny caper and octyldodecyl myristate may be greater than or equal to 0.5% and / or less than or equal to 0.8%, in percentages by weight based on the emulsion.

Preferably, an emulsion according to the invention comprises antiseptic essential oil. Its mass content is preferably greater than or equal to 0.1% and / or less than or equal to 2.5%, in percentages by weight on the basis of the emulsion. Below 0.1%, the antiseptic effect of the essential oil is no longer sufficiently effective. The antiseptic essential oil preferably comprises: more than 0.5% and / or less than 1.5% of essential oil of cajeput, for example melaleuca cajuputi and / or more than 0.1% and / or less than 1% essential oil of tea tree leaves, for example jnelaleuca alternifolia.

Preferably, an emulsion according to the invention comprises at least one soothing agent and a spinous caper extract. Advantageously, and surprisingly, the combination of moiras with a soothing agent and a spinous caper extract makes it possible not to use dermo-corticosteroids to treat cutaneous disorders, such as, for example, utopian dermatitis and / or a pruritus, and thus avoids the many side effects associated with these dermo-corticosteroids.

Advantageously, all the constituents mentioned above retain their properties as a mixture in an emulsion according to the invention. They can be in dissolved form, in oil micelles or in water, or in the form of a liquid miscible in oil or water. Because it comprises water and oil, an emulsion according to the invention may advantageously simultaneously contain hydrophilic active principles and lipophilic active principles. Thus, an emulsion according to the invention preferably comprises, among its lipophilic active principles, essential oils, laureth-9, bisabolol, oryzanol, neem seed oil, and hydrophilic active ingredients, hemp seed oil. The effects on the skin of each of the active ingredients of the constituents of the invention are known. The overall effect of a composition obtained from different active ingredients is however not predictable. Indeed, the different active ingredients can interact with each other to achieve a particular result, for example because the known effect of an active ingredient can be modified. Side effects may also occur, for example allergic effects. All active ingredients known for transcutaneous use can be envisaged.

The above-mentioned mass contents have been determined so as to obtain optimum effectiveness of the emulsion. In one embodiment, an emulsion according to the invention does not comprise an active ingredient in an amount that makes it possible to obtain a therapeutic effect.

A dermo-cosmetic emulsion according to the invention may also comprise 5% to 1.5.5% of additives. By additive is meant in particular any usual cosmetic component that can be selected from antioxidants, preservatives, neutralizers, surfactants, sunscreens, sweeteners, surfactants, cosmetic stabilizers, pH adjusters, vitamins, moisturizers, anti-free radical agents, sequestering agents, hydrophilic active agents, lipophilic active agents, including waxes of animal, plant, mineral or synthetic origin, and mixtures thereof.

An emulsion according to the invention preferably comprises, in mass percentages on the basis of the emulsion: more than 70% of water, more than 1.0% and less than 3.0% of biosaccharide gum-4, more than 0 , 3% and less than 0.8% of bisabolol, more than 0.3% and less than 0.5% of oryzanol, more than 1% and less than 2% of laureth-9, more than 0.3% and less than 2% of neem seed oil, more than 1% and less than 5% of hemp seed oil, more than 0.5% and less than 1.5% of cajeput essential oil, more than 0.1% and less than 1% tea tree leaf essential oil, more than 0.5% and less than 0.8% thorny caper and octyldodecyl myristate, more than 0, 1% and less than 5% lactic acid.

According to a variant of the main embodiment, the invention proposes a method for manufacturing an oil-in-water dermo-cosmetic emulsion comprising the following steps: a) preparation of a base mixture comprising at least one oil which contains a. active ingredient to diffuse through the skin; b) mixing said base mixture with an emulsifier; c) adding, in the base mixture and / or in the emulsifier and / or in the mixture resulting from step b), a polysaccharide capable of forming, after polymerization, a film, the base mixture, the the emulsifier and the polysaccharide being chosen so as to obtain, after the mixing of said base mixture, said emulsifier and said polysaccharide, a dermo-cosmetic emulsion comprising micelles containing at least said oil, said micelles having a minimum size D1a greater than or equal to 0.1 μm and a maximum size D90 less than or equal to 0.4 μm.

