WO2024121509A1 - Cosmetic/dermatological composition comprising silk particles - Google Patents

Abstract

The invention relates to a composition (10), for example a cream or a milk, comprising silk particles (11), the silk particles (11) having a diameter of less than 10 µm. The silk particles (11) are preferably fibroin particles.

Description

Z DERMATOLOGICAL COSMETIC COMPOSITION COMPRISING SILK PARTICLES

TECHNICAL AREA

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

The invention relates in particular to a composition intended to be applied to the skin, a composition for use as a medicine, a composition for use in the treatment or prevention of skin diseases or even a cosmetic use of a composition for hydration of the skin for example.

The invention is particularly interesting since it makes it possible to treat skin disorders of microbial origin.

STATE OF PRIOR ART

Biofilms are films with the ability to adhere to virtually any surface, whether biotic or abiotic, including cutaneous surfaces (skin and mucous membranes), which can cause chronic infections, e.g. pimples, rash, inflammation, which are difficult to eradicate.

The biofilm consists of a mixture of microorganisms embedded in self-produced extracellular polymeric substances (EPS). EPS provides a structural scaffold to which other carbohydrates, proteins, nucleic acids, and lipids adhere. The presence of biofilms represents a serious problem in environmental, food and biomedical fields such as dermatology and cosmetics, because these architectures protect bacteria from hostile environments and prevent the effect of antimicrobial agents. The characteristics of exopolysaccharides differ between different bacteria and depend on growth conditions, environment and nutrient availability. In some forms of biofilm, mannose, galactose and glucose are the most abundant carbohydrates, followed by N-acetyl-glucosamine, galacturonic acid, arabinose, fucose, rhamnose and xylose, which are found in the composition of the biofilm matrix. Most exopolysaccharides are not biofilm specific, but their production increases following a stress response, such as production of colanic acid by Escherichia coli and the synthesis of alginates by Pseudomonas aeruginosa.

Biofilm formation and development consists of four different stages: (i) aggregation or attachment; (ii) adhesion of microbes; (iii) development and maturity of the biofilm; and (iv) biofilm aging, as described in the article by Kumar A, et al. (“Biofilms: Survival and defense strategy for pathogens”. Int. J. Med. Microbiol., 2017, 307: 481-489).

The aggregation or fixation stage is divided into a reversible and irreversible phase. Reversible adhesion begins when microorganisms come into contact with the target surface. During this event, certain weak interactions, including electrostatic Van Der Walls forces, and hydrophobic interactions between molecules present on the microbial cells and those present on the target surface are established. Subsequently, the irreversible adhesion phase takes place with the formation of covalent interactions and the initial production of exopolysaccharides (EPS). In the adhesion stage, the microcolonies formed are protected by extracellular polysaccharides or by cellular organelles, such as pili and fimbriae, which allow the bacterial cells to survive. During the third stage, the colony grows, acquiring a fungus-like architecture, and the cells undergo further adaptation to life in a biofilm. In particular, two properties are often associated with surface-attached bacteria: increased EPS synthesis and the development of antibiotic resistance. These characteristics appear to create a protective environment and make biofilms a stubborn health problem. Finally, in the last stage, the biofilm is able to release part of the colonies into the environment and the bacterial cells move to further colonize other surfaces under suitable conditions, thus entering another biofilm cycle. Each stage of the biofilm formation process depends on the microbial genera and species, characteristics of the attachment surface, environmental conditions and the physiological state of the microorganism.

Thus, the biofilm matrix protects bacteria from hostile environments. Biofilms are very difficult to treat. Most often high doses of antibiotics are required. However, such a solution is not sustainable since it contributes to the increase in bacterial resistance.

STATEMENT OF THE INVENTION

An aim of the present invention is to provide a composition which at least partly remedies the drawbacks of the prior art, and in particular, a composition having a natural active agent making it possible to act against the formation of the biofilm of skin bacteria such as Staphylococcus aureus. (S. aureus), responsible for skin atopy problems and Cutibacterium acnes (C. acnes), responsible for acne.

