Composition comprising chitosan and specific nanometer surface-treated inorganic pigments

Abstract

The present invention relates to a cosmetic composition comprising, in a physiologically acceptable aqueous medium, a) natural chitosan having a molecular weight strictly greater than 3000 daltons and present in an amount of at least 0.01% by mass of the total mass of the composition, and this amount being strictly less than 15% by mass, and b) at least one surface-treated inorganic pigment having a size of 100 nm or less. The present invention also relates to a method for cosmeticizing and / or caring for the skin and / or skin appendages, wherein the composition according to the present invention is applied to the skin and / or skin appendages.

Description

Technical Field

[0001] The present invention relates to a cosmetic composition comprising, in a physiologically acceptable aqueous medium, a) a natural chitosan having a molecular weight strictly greater than 3000 daltons and at least 0.01% by weight relative to the total weight of the composition, this amount being strictly less than 15% by weight, and b) at least one surface-treated inorganic pigment having a size of 100 nm or less. The present invention also relates to a method of cosmetically treating and / or caring for the skin and / or skin appendages, in which the composition according to the invention is applied to the skin and / or skin appendages.

[0002]

Background Art

[0003] Furthermore, it is often desired to obtain a composition with good covering power.

[0004] For this reason, formulators seek raw materials and / or systems that make it possible to obtain a fluid (i.e., flowing) composition whose deposit is covering, homogeneous and durable (i.e., having good resistance), and in particular having good resistance to water.

[0005]

[0006] ​Furthermore, the formulation of environmentally friendly liquid formulations, whose design and development take environmental challenges into consideration, is becoming a major concern in helping to address global challenges.

[0007] Therefore, in order to address these environmental challenges, it is essential to present more sustainable compositions, and / or preparation methods, and / or components.

[0008] In this context, it is particularly important to develop novel cosmetic compositions with a better carbon footprint by promoting the use of renewable raw materials and / or raw materials with a good wilderness quality index and / or naturally derived raw materials, more specifically plant-derived raw materials, while reducing the use of petrochemical compounds. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] WO03068824 [Non-patent literature]

[0010] [Non-Patent Document 1] Van de Hulst, HC, "Light Scattering by Small Particles," Chapters 9 and 10, Wiley, New York, 1957. [Non-Patent Document 2] M. Pissavini et al., International Journal of Cosmetic Science, 40, pp. 263-268 (2018) [Overview of the Initiative]

[0011] The object of the present invention is to provide an aqueous cosmetic composition that has good cosmetic properties, particularly in terms of covering power and homogeneity, as well as good resistance, especially to water.

[0012] After application, these compositions leave a coating and homogeneous film-forming deposit that has good resistance to abrasion. The formed film is adhesive and cohesive and has enhanced resistance to water.

[0013] Furthermore, surface treatment of inorganic pigments having a size of 100 nm or less can enhance the ultraviolet protection index of the resulting composition.

[0014] Furthermore, these compositions contain sustainable ingredients and therefore enable the addressing of environmental challenges.

[0015] Therefore, the present invention relates to a cosmetic composition particularly for skincare, for the application and / or care of the skin and / or lips, in a physiologically acceptable aqueous medium, a) Natural chitosan having a molecular weight of exactly greater than 3000 daltons in an amount of at least 0.01% by mass relative to the total mass of the composition, wherein this amount is strictly less than 15% by mass, and b) At least one surface-treated inorganic pigment having a size of 100 nm or less This relates to a composition containing the following:

[0016] "Physiologically acceptable" refers to a medium that is compatible with keratinic substances.

[0017] The present invention also relates to a method for cosmeticizing and / or caring for the skin and / or skin appendages, wherein a composition according to the present invention is applied to the skin and / or skin appendages.

[0018] Preferably, the compositions according to the present invention are substantially free of (meth)acrylic polymers. Preferably, the compositions according to the present invention are substantially free of silicones.

[0019] "Substantially free of (meth)acrylic polymer" means that the composition contains less than 1% by mass, preferably less than 0.5% by mass, preferably less than 0.3% by mass, preferably less than 0.1% by mass of (meth)acrylic polymer based on the total mass of the composition. Preferably, the composition contains no (meth)acrylic polymer at all. "(Meth)acrylic polymer" means a polymer containing at least one acrylic acid monomer or at least one methacrylic acid monomer.