Step c) is preferably subsequent to step b), the polysaccharide being added to the mixture resulting from step b).

An exemplary method is now described in detail. The mentioned temperature ranges and the order of introduction of the compounds used in this process are advantageously determined so as to guarantee the physicochemical integrity of the compounds. In step a), the base mixture may comprise a soothing agent, preferably chosen from bisabolol and / or oryzanol and / or laureth-9, and / or essential fatty acids, preferably from hemp seed oil, and / or a prickly caper extract. More preferably, to prepare the base mixture, oryzanol is solubilized in bisabolol, and / or laureth-9, and / or. hemp seed oil, and / or a spinach caper extract at a temperature above 40 ° C and below 50 ° C. Advantageously, a temperature greater than 40 ° C makes it possible to completely dissolve the oryzanol and a temperature of less than 50 ° C. and to preserve the physicochemical integrity of the components of the mixture.

The base mixture may comprise a stabilizing agent, for example sodium polyacrylate. Preferably, the stabilizing agent is hydrated by introducing it into water heated to a temperature above 50 ° C and below 70 ° C, before mixing said water containing said stabilizing agent with the base mixture. According to the invention, the composition of the base mixture is adjusted so as to obtain, after step c), an emulsion according to the invention. Conventionally, the emulsiomaant comprises water, an emollient, a thickener, a viscosity adjuster, an emulsifier, a humectant, a. conditioner. The emulsifier may in particular comprise diglycerin. In the presence of the emulsifier, the inventors have observed the existence of liquid crystals disposed at the interface between the water and the oil, on the surface of said micelles. These crystals advantageously stabilize the emulsion. In addition, they form a crystal lattice network between which water can be trapped. Advantageously, the inter-lamellar water increases the water retention potential of the skin. on which the emulsion is applied. The water retention is all the more important that the film formed by the polysaccharide retains micelles, and therefore surrounding liquid crystals, on the surface of the skin. The ability of the emulsion to moisturize the skin is thus improved. Preferably, the emulsifier is manufactured according to a cold manufacturing process, which advantageously makes it possible not to alter the active ingredients of natural origin that it is likely to contain. In step a), the emulsifier is mixed with at least one antiseptic essential oil, preferably chosen from the essential oil of cajeput and / or the essential oil of tea tree leaves.

In step b), the base mixture and the emulsifier are intimately mixed. More preferably in step b), the base mixture is at a temperature above 40 ° C and below 60 ° C when mixed with the emulsifier. Preferably, at the end of step b), neem seed oil is incorporated into the mixture. In step e), a polysaccharide capable of forming, after polymerization, a film is added to the base mixture and / or to the emulsifier and / or to the mixture resulting from step b).

Preferably, step e) is subsequent to step b), the polysaccharide being added to the mixture resulting from step b). More preferably, the mixture from step b) is at a temperature above 30 ° C and below 50 ° C when adding said polysaccharide. In step e), a preservative is incorporated, for example methyl hydroxyglycinate, preferably after the addition of the polysaccharide. In a subsequent optional step d), the mixture is brought to a temperature preferably greater than 15 ° C. and lower than 25 ° C., so as to obtain suitable temperature conditions for using a dermo-cosmetic emulsion according to US Pat. The invention then adds lactic acid so that the pH of the mixture is between 6.8 and 7.2. Advantageously, this pH value promotes the return to a normal pH of a skin to be treated. After complete cooling, an emulsion according to the invention is obtained. The invention thus relates to an emulsion obtained or obtainable with such a manufacturing process.

The invention also relates to a cosmetic skin treatment method comprising a step consisting of applying an emulsion according to the invention, in particular to the skin of an animal other than man. Preferably, an emulsion according to the invention is sprayed with a spray pump bottle or an aerosol container on an irritated area of the skin. Preferably during an application, a spray is sufficient to treat an injured area. An emulsion spray makes it possible to treat an area of 180 cm 2 of skin. It can be done as many sprays as there are injured areas to treat. The application is preferably renewed more than once a day and / or less than five times a day, but can be repeated as many times as necessary. An emulsion according to the invention may in particular be applied to areas usually subject to atopic dermatitis and / or pruritus, for example areas exposed to friction and / or wet, especially in the folds of the skin and / or at the level of the skin. joints of the limbs.

