FR3142885A1 - COSMETIC/DERMATOLOGICAL EMULSION - Google Patents

Abstract

The invention relates to an oil-in-water emulsion comprising a lipophilic phase and a hydrophilic phase. The emulsion is free of emulsifier. The hydrophilic phase comprises between 1 and 10% by weight of insoluble protein particles. The lipophilic phase represents between 10 and 50% of the total volume of the emulsion. Figure for abstract: 1B

Description

COSMETIC/DERMATOLOGICAL EMULSION

The present invention relates to the general field of products for topical uses.

The invention relates in particular to an emulsion, an emulsion for use as a medicine, an emulsion for use in the treatment or prevention of dermatological disorders or even a cosmetic use of such a composition for hydrating the skin for example. .

STATE OF PRIOR ART

Emulsions are mixtures, macroscopically homogeneous but microscopically heterogeneous, comprising an aqueous or hydrophilic phase and an oily or lipophilic phase. The two liquids being immiscible, a dispersion of one liquid into fine droplets in the other liquid is obtained. The liquid in the form of droplets being the dispersed phase, also called discontinuous phase or internal phase, the other liquid being the hydrophilic dispersing phase, also called continuous phase or external phase.

Stable oil-in-water emulsions are commonly used in compositions for topical use in cosmetic and/or pharmaceutical and/or dermatological products.

These emulsions are generally high percentage emulsions in hydrophilic continuous phase, that is to say that the aqueous phase can represent more than 80% by total volume of the emulsion.

However, to be stable, these emulsions require the addition of synthetic emulsifiers (also called synthetic emulsifiers), such as cetyl dimethicone polyol, stearyl alcohol or cetyl glucoside. However, the presence of synthetic products in emulsions intended for topical application can cause irritant or even allergic reactions when they come into contact with the skin, particularly when they come into contact with sensitive skin.

An aim of the present invention is to propose a composition which at least partly remedies the drawbacks of the prior art, and in particular, a stable composition which meets the desires of users by being devoid of emulsifier, in particular emulsifiers of syntheses, and can in particular be used in the treatment of skin disorders or as a cosmetic product for dermatological use.

For this, the present invention provides an oil-in-water emulsion comprising a lipophilic phase and a hydrophilic phase. The emulsion according to the invention is devoid of emulsifier (also called emulsifier). The hydrophilic phase comprises between 1 and 10% by weight of insoluble protein particles, for example 10% by weight of insoluble protein particles as essential active agents. The lipophilic phase represents between 10 and 50% of the total volume of the emulsion, for example 30% of the total volume of the emulsion.

The invention fundamentally differs from the prior art by the presence of insoluble protein particles (in particular silk protein particles). Thus, the emulsion has a high percentage of lipophilic internal phase. The emulsion is stable even if it is devoid of emulsifier.

Advantageously, the insoluble proteins are fibroin particles, the fibroin particles having a diameter of between 0.1 to 10 micrometers, for example 5 micrometers.

Advantageously, the hydrophilic phase also comprises between 1 and 5% by weight of soluble protein particles.

Advantageously, the soluble proteins come from plant protein hydrolysates (for example soy protein hydrolysates and/or rice protein hydrolysates) and/or the soluble proteins come from silk protein hydrolysates (such as sericin). .

Advantageously, the hydrophilic phase comprises peptides of biosynthetic or microbiological origin.

Advantageously, the hydrophilic phase further comprises one or more of the following elements: betaine, glycine, nisin and NaCl.

The invention also relates to an emulsion as described above for its use as a medication, preferably a medication for topical use.

The invention also relates to an emulsion as described above for its use in the treatment or prevention of skin disorders (inflammation of the skin for example).

The invention also relates to a non-therapeutic (cosmetic) use of an emulsion as described above for hydrating the skin or reducing/removing wrinkles from the skin.

The invention also relates to a use of an emulsion as described above as a vehicle for the release of one or more active ingredients. In particular, it is a use as vehicles for the percutaneous release of one or more active ingredients.

Other characteristics and advantages of the invention will emerge from the additional description which follows.

It goes without saying that this additional description is given only by way of illustration of the object of the invention and should in no way be interpreted as a limitation of this object.