[0020] "Substantially free of silicone" means that the composition contains less than 1% by mass, preferably less than 0.5% by mass, preferably less than 0.3% by mass, preferably less than 0.1% by mass of silicone based on the total mass of the composition. Preferably, the composition contains no silicone at all. "Silicone" means any silicone compound.

[0021] Chitosan The composition according to the invention contains at least 0.01% by mass, based on the total mass of the composition, of at least one natural chitosan having a molecular weight strictly greater than 3000 daltons (3 kDa) (1 Da = 1 g / mol).

[0022] The amount of natural chitosan is strictly less than 15% by mass based on the total mass of the composition.

[0023] Preferably, the natural chitosan has a molecular weight of 10 kDa or more, preferably 15 kDa or more, preferably 20 kDa or more. Preferably, the natural chitosan has a molecular weight between 10 kDa and 2 MDa, preferably between 15 kDa and 1.5 MDa, preferably between 20 kDa and 300 kDa, preferably between 20 kDa and 200 kDa.

[0024] Chitosan is not widely found in nature. Chitosan has only been reported in the exoskeletons of certain insects such as the queen termite, and in the cell walls of certain classes of fungi, namely zygomycetes.

[0025] Chitosan is obtained by the deacetylation of chitin. Chitin is a polysaccharide composed of several N-acetyl-D-glucosamine units interconnected by β-(1,4) type bonds.

[0026] The ideal chemical structure of chitosan is a chain of β-D-glucosamine monomers linked by glycosidic (1→4) bonds.

[0027] According to the present invention, "chitosan" means any copolymer formed by N-acetyl-D-glucosamine and D-glucosamine constituent units, wherein the degree of acetylation is less than 90%. Chitosan consists of glucosamine sugar units (deacetylated units) and N-acetyl-D-glucosamine units (acetylated units) interconnected by β(1,4) type bonds, and represents a poly(N-acetyl-D-glucosamine)-poly(D-glucosamine) type polymer.

[0028] Preferably, the degree of acetylation of chitosan is 80% or less, preferably 70% or less, preferably 60% or less, preferably 50% or less, preferably 35% or less, preferably 25% or less, and preferably 15% or less.

[0029] The degree of acetylation is the percentage of acetylated units relative to the total number of units, and can be determined by Fourier transform infrared spectroscopy (FTIR) or titration using a strong base.

[0030] The chitosan of the present invention is preferably a polysaccharide prepared from a fungal source. In particular, the chitosan is extracted and purified from a safe and abundant food-grade or biotechnology-grade fungal source such as mushroom (Agaricus bisporus) or black mold (Aspergillus niger).

[0031] The chitosan of the present invention is preferably derived from the mycelium of an ascomycete-type fungus, particularly Aspergillus oryzae and / or Basidiomycete fungus, particularly Lentinula edodes (shiitake mushroom) and / or button mushroom. Preferably, the fungus is Aspergillus oryzae.

[0032] The chitosan may be of GMO origin, but is preferably of non-GMO origin.

[0033] The chitosan according to the present invention is natural, that is, unmodified. In particular, the chitosan according to the present invention has not undergone any chemical modification.

[0034] One method for preparing chitosan is described in application WO03068824.

[0035] Preferably, the chitosan used in this invention is in powder form. In particular, it is sold by Kitozyme under the names Kiosmetine or Kionutrime.

[0036] Chitosan is preferably present in an amount ranging from 0.01% to 14% by mass, preferably 0.1% to 14% by mass, preferably 0.1% to 12% by mass, preferably 0.2% to 7% by mass, and preferably 0.25% to 5% by mass, relative to the total mass of the composition.

[0037] Nanometer surface-treated inorganic pigments The composition according to the present invention comprises at least one surface-treated inorganic pigment, wherein the pigment has a size of 100 nm or less ("nanometer surface-treated inorganic pigment").

[0038] The term "pigment" means white or colored inorganic particles that are insoluble in aqueous solutions and are intended to color a composition and / or the resulting deposits.