For this, the present invention provides a composition comprising a micronized silk powder. Micronized silk powder is formed from silk particles having a diameter of less than 10 μm. Advantageously, the composition according to the invention is suitable for inhibiting the formation of biofilm.

Advantageously, the silk particles are fibroin particles.

The invention fundamentally differs from the prior art by the use of micronized silk powder as active agent (or active principle) of the composition. Quite unexpectedly, it was observed that this composition acts against the formation of the biofilm of skin bacteria such as Staphylococcus aureus (5. aureus), responsible for skin atopy problems and Cutibacterium acnes (C. acnes), responsible acne.

This active agent, coming from natural sources, exhibits anti-biofilmic activity. While not bound by theory, it appears that silk particles may act at different stages of biofilm formation, on disparate molecular targets, and with diverse mechanisms of action. These include inhibition of biofilm formation and adhesion, downregulation of quorum-sensing factors, and disruption of preformed biofilm.

Preferably, the diameter of the silk particles is between 3 and 7 μm, for example 5 micrometers.

Advantageously, the composition comprises between 1 and 10% and more particularly between 2.5 and 5% by weight of silk particles. Advantageously, the composition further comprises a prebiotic associated with a postbiotic.

Advantageously, the prebiotic is a fructo-oligosaccharide and the post-biotic is an extract of Lactobacillus lactis.

The composition is a composition intended for use on the skin. The composition can be in the form of a cream, a milk or an ointment.

The composition is prepared from an emulsion, in particular an oil-in-water type emulsion.

Advantageously, the composition is in the form of a cream produced from an emulsion, in particular an oil-in-water emulsion, comprising an aqueous phase and an oily phase comprising the silk particles.

The invention also relates to a composition as defined above for its use as a medication, preferably a medication for topical use.

The invention also relates to a composition as defined above for its use in the treatment of skin atopy (atopic dermatitis) and acne or the prevention of skin atopy and acne.

The invention further relates to a composition as defined above for its use in inhibiting the formation of a biofilm of skin bacteria.

The invention also relates to a cosmetic (non-therapeutic) use of a composition as defined above for hydrating the skin or healing the skin.

The invention further relates to a non-therapeutic (cosmetic) use of a composition as previously defined for inhibiting the formation of a biofilm of skin bacteria.

The invention also relates to a method for inhibiting the formation of a biofilm of skin bacteria.

Advantageously, the skin bacteria biofilm may be a biofilm produced by Staphylococcus aureus and/or Cutibacterium acnes.

Finally, the invention relates to a method of treating or preventing skin atopy (atopic dermatitis) or acne. Advantageously, such a method of treating or preventing skin atopy (atopic dermatitis) or acne comprises a step of applying a therapeutically or cosmetically effective quantity of a composition as defined above to a suffering subject. atopic dermatitis or acne.

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.

BRIEF DESCRIPTION OF THE DRAWINGS

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 attached Figure 1 representing, schematically, a composition, according to a particular embodiment of the 'invention.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

Although this is in no way limiting, the invention particularly finds applications in the cosmetic (non-therapeutic) field and/or in the dermatological (therapeutic) field to address the cosmetic problems of atopic-prone skin and acne-prone skin.

The composition can be used on normal skin, atopic-prone skin or acne-prone skin.

The composition can be used to moisturize and/or soothe the skin.

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

The composition may be used for therapeutic use, or in a method of treatment or prevention.

In particular, the therapeutic treatment may concern skin suffering from atopic dermatitis and acne-prone skin. The composition makes it possible to slow down, or even inhibit, the growth of biofilms caused by the bacterial strains S. aureus and C. acnes, and can therefore be used for these purposes.

The composition is, for example, a cream, an ointment or a milk. It is made from an emulsion. It can be a water-in-oil emulsion or an oil-in-water emulsion. Preferably, the emulsion is an oil-in-water emulsion (i.e. the continuous phase is the aqueous phase and the internal phase is the oil phase).