The present invention will be better understood on reading the description of exemplary embodiments given for purely indicative purposes and in no way limiting with reference to the appended figures for which:

There is a photographic shot of a skin explant 3 hours after the elimination of part of the lipids by a chemical treatment without application of any cream, example given for comparison,

There represents the photograph of a skin explant 3 hours after the elimination of part of the lipids by a chemical treatment and to which an emulsion according to a particular embodiment of the invention has been applied,

There represents the photograph of an immunostaining of filaggrin, of a skin explant 3 hours after the elimination of part of the lipids by a chemical treatment and to which no emulsion has been applied,

There represents the photograph of an immunostaining of filaggrin, of a skin explant 3 hours after the elimination of part of the lipids by a chemical treatment and on which an emulsion according to a particular embodiment of the invention has been applied,

There represents the photograph of an immunostaining of transglutaminase, of a skin explant 3 hours after the elimination of part of the lipids by a chemical treatment and to which no emulsion has been applied,

There represents the photograph of an immunostaining of transglutaminase, of a skin explant 3 hours after the elimination of part of the lipids by a chemical treatment and on which an emulsion according to a particular embodiment of the invention has been applied,

There represents the photograph of LEKTI immunostaining, of a skin explant 3 hours after the elimination of part of the lipids by a chemical treatment and to which no emulsion has been applied,

There represents the photograph of an immunostaining of LEKTI, of a skin explant 3 hours after the elimination of part of the lipids by a chemical treatment and to which an emulsion according to a particular embodiment of the invention has been applied .

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

Although this is in no way limiting, the invention particularly finds applications in the non-therapeutic field (cosmetics) and/or in the therapeutic field.

The emulsion can, in particular, be used in the treatment of cosmetic and/or dermatological skin disorders. In particular, the emulsion has moisturizing, healing and/or anti-inflammatory properties.

In particular, this composition for cosmetic use can be used to prevent the symptoms of skin aging and stimulate skin healing.

In particular, cosmetic/therapeutic treatment may concern acne scars, stretch marks.

We will first give some definitions.

By “the lipophilic phase represents approximately 30% of the total volume of the emulsion” we mean that the lipophilic phase represents between 27 to 33% of the total volume of the emulsion, preferably 30%.

By “isotonic aqueous phase” is meant an aqueous or hydrophilic phase containing a quantity of dissolved solutes equal to that of the cytoplasm of the epithelial cells, i.e. 0.15 molar.

The term “insoluble proteins” means any hydrophobic proteins such as fibroin particles (for example calibrated between 0.5 and 10 μm, and more particularly 5 microns), wool particles or keratin protein particles.

The term “soluble proteins” means all hydrophilic proteins such as proteins derived from enzymatic or chemical hydrolysates of plant proteins such as hydrolysates of rice or soy plant proteins.

The term “peptide of biosynthetic or microbiological origin” means any peptide synthesized by microorganisms having antibacterial, anti-inflammatory and/or healing properties which may be in particular Nisin or Lactobacillus bacteriocins.

By “amino acid” we mean all amino acids and their derivatives or a mixture of these, in a free form, in particular glycine, betaine from beet extract.

The term “glycerides” means all glycerides such as monoglycerides, diglycerides or triglycerides or a mixture of these, in particular vegetable oils, butters, for example sweet almond oil or Shea butter.

The term “squalane” means all squalanes resulting from the hydrogenation of squalene, particularly from plant squalene.

By “fatty acid ester” we mean all esters derived from vegetable oil, particularly safflower, olive and sunflower oil.

By “sterols” we mean all sterols, in particular all sterols from plants such as beta-sitosterol from pine bark.

The term “lipopeptides” means all lipopeptides such as lipomonopeptides, lipo-dipeptides, lipo-tripeptides or a mixture of these in particular.

By “active ingredients” we mean all fat-soluble molecules having cosmetic, curative or preventive properties such as caffeine, retinol (Vitamin A).

By “diameter” we mean either the diameter of a particle in the case of a spherical particle or the largest dimension of a particle in the case of a non-spherical particle.

Furthermore, by “between X and Y”, we mean that the terminals X and Y are included.

We will now describe the emulsion according to the invention in more detail.

The emulsion is a stable emulsion over time and does not include an emulsifier and in particular it does not include a synthetic emulsifier.

The emulsion is an oil-in-water type emulsion. The internal phase is a lipophilic phase and the continuous phase is the hydrophilic phase (or aqueous phase).

The lipophilic phase of the emulsion represents between 10 and 50% of the total volume of the emulsion, preferably between 20% and 40% of the total volume of the emulsion. For example, the lipophilic phase represents approximately 30% of the total volume of the emulsion.