[0039] The treated pigment may be present in the composition in an amount ranging from 1 to 70% by mass, preferably 1 to 60% by mass, preferably 1% to 50% by mass, preferably 3% to 45% by mass, preferably 4% to 30% by mass, preferably 6% to 20% by mass, and preferably 6% to 15% by mass, based on the total mass of the composition.

[0040] Preferably, the mass ratio between the nanometer surface-treated inorganic pigment and chitosan (i.e., the pigment:chitosan mass ratio) is greater than 1, preferably between 1 and 30. Preferably, the mass ratio is between 1 and 25, preferably between 5 and 20.

[0041] Inorganic pigments "Inorganic pigment" means any pigment that is consistent with the definition in the chapter on inorganic pigments in Ullmann's Encyclopedia.

[0042] The size of inorganic pigments that can be used within the scope of the present invention is in nanometer units, i.e., 100 nm or less. According to a particular embodiment of the present invention, the pigment has a size characterized by D

[50] less than 100 nm, preferably less than 50 nm, preferably between 5 and 40 nm, and preferably between 10 and 30 nm.

[0043] The size is measured by static light scattering using a Master Sizer 3000® particle size analyzer, commercially available from Malvern, which allows for the determination of the particle size distribution for all particles over a wide range, from 0.01 μm to 1000 μm. This data is processed based on classical Mie scattering theory. This theory is best suited to size distributions ranging from less than a micron to several microns, and makes it possible to determine the "effective" diameter of the particles. This theory is described in detail in Chapters 9 and 10 of the book "Light Scattering by Small Particles" by Van de Hulst, HC, Wiley, New York, 1957.

[0044] D

[50] represents the maximum size of 50% of the particle by volume.

[0045] In this invention, any inorganic pigment having a size in the nanometer range can be used.

[0046] Inorganic pigments that can be used in the present invention include titanium dioxide, iron oxide (black, yellow, or red), zirconium oxide or cerium oxide, zinc oxide or chromium oxide, manganese violet, ultramarine blue, chromium hydrate and iron blue, aluminum powder and copper powder, and other metal powders.

[0047] Preferably, the inorganic pigment is titanium dioxide, more specifically.

[0048] Furthermore, if their size is in the nanometer range, we can also mention pigments that have optical effects different from those of conventional simple hue effects (e.g., monochrome pigments), such as nacres.

[0049] The term "pearlescent pigment" should be understood to mean iridescent or non-iridescent colored particles of any shape, particularly those produced in the shells of certain mollusks, or otherwise synthesized, that exhibit a color effect through optical interference.

[0050] The pearlescent pigment can be selected from pearlescent pigments such as titanium mica coated with iron oxide, titanium mica coated with bismuth oxychloride, titanium mica coated with chromium oxide, titanium mica coated with organic dyes, and bismuth oxychloride-based pearlescent pigments. The pearlescent pigment may also include mica particles on which at least two continuous layers of metal oxides and / or organic dyes overlap on their surface. Examples of pearlescent pigments include natural mica coated with titanium oxide, iron oxide, natural pigments, or bismuth oxychloride. More specifically, the pearlescent pigment may have yellow, crimson, red, bronze, orange, brown, and / or copper-colored hues or luster.

[0051] Among the pigments that can be used in accordance with the present invention, those that have optical effects different from the conventional simple hue effect, that is, the unified and stable effect produced by conventional dyes, such as monochrome pigments, can be mentioned.

[0052] For the purposes of this invention, "stable" means that there is no effect of color fluctuation depending on the viewing angle or in response to temperature changes.

[0053] Surface treatment agent The surface treatment agent according to the present invention is a hydrophobic agent. The surface treatment agent is preferably selected from fatty acids, metal salts, and mixtures thereof.

[0054] fatty acid "Fatty acid" refers to a carboxylic acid having an aliphatic chain containing 8 to 30 carbon atoms, preferably 12 to 24 carbon atoms, and more preferably 16 to 18 carbon atoms. Fatty acids may be liquid or non-liquid.

[0055] Liquid fatty acids are defined as those found at room temperature (25°C) and atmospheric pressure (760 mmHg), i.e., 1.013.10 5 Pa) refers to fatty acids that are in liquid form.