Composition 10 includes silk particles 11 as an active agent (Figure 1). Preferably, the silk particles in the composition are fibroin particles.

The silk particles 11 have a diameter of less than 10 μm. The particles have a diameter greater than 0.1 pm. By diameter, we mean the diameter in the case of a spherical particle or the largest dimension, in the case of a non-spherical particle.

The silk particles 11 are preferably spherical or substantially spherical. They preferably have a diameter of between 3 and 7 μm, for example a diameter of 5 micrometers. By between 3 and 7 pm, we mean that terminals 3 and 7 are included.

Silk powder can be obtained by micronization of silk cocoons. The cocoons are advantageously previously cleaned in boiling distilled water in order to eliminate the sericin and then dried. The micronization step is carried out in a micronizer. The powder obtained (also called micronized silk powder) can be subjected to a sieving step before use.

Composition 10 comprises between 1 and 10% and more particularly between 2.5 and 5% by weight of silk particles 11.

Preferably, composition 10 further comprises a prebiotic and/or a postbiotic. Even more preferably, the composition comprises a prebiotic associated with a post-biotic.

By “prebiotic” we mean a food ingredient that beneficially affects the host. Prebiotics are, in particular, sugars, for example monosaccharides, disaccharides or oligosaccharides.

Advantageously, the prebiotic is a fructo-oligosaccharide.

By “postbiotic” is meant a metabolic product or by-product secreted or released by a probiotic organism and which has a positive biological activity on the host. Advantageously, the post-biotic is an extract of Lactobacillus lactis.

To make composition 10, an emulsion is prepared. For example, the emulsion is obtained according to the following steps: a) preparing a fatty phase, the fatty phase being advantageously heated to a temperature between 30°C and 100°C, for example 80°C, the fatty phase comprising 1 to 10%, for example 5% of micronized silk powder (as a percentage by weight in the final composition), and in particular of micronized fibroin powder, b) prepare an aqueous phase, the aqueous phase being advantageously heated to a temperature between between 30°C and 90°C, for example 80°C, c) mixing the fatty phase and the aqueous phase, whereby an emulsion is obtained.

For example, to obtain a moisturizing cream, during step a), the fatty phase may also comprise one or more of the following elements: ceteareth-2, ceteareth-21, oil (for example wheat germ oil and/or coconut oil), Octyl Palmitate.

Preferably, during step b), the aqueous phase further comprises one or more of the following elements: glycerin, hexylene glycol, fructo-oligosaccharides, Lactobacillus lactis extract, silk protein hydrolyzate, preservatives.

Step c) is carried out, for example with stirring, preferably at a temperature less than or equal to 40°C and greater than or equal to 20°C.

During step c), one or more of the following elements are added to the emulsion at a temperature, preferably below 40°C: water, phospholipids, sodium hyaluronate, tocopherol , vitamin A palmitate, ceramides 3.

For example, to obtain a cream or milk intended for acne-prone skin, during step a), the fatty phase also comprises one or more of the following elements: Glycerol Monostereate, Plum oil. Octyl Glucoside, cetostearyl alcohol.

Preferably, during step b), the aqueous phase further comprises one or more of the following elements: fructo-oligosaccharides, Lactobacillus lactis extract, Silk protein hydrolyzate, Glycerin, Hexylene glycol, Tamarind polysaccharides, Phytic Acid, Sodium Hyaluronate, Preservative, Fragrance. Step c) is carried out, for example with stirring, preferably at a temperature less than or equal to 40°C and greater than or equal to 20°C.

During step c), one or more of the following elements are added to the emulsion at a temperature, preferably below 40°C: tocopherol acetate, Pyridoxine, vitamin A palmitate, d-Panthenol, citric acid, zinc gluconate, trisodium citrate, water.