The hydrophilic phase comprises at least between 1% and 10% by weight, preferably between 5% and 10% by weight, for example 10 grams of an insoluble protein powder as active principle (or active agent) per 100 grams of final product. Particulate, the powder is a fibroin protein powder. Fibroin is one of the two proteins in the silk cocoon.

Preferably, the particles of the fibroin powder have a diameter of between 0.1 and 10 μm, preferably between 3 and 7 μm, for example 5 micrometers.

The particles are preferably spherical or substantially spherical.

Preferably, the hydrophilic phase of the emulsion further comprises one or more of the following elements: soluble proteins, peptides of biosynthetic or microbiological origin, amino acids, mineral salts.

The hydrophilic phase advantageously comprises between 5% and 20% by weight, for example 15% by weight, of a mixture of proteins, insoluble proteins, soluble proteins, peptides and amino acids.

The elements of the mixture can be distributed according to the following quantities (in percentage by mass):

− Insoluble proteins of 1 to 10%

− Soluble proteins of 1 to 5%

− Peptides of biosynthetic or microbiological origin from 0.001 to 5%

− Amino acids of 1 to 5%

− Mineral salts of 0.1 to 0.9%.

Preferably, the lipophilic internal phase of the emulsion comprises one or more of the following: glycerides, squalane, octyldodecyl PCA, aminopropanediol ester, fatty acid esters, sterols, lipopeptides.

For example, the lipophilic internal phase of the emulsion comprises (in mass percentage):

− Glycerides of 0.1 to 5%

− Squalane from 0.1 to 4%

− Octyldodecyl PCA from 0.1 to 3%

− Aminopropanediol ester from 0.01 to 1%

− Fatty acid esters of 0.01 to 1%

− Sterols of 0.01 to 0.1%

− Lipopeptides from 0.1 to 1%

Advantageously, the emulsions without emulsifier according to the invention can be used as vehicles for the percutaneous release of one or more active ingredients, in particular fat-soluble active ingredients.

The process for manufacturing oil-in-water emulsions includes a step during which the lipophilic phase is mixed with the hydrophilic phase. Preferably, the lipophilic phase is introduced into the hydrophilic phase. The mixture is advantageously carried out with stirring and at a temperature between 25° and 90°, for example at a temperature of 80°C.

Illustrative and non-limiting examples:

The following example is an example, given for illustrative and non-limiting purposes, of an emulsion without an oil-in-water emulsifier.

First, the lipophilic phase was prepared. In order to obtain 300g of lipophilic phase, the following reagents were mixed at 80°C (in mass percentage):

- Sweet almond oil 37%

- Shea Butter 5%

- Phytosqualane 35%

- Octyldodecyl PCA 16.10%

- Ester of Aminopropanediol and safflower fatty acids 3.75%

- Beta-sitosterol 0.15%

- Lipo-tripeptide 3%

After mixing the reagents with stirring, the homogeneous lipophilic phase was left at 80°C before introduction into the hydrophilic phase.

Secondly, 700g of isotonic hydrophilic phase were prepared. In this phase the fraction by weight of insoluble, soluble proteins, peptides and added amino acids represents 15% by mass. The following reagents were mixed at 80°C (in mass percentage):

- Water 83.71%

- NaCl 0.29%

- Betaine 1.17%

- Glycine 1%

- Rice protein hydrolyzate 3.82%

- Nisin 0.01%

- Calibrated fibroin powder 5 microns 10%

Into this vigorously stirred phase and, still under stirring, the lipophilic phase was slowly poured, itself kept under stirring.

The emulsion, without emulsifier, thus formed is used for carrying out ex-vivo tests on human skin explants maintained in survival to measure its hydration, anti-inflammatory and healing properties, with a view to its use for the treatment of cosmetic or dermatological skin disorders.

has. Hydration properties:

The hydration properties of cream according to the above formulation were evaluated by:

- histological expertise of the general morphology of the skin.

- Filaggrin immunostaining

- Immunostaining of membrane transglutaminase (TGM)

- LEKTI immunostaining

Preparation of explants:

27 explants with a diameter of approximately 10 mm were prepared from an abdominoplasty of a woman with her informed consent (reference P942-AB20. Lonjumeau Hospital). The explants were placed in survival mode in BEM (BIO-EC’s Explants Medium -Sigma) medium at 37°C in a humid atmosphere, enriched with 5% CO2.