[0056] The fatty acid according to the present invention may be saturated or unsaturated.

[0057] Fatty acids suitable for carrying out the present invention are more specifically selected from linear or branched, saturated or unsaturated acids containing 8 to 30 carbon atoms.

[0058] Preferably, the fatty acid is selected from stearic acid, palmitic acid, palmitoleic acid, linoleic acid, caprylic acid, myristic acid, lauric acid, behenic acid, and isostearic acid.

[0059] metal salts The metal salt is preferably a hydroxide, such as an alkali metal hydroxide such as aluminum hydroxide, sodium, or potassium, or an alkaline earth metal hydroxide such as magnesium.

[0060] Preferably, the metal salt is aluminum hydroxide.

[0061] Preferably, the surface treatment agent according to the present invention is a mixture of a fatty acid and a metal salt, preferably a mixture of stearic acid and aluminum hydroxide.

[0062] Preferably, the nanometer surface-treated inorganic pigment according to the present invention is nanometer titanium dioxide treated with aluminum hydroxide and stearic acid, for example, sold by Teika Co., Ltd. under the name fine particle titanium dioxide MT-100TV.

[0063] Physiologically acceptable aqueous media The composition according to the present invention comprises a physiologically acceptable aqueous medium, the medium comprising water.

[0064] The water used may be sterilized demineralized water and / or floral water such as rose water, cornflower water, chamomile water or linden water, and / or spring mineral water or natural mineral water.

[0065] The composition preferably contains at least 5% by mass, preferably at least 10% by mass, preferably at least 20% by mass, preferably at least 30% by mass, and preferably at least 40% by mass of water relative to the total mass of the composition.

[0066] The composition preferably contains 5% to 95% by mass, more preferably 10% to 85%, even more preferably 20% to 80%, even more preferably 25% to 70%, even more preferably 28% to 60%, and even more preferably 30% to 50% water based on the total mass of the composition.

[0067] The aqueous phase may also contain at least one organic solvent that is miscible in water at 25°C.

[0068] Preferably, the water-miscible organic solvent is selected from alcohols, polyols, and mixtures thereof.

[0069] Among alcohols, C1~C 10 More preferably, C1 to C5 alcohols can be cited, such as ethanol, isopropanol, propanol, and butanol.

[0070] The polyol is preferably selected from polyols having 2 to 20 carbon atoms, more preferably 2 to 6 carbon atoms, such as glycerol, diglycerol, propylene glycol, isoprene glycol, dipropylene glycol, butylene glycol, hexylene glycol, 1,2-propanediol, 1,3-propanediol, pentylene glycol, polyethylene glycol having 2 to 200 ethylene oxide units, and mixtures thereof.

[0071] The composition may contain 0.1% to 25% by mass, more preferably 0.5% to 20% by mass, and even more preferably 0.9% to 15% by mass, of a water-miscible organic solvent based on the total mass of the composition.

[0072] Alpha hydroxy acids (AHAs) The composition according to the present invention may contain at least one AHA.

[0073] According to the present invention, an alpha hydroxy acid refers to a carboxylic acid having at least one hydroxyl functional group occupying the alpha position (the carbon adjacent to the carboxylic acid functional group) of the acid. In the final composition, this acid may be presented in the form of a free acid and / or one of its associated salts (particularly a salt with an organic base or alkali), depending on the final pH imposed on the composition.

[0074] Alpha-hydroxy acids (AHAs) are selected from, for example, lactic acid, citric acid, methyllactic acid, glucuronic acid, glycolic acid, pyruvate, 2-hydroxybutanoic acid, 2-hydroxypentanoic acid, 2-hydroxyhexanoic acid, 2-hydroxyheptanoic acid, 2-hydroxyoctanoic acid, 2-hydroxynonanoic acid, 2-hydroxydecanoic acid, 2-hydroxyundecanoic acid, 2-hydroxydodecanoic acid, 2-hydroxytetradecanoic acid, 2-hydroxyhexadecanoic acid, 2-hydroxyoctadecanoic acid, 2-hydroxytetracosanoic acid, 2-hydroxyeicosanoic acid; mandelic acid; phenyllactic acid; gluconic acid; galacturonic acid; alloylitic acid; ribonic acid; tartaric acid; tartaric acid; malic acid; fumaric acid; their salts and mixtures thereof.