Illustrative and non-limiting examples

A fibroin powder micronized to 5 micrometers was manufactured (example 1). The anti-biofilm formation activity of this fibroin powder was used on two bacterial strains taken from samples after swabbing the facial skin of volunteers and selection of specific colonies (example 2).

This fibroin powder has also been formulated in the form of an emulsion in order to address the cosmetic problems of atopic-prone skin and acne-prone skin (examples 3 and 4).

Example 1: Obtaining 5 micrometer fibroin powder:

Firstly, a fibroin powder micronized at 5 micrometers was manufactured.

Silk cocoons from Société Séricyne S.A.S. (France), previously cleaned in boiling distilled water to eliminate sericin and dried, were micronized in a micronizer (HERBOLD SMF). Following this micronization, the powder obtained was sieved through an INOX sieve with a mesh size of 5 micrometers.

Example 2: Effects of 5 micron Fibroin Powder (PDF5) on the formation of the biofilm of S. aureus and C. acnes.

2-1) Bacterial strains and growth conditions:

S. aureus and C. acnes were used in this study. The strains of S. aureus and C. acnes were isolated from skin samples and were provided by the Bio-Ec laboratories (Longjumeau-France) after swabs from the skin's face. atopic humans (35 year old woman) and acne sufferers (18 year old boy). These people gave their informed consent.

These strains were cultured in tryptic soy broth (TSB; Difco Laboratories, USA) for 24 h at 37°C and stored at 80°C with 20% glycerol. For biofilm assay, strains were cultured in BST containing 0.25% glucose (D-(+)-Glucose; Sigma -Germany) to induce biofilm formation.

2-2) Measurement of the inhibitory effect on biofilm formation:

Biofilm inhibition by PDF5 was assessed using a crystal violet assay, as described in the article by Jung GH et al. (I. J. Microbiol. Biotechnol. 2017, Tl: 1942-1951).

To measure the inhibitory effect of PDF5 on the initial stages of biofilm formation, bacterial cultures were diluted to a final concentration of 1.0 x ^{10 5} CFU/ml and 50 µl were transferred to a multi-well plate. in polystyrene (96-well microtiter plate (SPL)) with PDF5 at 50 μl in a concentration range of 12.5 to 100 mg/ml (2.5% to 10% by weight) and incubated for 24 h at 37° vs. The control was prepared in BST without PDF5 for each strain.

The culture medium was removed and the wells were washed twice with distilled water to remove planktonic cells. The plates were incubated at 37°C for 15 min to dry them completely. Then, 100 μl of a 1% crystal violet solution was added to each well to stain the biofilm of attached bacteria. After 30 min, the wells were washed gently with tap water and then with distilled water. Then, a volume of 100 μl of dissolving solution (30% methanol and 10% acetic acid) was added to each well to dissolve the crystal violet, and the optical density (OD) was measured at 570 nm at l using a microplate reader (Emax, Molecular Devices, USA).

Biofilm formation rate (%) was calculated using the following equation:

Biofilm formation rate (%) = Treatment OD / Control OD x 100 where the Treatment OD and Control OD refer to the absorbance at 570 nm in each well with and without PDF5, respectively, after the addition of dissolving solution . The percentages of inhibition of biofilm formation of the two microbial cultures by fibroin powder at different concentrations are presented in the following table:

These results confirm that fibroin powder inhibits biofilm formation of both microbial cultures. The higher the concentration of fibroin powder, the more marked the effect.

Example 3: Soothing Moisturizing Cream intended for atopic-prone skin ^1st step: the oily phase is heated to 80°C. The fatty phase includes (in mass percentage):

Ceteareth-2: 3.5%

Ceteareth-21: 2 to 4%

Wheat germ oil: 3%

Octyl Palmitate: 8%

Coconut oil: 7%

Fibroin powder: 5% dispersed vigorously

^2nd step: the heated aqueous phase is heated to 80°C. The ingredients are added with stirring. The aqueous phase comprises (in mass percentage):

Glycerin: 7.0%

Hexylene glycol: 3.0%

Fructo-oligosaccharides (BIOECOLIA-SOLABIA): 2%

Lactobacillus lactis extract (LACTOPHYT-GREENTECH): 1%

Silk protein hydrolyzate (SOLLICE): 1%

Conservatives: qs

Water: qsp 100% The aqueous phase and the fatty phase are mixed to form an emulsion.