The explants were separated into 3 groups of 9 explants.

Delipidation:

Delipidation was carried out to alter the barrier function of the stratum corneum on groups 2 and 3. Delipidation was carried out using a mixture of organic solvents (ether/acetone 50/50) (1 ml-Fluka) which was applied to the explants for 2 minutes. The mixture was then aspirated and the skin wiped with a cotton ball.

Application of the cream:

Immediately after delipidation, the cream was applied to the explants of group 3 at a rate of 4 mg per explant and spread using a spatula to obtain a uniform layer. On days D1, D2 and D3, the cream was once again applied to the explants of group 3 at a rate of 2 mg per explant and spread evenly using a spatula. The following table represents the distribution of explants and the treatments undergone: Band Number explants Delipidation Applying the cream 1 9 2 9 Yes 3 9 Yes Yes

Specimens :

Samples were taken to allow histological observations and immunostaining to be carried out with a view to determining the hydration properties of the cream comprising 90% of the emulsion.

On D0+3 hours, D1 and D4, 3 explants from each group were taken and cut in two.

One half was fixed with buffered formalin and the other half was frozen at –80°C.

Histological treatments:

After 24 hours of fixation in buffered formalin, the samples were dehydrated and impregnated in paraffin using a Leica TP 1020 dehydration machine according to the MO-H-149 operating mode.

The samples were blocked according to the MO-H-153 procedure using a Leica EG embedding station.

Sections of 5 μm were made according to the MO-H-173 procedure using a Minot type microtome, Leica RM 2125 and mounted on Superfrost® histological glass slides.

Frozen samples were cut at 7 μm in a Leica CM 3050 cryostat.

The sections were glued to Superfrost® Plus silanized histological glass slides to carry out immunostaining.

The microscopic observations were carried out by optical microscopy, using a Leica Orthoplan or DMLB type microscope. The shots were taken with an Olympus DP72 camera and Cell^D software.

Examination of general morphology:

The general morphology was examined on paraffin sections stained with Masson's trichrome variant of Goldner, according to the MO-H-157 procedure.

The general morphology was assessed by microscopic examination, mainly on the structure of the stratum corneum.

Immunomarkings:

All immunostaining was carried out using an immunostaining machine (marketed by Dako, AutostainerPlus) following the manufacturer's instructions and the marking was evaluated by fluorescence microscopic examination.

Filaggrin immunostaining:

The proteolysis of filaggrin produces amino acids, important components of NMF (marketed by Natural Moisturizing Factor) forming the intercorneocytic cementum responsible for the barrier function of the stratum corneum.

Filaggrin was marked on formalin paraffin sections, with an anti-filaggrin monoclonal antibody, clone AKH1, (marketed by Santa Cruz under the reference sc-66192), made on mice at 1/3200 for 1 hour at 20°C with a system biotin/streptavidin amplifier (marketed by Sigma) and revealed in FITC (marketed by Sigma)

The nuclei were counterstained with propidium iodide (marketed by Sigma).

Immunostaining of the transglutaminase membrane (TGM) :

TGM is an enzyme involved in the formation of the horny envelopes of the stratum corneum.

The TGM was marked on frozen sections using an anti-TGM monoclonal antibody, clone B.C1, (marketed by Harbor BioProducts, under the reference 621), made on mice, diluted 1/100 for 1 night at 20°C with a Vectastain RTU Universal VECTOR avidin/biotin amplifier system (marketed by Sigma) and revealed in FITC (sigma). The nuclei were counterstained with propidium iodide (marketed by Sigma).

LEKTI immunostaining:

LEKTI is a serine protease inhibitor that regulates stratum corneum desquamation.

LEKTI was marked on formalin paraffin sections using an anti-LEKTI monoclonal antibody, clone 1C11G6, (marketed by Santa Cruz, under the reference 32330), made on mice, diluted 1/100 for 24 hours at TA with a Vectastain RTU Universal VECTOR avidin/biotin amplifier system (marketed by Sigma) and revealed in FITC (sigma). The nuclei were counterstained with propidium iodide (marketed by Sigma).

Results :

Comparisons between photographs of the control groups (Figures 1A, 2A, 3A and 4A) and the treated group (Figures 1B, 2B, 3B and 4B) were made.

The comparison between Figures 1A and 1B shows in particular a better laminated stratum corneum for the explant of the .