[0075] According to a preferred embodiment, the alpha hydroxy acid is selected from lactic acid, citric acid, malic acid, tartaric acid, and salts thereof. More specifically, the alpha hydroxy acid is selected from lactic acid, citric acid, salts thereof, and mixtures thereof.

[0076] Alpha hydroxy acids may be present in amounts ranging from 0.001 to 10% by mass, 0.005 to 5% by mass, preferably 0.01 to 3% by mass, relative to the total mass of the composition.

[0077] surfactant The composition may contain at least one surfactant. The surfactant is preferably selected from anionic, cationic, nonionic, amphoteric, and amphoteric surfactants. Preferably, the surfactant is a) Nonionic surfactants, particularly those with an HLB of 8 to 25°C or higher, used alone or in mixtures. Examples include esters of fatty acids and polyglycerols, esters of fatty acids and polyethylene glycol, alkyl C8-C30 (poly)glycosides, or mixtures thereof. In particular, nonionic surfactants may be esters of fatty acids containing 10 to 18 carbon atoms and esters of polyglycerols containing 2 to 10 glycerol units. In preferred embodiments of the present invention, the fatty acid ester is polyglyceryl monolaurate containing 12 carbon atoms and 10 glycerol units, i.e., polyglyceryl-10 monolaurate (available from Dr. Straetmans under the trade name DERMOFEEL G10 L). The fatty acid ester may also be polyglyceryl-2 monooleate (available from Taiyo Kagaku Co., Ltd. under the trade name Sunsoft Q-17D(G)-C), or polyglyceryl-4 monocaprate or PG-4 caprate (available from Evonik Goldschmidt under the trade name Tegosoft PC 41). b) Anionic surfactants, e.g.: Polyoxyethylene-derived fatty acid salts, and those derived particularly from alkali salts, and mixtures thereof; Phosphate esters such as "Oleth-10 Phosphate DEA" (Crodafos N 10N, CRODA) or monocetyl dihydrogen phosphate (Amphisol K, Givaudan) and their salts; Sulfosuccinates such as "Disodium PEG-5 citrate lauryl sulfosuccinate" and "Disodium ricinoleamido MEA sulfosuccinate"; Alkyl ether sulfates such as sodium lauryl ether sulfate; Isethionate salt; Acyl glutamates such as "Hydrogenated disodium taro glutamate" (AMISOFT HS-21 R®, sold by Ajinomoto Co., Inc.) and sodium stearoyl glutamate (AMISOFT HS-11 PF®, sold by Ajinomoto Co., Inc.) and mixtures thereof; Soybean derivatives such as potassium soybean fatty acid; Citrates, for example, glyceryl stearate citrate (Axol C 62 Pellets, Degussa); Proline derivatives, such as sodium palmitoylproline (Sepicalm VG, Seppic), or a mixture of sodium palmitoylsarcosinate, magnesium palmitoylglutamate, palmitic acid, and palmitoylproline (Sepifeel One, Seppic); Lactates, such as sodium stearoyl lactate (Akoline SL, Karlshamns AB); Sarcosinates, such as sodium palmitoyl sarcosinate (Nikkol sarcosinate PN) or a 75 / 25 mixture of stearoyl sarcosine and myristoyl sarcosine (Crodasin SM, Croda); Sulfonates, for example, sodium C14-17 alkyl-sec-sulfonate (Hostapur SAS 60, Clariant); Glycinates, for example, sodium cocoyl glycinate (Amilite GCS-12, Ajinomoto Co., Inc.); C16-C30 fatty acid salts, especially those derived from amines, such as triethanolamine stearate and / or amino-2-methyl-2-propanediol-1,3-stearate; c) Amphoteric surfactants, such as N-acyl amino acids like N-alkyl-aminoacetates, disodium cocoamphodiacetate, and amine oxides like stearamine oxide, or silicone surfactants such as PEG-7 dimethicone copolyol phosphate, for example, sold by Phoenix Chemical under the trade name PECOSIL PS 100 (registered trademark); and mixtures thereof They will be selected from among them.

