Cosmetic composition comprising an elastic chitosan-based mixture

Abstract

Cosmetic composition comprising an elastic chitosan-based mixture. The invention relates to a composition comprising a mixture capable of forming a flexible elastic film comprising chitosan, or one of its salts or derivatives, a modified polysaccharide, and a polyol, which provides a tightening effect and deforms elastically to follow the movements and mechanical deformations of the skin surface. The present invention also relates to a method for preparing a cosmetic composition according to the invention, as well as a skincare method comprising a step of applying a cosmetic composition according to the invention to the skin.

Description

Title of the invention: Cosmetic composition comprising an elastic chitosan-based mixture technical field

[0001] The present invention relates to the cosmetic field, and more particularly to a cosmetic composition comprising a mixture capable of forming an elastic film, which provides a tightening effect and deforms elastically to follow the movements and mechanical deformations of the skin surface. The present invention also relates to a method for preparing a cosmetic composition according to the invention, as well as a skincare method comprising a step of applying a cosmetic composition according to the invention to the skin.

[0002] Giving cosmetic compositions a smoothing effect is a well-established technique in cosmetology. This can be achieved using active ingredients that penetrate the skin and have a long-lasting effect. Film-forming polymers are also used for a smoothing effect, providing immediate mechanical action on the skin's surface. However, these smoothing materials have some drawbacks. First, once the product is applied to the skin, it is often uncomfortable due to the rigidity of the films formed. This rigidity makes the films difficult to stretch and inelastic, consequently leading to poor durability of the cosmetic compositions, which crack and crumble quickly.

[0003] The Applicant has already described in application WO 2013 / 167835 a cosmetic treatment providing a tightening and smoothing effect comprising a specific elastic complex made up of at least one gelling or thickening starch, at least one polyol, and at least one polymer selected from polyvinyl alcohols, vinylpyrrolidone polymers and copolymers, and latex. However, these compositions have the disadvantage of being too sticky; they also lack adhesion to the skin (peelability problem).

[0004] The inventors have now developed a cosmetic composition comprising a mixture of specific compounds capable of forming an elastic film with an immediate, visible, and lasting smoothing effect. The film thus formed can deform reversibly, so that after deformation, for example after stretching, it returns to the state it had before the application of the mechanical stress provided, for example by deformation of the skin. The film formed by the cosmetic composition comprising said mixture has greater resistance to breakage, which makes it possible to maintain the mechanical properties of the film formed on the skin surface intact. Once incorporated into a cosmetic composition, the mixture capable of forming this elastic film has an effect This combined tensor and enhanced elastic formula is capable of following the skin's movements without cracking. The resulting effect is comparable to a shaping effect, as the cosmetic composition of the invention provides elasticity to skin naturally subjected to deformations, such as changes in facial expression or contact with hands or clothing. The inventors have thus succeeded in developing a cosmetic composition capable of combining performance characteristics that are difficult to reconcile: a tensor effect combined with an elastic effect, resolving the tensor / elasticity paradox. The new cosmetic composition is capable of effectively smoothing the skin's surface, notably achieving partial or total erasure of wrinkles, including medium and deep wrinkles.

[0005] The cosmetic composition of the invention exhibits remarkable skin-tightening and elastic properties, which are linked to the simultaneous presence of a chitosan, salt or derivative, a modified polysaccharide, and a polyol. The resulting cosmetic composition provides a visible and lasting smoothing of the skin's surface with exceptional user comfort.

[0006] General description of the invention

[0007] The present invention relates first to a cosmetic composition comprising a mixture capable of forming an elastic film comprising: a- at least one polysaccharide selected from chitosan, its salts and derivatives, and mixtures thereof, b- at least one modified polysaccharide different from polysaccharide a-, and mixtures thereof, and c- at least one polyol.

[0008] In the following description, the term "cosmetic composition" refers both to the cosmetic composition according to the invention and to the cosmetic composition used in the process of the invention. In the description, the terms "elastic mixture" and "mixture capable of forming an elastic film" are used interchangeably.

[0009] A polymer is said to be film-forming within the meaning of the invention if, after evaporation of the volatile substances present in the medium, a film is observed to form. Intermolecular bonds, responsible for the mechanical properties, then form between the polymer chains and with other components such as plasticizers to create a film that does not penetrate the skin and provides resistance to water and sebum, non-transfer, etc.

[0010] The elastic blend of the cosmetic composition of the invention comprises an α-polysaccharide, also called a contractile film-forming polymer, which provides an immediate smoothing / tightening (lifting) effect. This contractile effect occurs upon drying, as hydrogen bonds form between the polymer chains to create contraction.

[0011] The α- polysaccharide of the invention is advantageously an unmodified chitosan or a modified chitosan. The chitosans that may be used in the context of the invention may be fully or partially deacetylated chitins. The molecular mass of the chitosan used may vary from 20,000 to approximately 5,000,000 g / mol, preferably from 100,000 to 700,000 g / mol*. The degree of deacetylation of the chitosan may preferably vary from 50 to 99%.

[0012] In a preferred embodiment, the polysaccharide a- is an unmodified chitosan or a modified chitosan selected from alkylated chitosanes, hydroxyalkylated chitosanes, carboxylated chitosanes, acylated chitosanes, quaternized chitosanes, and mixtures thereof.

[0013] According to one embodiment, the cosmetic composition of the invention comprises from 0.1 to 15%, preferably from 0.5 to 10%, and more preferably from 1 to 5%, by weight of a- polysaccharide relative to the total weight of said cosmetic composition.

[0014] Unmodified chitosan is advantageously selected from fungal (CHITOSAN FUNGAL) or crustacean chitosan, for example from crabs, lobsters, squid, or shrimp. In a particularly preferred embodiment, the α- polysaccharide is fungal chitosan (CHITOSAN FUNGAL).