Furthermore, there is a good restructuring activity of the skin barrier for the explant having benefited from the application of emulsion, without emulsifier, characterized by:

- Total inhibition of the drop in filaggrin expression induced by delipidation as shown in .

- Total inhibition of the drop in TGM expression induced by delipidation as shown in .

- Partial inhibition of the drop in LEKTI expression induced by delipidation as shown in .

Observations of samples at 4 days confirm the results described above.

Conclusion on hydration properties:

Reading these results, the emulsion without emulsifier, according to the invention has good hydration properties and can be used for the treatment of cosmetic or dermatological skin disorders.

b. Anti-inflammatory properties:

When LPS (lipopolysaccharide) is applied to human skin an inflammatory reaction is triggered.

From then on, the cells secrete cytokines, notably interleukins IL1α and IL8, and the cause of tumor necrosis TNFα in the extracellular environment.

These cytokines can then be quantified in order to evaluate the anti-inflammatory properties of products.

Preparation of explants:

18 explants with a diameter of approximately 10 mm (± 1 mm) were prepared from an abdominoplasty of a woman (reference P946-AB-Hopital Longjumeau). The explants were placed in survival mode in BEM (BIOEC’s Explants Medium-Sigma) medium at 37°C in a humid atmosphere, enriched with 5% CO2.

The explants were separated into 3 groups of 6 explants.

Application of products:

LPS at a rate of 2 mg/cm² was applied to groups 2 and 3.

On group 3, emulsion was applied and spread evenly using a spatula,

On day D1, 2 mL of the culture medium was renewed for all explants.

On days D1 and D2, a disc of filter paper impregnated with 30 μL of LPS (at 60,000 U/mg) was applied, for 1 hour, to the surface of the explants of the 2 previously treated groups.

The following table represents the distribution of explants and the treatments undergone: Band Number of explants LPS treatment Applying the cream 1 6 2 6 Yes 3 6 Yes Yes

On day D2 evening, 2ml of each of the culture media were taken, to quantify the concentration of IL1α, IL8 and TNFα.

Dosages:

The concentrations of IL1α, IL8 and TNFα were determined by an absorbance assay according to methods known to those skilled in the art.

All absorbances were measured using a microplate reader marketed under the reference Tecan Infinite M200 Pro, associated with Magellan software according to the manufacturer's instructions.

An average of the concentration of IL1α, IL8 and TNFα in pg.mL ^-1 was determined for each group.

IL1α dosage:

The concentration of IL1α in the culture media was determined using an EIA kit assay kit (marketed by Cayman, under the reference 583301) according to the manufacturer's instructions.

The results of the IL1α dosage in pg.mL ^-1 are as follows:

- group 1: Average 14.7

- group 2: average 15.5

- group 3: average 9.8

Dosage of IL8:

The concentration of IL-8 in the culture media was determined using an assay kit (RayBiotech, ref ELH-IL8-001) according to the manufacturer's instructions.

The results of the IL8 dosage in pg.mL ^-1 are as follows:

- group 1: Average 8.34

- group 2: average 30.20

- group 3: average 14.66

Dosage of TNFα:

The concentration of TNFα in the culture media was determined using an EIA kit assay kit (Cayman, ref. 589201) according to the manufacturer's instructions.

The results of the TNFα dosage in pg.mL ^-1 :

- group 1: Average 6.0

- group 2: average 23.1

- group 3: average 11.2

Results :

Under the operating conditions described above, after 2 days of treatment and by comparing group 2 (LPS only) and group 3 (LPS + Emulsion) it was shown that the emulsion according to the invention induced:

- a 37% reduction in IL1α

- a 51% reduction in IL8

- a 51% reduction in TNFα

Conclusion of the study on anti-inflammatory properties :

Reading these results, the emulsion, without emulsifier, according to the invention has good anti-inflammatory properties and can therefore be used for the treatment of cosmetic or dermatological skin disorders.

vs. Healing properties:

Healing properties are one of the other interesting properties of cosmetic and/or pharmaceutical and/or dermatological products for their uses in the treatment of cosmetic or dermatological skin disorders.

These properties were evaluated using a comparison between the effects of the emulsion, without emulsifier, according to the invention and the effects of a commercial cream (marketed under the name Cicalfate) known for its healing effects, applied on skin explants showing lesions due to UVB irradiation.

This comparison was carried out on the bases:

- histological expertise of the general morphology of the skin

- Immunostaining of fibronectin

- Immunostaining of β4 integrin

Preparation of explants:

27 explants of approximately 12 mm in diameter were prepared from an abdominoplasty of a woman with informed consent (reference P943-AB39- Longjumeau Hospital).