When applied to the skin, an emulsion according to the invention forms almost instantaneously a polymeric film comparable to a second skin. Advantageously, it is unnecessary to rub the treated area to penetrate the emulsion.

After polymerization, the polysaccharide forms a matrix network with a thickness less than 1 mm, less than 0.5 mm, less than 0.3 mm, less than 0.1 mm or even a substantially monomolecular network, that is to say a thickness equal to that of a molecule. This structure allows the skin to breathe, which advantageously limits the risk of infections. It is thus different from that of usual occlusive dressings which constitute a moist physiological medium conducive to the development of bacteria. Once applied to the skin, an emulsion according to the invention prevents the action of free radicals on the bristles and prevents the passage of ultraviolet radiation and dust.

The polysaccharide is preferably biocompatible, biodegradable and resorbs itself when applied to the skin. Advantageously, it is unnecessary to rinse after application of the emulsion on the skin. An emulsion according to the invention is thus different from compositions which form a mask, which is removed by peeling. When an emulsion according to the invention is applied to the skin, the diffusion of the active principles it contains is immediate and effective, probably due to the size of the micelles containing active ingredients. Advantageously, an emulsion according to the invention thus quickly relieves irritated and / or itchy skin, which in particular makes it possible to limit the risk of skin damage and associated infections. However, the film formed on the skin avoids too rapid diffusion of the active ingredients. An emulsion according to the invention thus allows both immediate diffusion and diffusion which is prolonged over time, in an efficient manner. In addition, film constitutes an effective and durable barrier against external aggressions. An emulsion according to the invention thus has a preventive action on the factors likely to aggravate skin irritation, such as pollution, dust, friction or scratching. In addition, the film provides a prolonged diffusion of active ingredients, which helps relieve the animal permanently and act effectively on the causes of irritation.

The invention also relates to the use of a dermo-cosmetic emulsion according to the invention as a medicament, in particular for the treatment of pruritus and / or utopic dermatitis.

A dermo-cosmetic emulsion according to the invention can be used to reduce the manifestations of discomfort of irritated skin, in particular redness, itching, burning and inflammation, tingling, tightness, dry skin. In particular, a dermo-cosmetic emulsion according to the invention is well suited to treat or prevent pruritus on atopic skin, and more specifically pruritus on skin with atopic dermatitis.

Finally, the invention relates to an animal other than the human whose at least part of the skin carries an emulsion according to the invention, or a film resulting from a polymerization of a polysaccharide of an emulsion according to the invention.

Example: Manufacture of an Emulsion According to the Invention The following example is presented by way of illustration of the invention and should not be interpreted as limiting the scope thereof.

In order to manufacture an emulsion according to this example, a manufacturing process comprising the following steps is used: a) Preparation of the base mixture and the emulsifier a. Preparation of a mixture To 1kg of hemp seed oil, 1kg of laureth-9, 0.8kg of octyldodecyl lyristate and thorny caper extract, 0.3kg of bisabolol and 0.3kg of oryzanol powder are mixed with stirring at 300 rpm. and heated to a temperature between 40 ° C and 50 ° C. After 60 minutes, the time required for perfect dissolution of the powder, heating and stirring are stopped. The mixture A thus obtained is in the form of a homogeneous and transparent liquid. h. Preparation of a mixture B 86 kg of water are introduced into a tank and are then heated to a temperature of between 50 ° C. and 70 ° C. 0.25 kg of sodium polyacrylate are then introduced into the tank. The mixture is stirred at 600 rpm for about 90 minutes until a lump free gel is obtained. The temperature of the mixture B thus prepared is maintained between 50 ° C. and 70 ° C.