[0078] pH of the composition The composition according to the present invention has a pH of 7 or less, preferably 6.5 or less, and preferably 6.3 or less. Advantageously, the pH of the composition is between 3 and 6.3, preferably between 4 and 6.3.

[0079] Preferably, the cosmetic composition according to the present invention comprises at least one base and / or at least one acid. The base and acid according to the present invention are known in the field of cosmetics and have been used conventionally.

[0080] Bases and / or acids are used, in particular, to adjust the final pH of the composition between 3 and 6.3.

[0081] The acid could be, for example, citric acid.

[0082] The base can be selected from inorganic bases such as alkali metal hydroxides, sodium hydroxide, and potassium hydroxide.

[0083] Preferably, the base of the composition is an alkali metal hydroxide, preferably sodium hydroxide or potassium hydroxide.

[0084] The composition according to the present invention may contain at least one base in an active substance content ranging from 0.5% to 10% by mass, particularly 1% to 5% by mass, and preferably 1% to 4% by mass, relative to the total mass of the composition.

[0085] The composition according to the present invention can be obtained conventionally by those skilled in the art.

[0086] The present invention also relates to a method for cosmeticizing and / or caring for the skin and / or skin appendages, wherein a composition according to the present invention is applied to the skin and / or skin appendages.

[0087] The following examples allow for a better understanding of the present invention, but are not limiting in any way. The raw materials are referred to by their chemical name or INCl name. The amounts shown are, unless otherwise specified, as mass % (% w / w) of the raw materials relative to the total mass of the composition. [Examples]

[0088] (Example 1: Preparation of a composition according to the present invention and comparison with a comparative composition) Composition A and comparative composition B according to the present invention were prepared by mixing the components from Table 1.

[0089] Composition A according to the present invention contains TiO2 surface-treated with aluminum hydroxide and stearic acid.

[0090] Comparative composition B does not contain chitosan.

[0091] Composition A according to the present invention has a good carbon footprint, in particular by promoting the use of renewable raw materials and / or raw materials having a good naturalness index and / or natural origin, more specifically plant-derived raw materials.

[0092] The results are shown in Table 1.

[0093] [Table 1]

[0094] The formulation was manufactured according to the same method as described below: Lactic acid and chitosan were mixed using a VMI rotor stator until the chitosan was completely dissolved. Glycerol and polyglyceryl-10 laurate were added with gentle stirring. TiO2 was then gradually added and the mixture was kept stirring for 20 minutes.

[0095] evaluation: Visual evaluation: 24 hours after production, the sample was observed to detect phase separation of the system.

[0096] Resistance: To evaluate resistance to drying, water, and oil friction, 30 μl of the formulation was placed on a 5 × 5 cm black plate. 2 The material was applied by lightly drawing circles across the entire surface, followed by five back-and-forth motions with a finger. The applied material was allowed to dry in the open air for 3 hours. Then, it was subjected to various frictional stresses: - Dry friction: Each deposit was rubbed with 15 back-and-forth movements using a finger; - Water friction: After water was applied, each object was rubbed 15 times using a finger in a back-and-forth motion; - Water friction + dry cloth friction: Each attached substance was rubbed around 15 times with a finger, and then wiped with a dry cloth. - Oil (octyldodecanol) friction + dry cloth friction: Each adhering substance was rubbed around 15 times with a finger, and then wiped with a dry cloth.

[0097] result: Visual evaluation: The sample does not show phase separation. However, chitosan allows for better stabilization of the TiO2 dispersion.

[0098] Resistance: Resistance evaluations of deposits subjected to various stresses all show a clear difference between samples containing chitosan and those without. Deposits containing chitosan remain undamaged after stressing, while those without chitosan deteriorate significantly.

[0099] All results are summarized in the table below.

[0100] [Table 2]

[0101] Comparative formulation B, which does not contain chitosan, exhibits rapid phase separation and shows dewetted TiO2 on its surface, which forms a potentially inhalable powder cloud.

[0102] (Example 2: SPF evaluation of the composition according to the present invention and comparison with a comparative composition) The objective is to compare the in vitro UV protection index (SPF) of the aqueous formulation according to the present invention with that of a comparative oily formulation having the same amount of TiO2.