The explants were placed in survival medium in BEM (BIO-EC's Explants Medium-sigma) at 37°C in a humid atmosphere, enriched with 5% CO ₂ .

The explants were separated into 3 groups of 9 explants.

Realization of lesions due to irradiation:

All explants were irradiated at their center with a UVB dose of 10 J/cm².

Application of products:

On days D0, D1, D3, D5, D7 and D8, the emulsion according to the invention and commercial healing cream were applied respectively to the explants of groups 2 and 3 topically at a rate of 2 mg/cm² .

The culture medium was renewed by half (1 mL) on days 2, 4, 6 and 8.

Specimens :

On days D0, D2, and D9, 3 explants from each batch were taken and cut in half.

One part was fixed in a buffered formalin solution and the ^2nd part was frozen at –80°C.

Histological treatments:

The histological treatments were identical to the treatments received by the explants during the study on the hydration properties of the emulsion according to the invention (as described previously).

Examination of general morphology:

The general morphology was examined on days D0, D2 and D9 on paraffin sections stained with Masson's trichrome variant of Goldner, according to the MO-H-157 procedure.

General morphology was assessed by microscopic examination.

Immunomarkings:

All immunostaining was carried out using an immunostaining machine (Dako, AutostainerPlus) following the manufacturer's instructions and the marking was evaluated by fluorescence microscopic examination.

Fibronectin immunostaining:

Fibronectin plays a role in cell migration, and in the adhesion of cells to each other and the extracellular matrix, its presence is a witness to a cellular healing process.

Fibronectin was marked on days D0 and D2 on frozen sections, with a monoclonal anti-fibronectin antibody, clone TV-1, made on mice from Chemicon (marketed under the reference MAB 88904), at 1/50 for 1 hour at room temperature with a biotin/streptavidin amplifier system (marketed by Sigma) revealed in FITC (marketed by Sigma).

The nuclei were counterstained with propidium iodide (marketed by Sigma).

Immunostaining of β4 integrin:

β4 integrin is a transmembrane protein which allows cells to adhere to each other; its presence is another indicator of a healing process.

The β4 integrin was marked on days D0 and D9 on frozen sections, with a monoclonal anti-integrin β4 antibody clone 3 E1 (CD104), made on mice from Chemicon (marketed under the reference MAB 1964), at 1/600 scale. for 1 hour at room temperature with a biotin/streptavidin amplifier system (marketed by Sigma) revealed in FITC (marketed by Sigma).

The nuclei were counterstained with propidium iodide (marketed by Sigma).

Results :

Comparisons were made between photographs of the group of irradiated explants having received the emulsion according to the invention and the group of irradiated explants having received the commercial Cicalfate cream.

These comparisons show a similar presence of fibronectin and β4 integrin whatever the treatment received.

Conclusion on healing properties:

Reading these results, the emulsion according to the invention exhibits healing activity and can be used for the treatment of cosmetic or dermatological skin disorders.

Claims (8)

Oil-in-water emulsion comprising a lipophilic phase and a hydrophilic phase, characterized in that:
- the emulsion is free of emulsifier,
- the hydrophilic phase comprises between 1 and 10% by weight of insoluble protein particles,
- the lipophilic phase represents between 10% and 50% of the total volume of the emulsion. Emulsion according to claim 1, characterized in that the insoluble proteins are fibroin particles, the fibroin particles having a diameter between 0.1 to 10 micrometers. Emulsion according to one of the preceding claims, characterized in that the hydrophilic phase comprises between 1 and 5% by weight of soluble protein particles. Emulsion according to the preceding claim, characterized in that the soluble proteins come from hydrolysates of plant proteins, for example hydrolysates of soy or rice proteins, or in that the soluble proteins come from hydrolysates of silk proteins such as sericin. Emulsion according to one of the preceding claims, characterized in that the hydrophilic phase comprises peptides of biosynthetic or microbiological origin. Emulsion according to one of the preceding claims, characterized in that the hydrophilic phase further comprises one or more of the following elements: betaine, glycine, nisin and NaCl. Emulsion according to any one of claims 1 to 6 for its use as a medicine, preferably a medicine for topical use. Emulsion according to any one of claims 1 to 6 for its use in the treatment or prevention of skin disorders, for example inflammation of the skin.