^3rd step: the following ingredients are mixed with stirring at 40°C then added to the emulsion at a temperature below 40°C (as a percentage by weight):

Water: 5%

Phospholipids: 0.5%

Sodium hyaluronate: 0.1%

Tocopherol: 0.05%

Vitamin A palmitate: 0.1%

Ceramides 3: 0.1%

Example 4: Cream and milk intended for acne-prone skin ^1st step: the fatty phase is heated to 80°C. The fatty phase includes (in mass percentage):

Glycerol Monostereate: 2%

Plum oil: 10%

Octyl Glucoside: 3%

Cetostearyl alcohol: 1%

Fibroin powder 5 microns: 2.5%

^2nd step: the aqueous phase is heated to 80°C. The ingredients are added with stirring. The aqueous phase comprises (in mass percentage):

Water qsp.100%

Fructo-oligosaccharides (BIOECOLIA-SOLABIA): 2%

Lactobacillus lactis extract (LACTOPHYT-GREENTECH): 1%

Silk protein hydrolyzate (SOLLICE): 1%

Glycerin: 7%

Hexylene glycol: 3.0%

Tamarind polysaccharides: 0.5%

Phytic Acid: 0.2%

Sodium hyaluronate: 0.1%

Perfume preservative: qsp.

The aqueous phase and the fatty phase are mixed to form an emulsion. gth step: the following ingredients are added to the emulsion, at a temperature below 40°C (in percentage by weight):

Tocopherol acetate: 0.1 to 1%

Pyridoxine: 0.01 to 0.05% Vitamin A palmitate: 0.01 to 1% d-Panthenol: 0.1 to 1%

Citric acid: 0.1 to 0.5%

Zinc gluconate: 0.1 to 1%

Trisodium citrate: 1 to 2.5% Water: 5%

Claims

1. Composition (10), for inhibiting the formation of biofilms, comprising silk particles (11), the silk particles (11) having a diameter less than 10 pm. 2. Composition according to claim 1, characterized in that the silk particles (11) are fibroin particles. 3. Composition according to one of the preceding claims, characterized in that the diameter of the silk particles (11) is between 3 and 7 pm, for example 5 micrometers. 4. Composition according to any one of the preceding claims, characterized in that the composition (10) comprises between 1 and 10% and more particularly between 2.5 and 5% by weight of silk particles (11). 5. Composition according to any one of the preceding claims, characterized in that the composition (10) further comprises a prebiotic associated with a post-biotic. 6. Composition according to the preceding claim, characterized in that the prebiotic is a fructo-oligosaccharide and the post-biotic is an extract of Lactobacillus lactis. 7. Composition according to any one of the preceding claims, characterized in that the composition (10) is in the form of a cream produced from an emulsion, in particular an oil-in-water emulsion, comprising an aqueous phase and an oily phase comprising the silk particles (11). 8. Composition (10) according to any one of claims 1 to 7 for its use as a medication, preferably a medication for topical use. 9. Composition (10) according to any one of claims 1 to 7 for its use in the treatment of skin atopy or acne or in the prevention of skin atopy or acne. 10. Composition (10) according to any one of claims 1 to 7 for its use in inhibiting the formation of a biofilm of skin bacteria. 11. Cosmetic (non-therapeutic) use of a composition (10) according to any one of claims 1 to 7 for hydrating the skin or healing the skin. 12. Cosmetic (non-therapeutic) use of a composition (10) according to any one of claims 1 to 7 for inhibiting the formation of a biofilm of skin bacteria.