[0103] The two formulations tested were prepared as described in Example 1.

[0104] [Table 3]

[0105] In vitro SPF evaluation Filter effectiveness evaluation protocol In vitro: The UV protection factor (SPF) is determined based on the initial absorbance, following the "in vitro" method described by M. Pissavini et al. in the International Journal of Cosmetic Science, 40, pp. 263-268 (2018).

[0106] The in vitro UVA protection index (UVAPF) of UV protection products against UVA irradiation is mathematically calculated using an in vitro spectral model based on the ISO 24443:2012(Fr) protocol.

[0107] Each composition is applied to six PMMA substrate plates in the form of a homogeneous and uniform deposit at a concentration of 1 mg / cm². Each composition is then applied to three plates designated HD6 (molded granular plates) and three plates designated SB6 (sand-blasted granular plates) using an automated robot with regular and uniform movements. The plates are weighed before and after application. After applying to the six plates, they are placed in a Thermo-Masters in the dark at 25°C for 30 minutes. Measurements are performed using a Labsphere UV-1000S spectrophotometer. Nine measurements are taken for each plate, and then the SPF and UVAPF values ​​of the measured compositions are analyzed using an Excel spreadsheet.

[0108] [Table 4]

[0109] The results show that the formulation according to the present invention exhibits a 46.4% increase in SPF in vitro.

[0110] Conclusion: The composition according to the present invention makes it possible to enhance the SPF compared to a comparative oily composition containing the same amount of TiO2.

[0111] (Example 3: Comparison between the composition according to the present invention and a comparative composition containing nanometer TiO2 without surface treatment) The two formulations tested were prepared as described in Example 1.

[0112] [Table 5]

[0113] Evaluation and results: The resistance evaluation of the adhering substances (dry friction, water + dry cloth friction, and oil + dry cloth friction) was measured according to the same protocol as in Example 1.

[0114] The results are as follows:

[0115] [Table 6]

[0116] Conclusion: In the formulation of the present invention, using nano-TiO2 with a lower mass (8.2% by mass) compared to the comparative formulation (10% by mass nano-TiO2) improves drying and water friction for the surface treatment of TiO2 according to the present invention.

[0117] The comparative formulation shows no resistance to either dry or wet friction.

[0118] In vitro SPF evaluation In vitro SPF was evaluated according to the same protocol as in Example 2.

[0119] The results are as follows:

[0120] [Table 7]

[0121] Conclusion: The results show a 78% increase in SPF for the formulation according to the present invention in vitro.

[0122] The comparative formulation allows for higher filter penetration in UVAPF.

Claims

1. A cosmetic composition, particularly for the makeup and / or care of the skin and / or lips, in a physiologically acceptable aqueous medium, a) Natural chitosan having a molecular weight of exactly greater than 3000 daltons in an amount of at least 0.01% by mass relative to the total mass of the composition, wherein this amount is strictly less than 15% by mass, and b) At least one surface-treated inorganic pigment having a size of 100 nm or less A composition containing the following:

2. The composition according to claim 1, wherein the natural chitosan has a molecular weight of 10 kDa or more, preferably 15 kDa or more, preferably 20 kDa or more, and preferably the natural chitosan has a molecular weight between 10 kDa and 2 MDa, preferably between 15 kDa and 1.5 MDa, preferably between 20 kDa and 300 kDa, and preferably between 20 kDa and 200 kDa.

3. The composition according to claim 1 or 2, wherein the natural chitosan has a degree of acetylation of 80% or less, preferably 70% or less, preferably 60% or less, preferably 50% or less, preferably 35% or less, preferably 25% or less, and preferably 15% or less.

4. The composition according to any one of claims 1 to 3, wherein the natural chitosan is a polysaccharide prepared from a fungal source preferably derived from ascomycete fungi, particularly Aspergillus oryzae and / or basidiomycetes, particularly shiitake and / or button mushroom mycelium, and preferably the fungus is Aspergillus oryzae.