Mixture A is introduced into the tank containing mixture B, then the whole is stirred at 600 rpm for 30 minutes. This gives a basic mixture. The temperature of the base mixture is decreased and maintained between 40 ° C and 60 ° C. h) Blend of the mixture of hase with the emulsifier 18kg of RESCONCEPTeCARE-2 are intimately mixed with 11 (g of essential oil of cajeput, 0,3kg of essential oil of leaves of tea tree and 0,8kg of neem seed oil, then introduced into the base mixture, the stirring is carried out at 300 rpm for 40 minutes, the temperature is then decreased and maintained between 30 ° C. and 50 ° C. c) Addition of the polysaccharide 1.0 2kg of biosaccharide gum-4 are incorporated in the mixture resulting from step b). Only then 0.7kg of sodium hydroxyglycinate is added. The whole is stirred at 300 rpm for 30 minutes. Finally, when the mixture resulting from stage c) is at a temperature of between 15 ° C. and 25 ° C., lactic acid is introduced in an amount adequate to obtain a pH of between 6.8 and 7, 2, with stirring at 200 rpm. Stirring is maintained for 30 minutes.

Of course, the present invention is not limited to the described embodiment provided by way of illustrative and non-limiting example. 20

Claims (1)

CLAIMS1 oil-in-water dermo-cosmetic emulsion comprising: micelles containing at least one oil containing an active ingredient to be diffused through the skin, said micelles having a minimum size D10 greater than or equal to 0.1 μm and a maximum size D90 less than or equal to 0.4 pm; water in which a polysaccharide is dissolved, said polysaccharide being capable of forming, after polymerization, a film, and representing more than 0.7% and less than 5% of the emulsion, in percentages by weight. Ulsion according to the preceding claim, wherein said active ingredient is selected from the group consisting of essential oils and plant extracts. An emulsion according to any one of the preceding claims, wherein said polysaccharide is selected from the group consisting of xanthan gums, gellan gums, pectins, alginates, succinoglycans, hydroxyethyl celluloses, carboxymethyl celluloses and mixtures thereof . An emulsion according to any one of the preceding claims, wherein said polysaccharide has a repeating unit of the formula: ## STR1 ## The emulsion according to any of the preceding claims, wherein the mass content of said polysaccharide is greater than or equal to equal to 1.0% and / or less than or equal to 3%, in mass percentages on the basis of the emulsion. An emulsion according to any one of the preceding claims comprising a soothing agent and a spinach caper extract. Emulsion according to any one of the preceding claims, comprising, in mass percentages on the basis of the emulsion: more than 0.3% and / or less than 3.3% of a soothing agent, and / or more of 0.3% and / or less than 7% of essential fatty acids, and / or more than 0.1% and / or less than 0.4% of a spinach caper extract, and / or more than 0% , 1% and / or less than 2.5% antiseptic essential oil. 8. Emulsion according to the preceding claim, comprising, in mass percentages on the basis of the emulsion: as a soothing agent o more than 0.3% and / or less than 0.8% of bisabolol and / or o more than 0, 3% and / or less than 0.5% r of oryzanol and / or o more than 1% and / or less than 2% of laureth-9, and / or ù as essential fatty acids o more than 0.3% and / or less than 2% neem seed oil and / or o more than 1% and / or less than 5% hemp seed oil, and / or ù as antiseptic essential oil o more than 0, 5% and / or less than 1.5% essential oil of cajeput and / or o more than 0.1% and / or less than 1% essential oil of tea tree leaves. An emulsion according to any one of the preceding claims, having greater than 0.1% and / or less than 5% lactic acid, in percentages by weight based on the emulsion. 10. Emulsion according to any one of the preceding claims, simultaneously containing hydrophilic active principles and lipophilic active ingredients. Emulsion according to any one of the preceding claims, comprising liquid crystals disposed on the surface of said micelles and forming a crystal lattice network between which water is trapped. An emulsion according to any of the preceding claims for treating or preventing pruritus on the skin of an animal other than humans. 13. A method of manufacturing an oil-in-water dermo-cosmetic emulsion comprising a step of mixing at least one oil which contains an active principle to be diffused through the skin, an emulsifier, water and a polysaccharide capable of forming, after polymerization, a film, the mixture being made and the emulsifier and the polysaccharide being chosen so as to obtain, after said mixing step, a dermo-cosmetic emulsion according to any one of the preceding claims . 14. An animal other than a human whose at least part of the skin is coated with an emulsion according to any one of claims 1 to 12, or a film resulting from a polymerization of a polysaccharide of an emulsion according to any one of claims 1 to 12. 15. Use of a dermo-cosmetic emulsion according to any one of claims 1 to 12 as a medicament, in particular for the treatment of pruritus and / or utopic dermatitis. 20 25