5. The composition according to any one of claims 1 to 4, wherein natural chitosan is present in an amount ranging from 0.01% to 14% by mass, preferably 0.1% to 14% by mass, preferably 0.1% to 12% by mass, preferably 0.2% to 7% by mass, and preferably 0.25% to 5% by mass, based on the total mass of the composition.

6. The composition according to any one of claims 1 to 5, comprising 1% to 70% by mass, preferably 1% to 60% by mass, preferably 1% to 50% by mass, preferably 3% to 45% by mass, preferably 4% to 30% by mass, preferably 6% to 20% by mass, and preferably 6% to 15% by mass, based on the mass of the composition.

7. The composition according to any one of claims 1 to 6, wherein the inorganic pigment is titanium dioxide.

8. The composition according to any one of claims 1 to 7, wherein the inorganic pigment has a size characterized by D[50] less than 100 nm, preferably less than 50 nm, preferably between 5 and 40 nm, preferably between 10 and 30 nm, where D[50] represents the maximum size of 50% of the particles by volume.

9. The composition according to any one of claims 1 to 8, wherein the pigment is treated with a hydrophobic surface treatment agent preferably selected from fatty acids, metal salts, and mixtures thereof, wherein the surface treatment agent is preferably a mixture of fatty acids and metal salts, preferably a mixture of stearic acid and aluminum hydroxide.

10. The composition according to any one of claims 1 to 9, wherein the surface treatment pigment is titanium dioxide treated with aluminum hydroxide and stearic acid.

11. The composition according to any one of claims 1 to 10, wherein a physiologically acceptable aqueous medium is at least 5% by mass, preferably at least 10% by mass, preferably at least 20% by mass, preferably at least 30% by mass, preferably at least 40% by mass, based on the total mass of the composition; preferably 5% to 95% by mass, more preferably 10% to 85%, even more preferably 20% to 80%, even more preferably 25% to 70%, even more preferably 28% to 60%, and even more preferably 30% to 50% of water based on the total mass of the composition; and optionally comprising at least one organic solvent miscible in water at 25°C, selected from alcohols, polyols, and mixtures thereof.

12. The composition according to any one of claims 1 to 11, preferably comprising lactic acid, citric acid, methyllactic acid, glucuronic acid, glycolic acid, pyruvic acid, 2-hydroxybutanoic acid, 2-hydroxypentanoic acid, 2-hydroxyhexanoic acid, 2-hydroxyheptanoic acid, 2-hydroxyoctanoic acid, 2-hydroxynonanoic acid, 2-hydroxydecanoic acid, 2-hydroxyundecanoic acid, 2-hydroxydodecanoic acid, 2-hydroxytetradecanoic acid, 2-hydroxyhexadecanoic acid, 2-hydroxyoctadecanoic acid, 2-hydroxytetracosanoic acid, 2-hydroxyeicosanoic acid; mandelic acid; phenyllactic acid; gluconic acid; galacturonic acid; aloylitic acid; ribonic acid; tartaric acid; tartaric acid; malic acid; fumaric acid; salts thereof and mixtures thereof, comprising at least one alpha hydroxy acid.

13. The composition according to any one of claims 1 to 12, having a pH of 7 or less, preferably 6.5 or less, preferably 6.3 or less, preferably between 3 and 6.3, and preferably between 4 and 6.

3.

14. A composition according to any one of claims 1 to 13, which is substantially free of (meth)acrylic polymer and / or silicone; preferably contains less than 1% by mass, preferably less than 0.5% by mass, preferably less than 0.3% by mass, preferably less than 0.1% by mass of (meth)acrylic polymer based on the total mass of the composition, preferably free of (meth)acrylic polymer; preferably contains less than 1% by mass, preferably less than 0.5% by mass, preferably less than 0.3% by mass, preferably less than 0.1% by mass of silicone based on the total mass of the composition, preferably free of silicone.

15. The composition according to any one of claims 1 to 14, characterized in that the mass ratio between the nanometer surface-treated inorganic pigment and chitosan (i.e., pigment:chitosan mass ratio) is greater than 1, preferably between 1 and 30, preferably between 1 and 25, and preferably between 5 and 20.

16. A method for cosmetic and / or care of the skin and / or skin appendages, wherein a composition according to any one of claims 1 to 15 is applied to the skin and / or skin appendages.

Images