[0015] The elastic mixture of the cosmetic composition of the invention also comprises a modified β-polysaccharide, also called an elastic film-forming polymer, which provides an elastic (comfortable) effect to the composition. The modified β-polysaccharide of the invention has the advantage of providing, when mixed with the other ingredients, a dry, elastic film that is transparent and remains transparent after undergoing mechanical deformation (stretching). In particular, the film formed on the skin retains its transparency under the effect of multiple mechanical stresses, so that it does not, over time, alter the color of the cosmetic composition deposited on the skin into which the mixture has been incorporated.

[0016] The modified β- polysaccharide, different from the α- polysaccharide, is advantageously a modified starch. The modified starches of the invention are obtained from native starches that have been modified chemically and / or physically and / or enzymatically to improve their elastic properties. The native starches can come from a wide variety of sources, such as, for example, starches from maize, wheat, rice, buckwheat, barley, oats, millet, rye, sorghum, cassava, potato, sweet potato, tapioca, banana, plantain, malanga, taro, chestnut, beans, peas, and preferably native starches from maize, wheat, rice, cassava, potato, tapioca, and peas.

[0017] The modified starches used in the context of the invention have the advantage of providing, when mixed with the other components of the invention, elastic dry films that are transparent and remain transparent after stretching when prepared in the form of thin films (typically of thicknesses less than millimeter). Indeed, it is particularly advantageous in the context of the present invention that the film formed on the skin by application of the cosmetic composition of the invention retains its transparency under the effect of multiple mechanical stresses, and does not disturb over time the color of the deposit on the skin.

[0018] Among the preferred modified starches, alkylated starches, hydroxyalkylated starches, acetylated starches, starch hydrolysates, oxidized starches, phosphated starches, hydroxyalkylated, phosphated or acetylated distarch phosphates, and mixtures thereof, and preferably hydroxyalkylated starches.

[0019] The modified β- polysaccharide is advantageously selected from among hydroxyalkylated starches. In a preferred embodiment, the modified β- polysaccharide is hydroxypropyl starch, which may have the INCI name: HY-DROXYPROPYL STARCH, marketed for example by the company ROQUETTE.

[0020] In a particularly preferred embodiment, the modified β-polysaccharide is a hydroxyalkylated starch, and even more preferably a hydroxypropyl starch, having a weight-average molecular weight greater than 106 Da, and advantageously from 106 to 109 Da. The weight-average molecular weight can be determined by HPSEC-MALLS (high-performance size exclusion chromatography coupled online with multi-angle laser light scattering detection).

[0021] The modified b- polysaccharide preferably represents 1 to 15%, preferably 2 to 10%, and more preferably 4 to 8%, by weight relative to the total weight of the cosmetic composition.

[0022] The elastic mixture of the cosmetic composition of the invention also comprises a c- polyol, which aids in the dispersion and plasticizes the polymers present in the cosmetic composition. Thus, the c- polyol acts as a plasticizer by providing mobility between the polymer chains, making them more elastic and flexible.

[0023] The c-polyol of the invention may be an alcohol having from 1 to 30 carbon atoms and 2 to 12 hydroxyl groups, and in particular an alcohol having from 2 to 10 carbon atoms and 2 to 4 hydroxyl groups. The c-polyol may also be a sugar such as glucose, sorbitol, or mannitol. Advantageously, the c-polyol has a weight-average molecular weight ranging from 300 to 800 Da.

[0024] The c- polyol is advantageously selected from among diols, polyglycerols of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 2 to 10, and preferably from 2 to 4, and their mixtures.

[0025] According to one embodiment, the c- polyol is a diol selected from aliphatic or aromatic, linear or branched C2-Ci2 diols, preferably propane-1,2-diol, propane-1,3-diol, butane-1,2-diol, butane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, octane-1,8-diol, and mixtures thereof, and more preferably preferentially propane-1,3-diol.

[0026] According to another embodiment, the c- polyol is a polyglycerol of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 2 to 10.

[0027] According to a particularly advantageous embodiment, the c- polyol is a polyglycerol of the formula H-(O-CH2-CH(OH)-CH2)n-OH in which n = 3 and / or 6 (POLYGLYCERIN-3 (PGL-S MB) and / or POLYGLYCERIN-6 (POLYGLYCERIN 500 MB)), marketed, for example, by SAKAMOTO YAKUHIN KOGYO. More specifically, it is the polyglycerol of the formula H-(O-CH2-CH(OH)-CH2)n-OH in which n = 3 (POLYGLYCERIN-3), marketed by SAKAMOTO YAKUHIN KOGYO under the reference PGL-S MB. Compared to other polyols, POLYGLYCERIN-3 allows for a better level of plasticization of the a- polysaccharide and the modified b- polysaccharide on the skin surface.

[0028] The c- polyol preferably represents 1 to 20%, preferably 3 to 15%, and more preferably 5 to 10%, by weight relative to the total weight of the cosmetic composition.

[0029] In one embodiment, the cosmetic composition of the invention comprises: a- from 0.1 to 15%, preferably from 0.5 to 10%, and more preferably from 1 to 5%, by weight of polysaccharide a-, b- from 1 to 15%, preferably from 2 to 10%, and more preferably from 4 to 8%, by weight of b- modified polysaccharide, and c- from 1 to 20%, preferably from 3 to 15%, and more preferably from 5 to 10%, by weight of c- polyol, relative to the total weight of the cosmetic composition.

[0030] The quantities of each of the constituents a-, b-, and c- are preferably chosen so that the cosmetic composition provides a pleasant feel without being too sticky, while ensuring good adhesion to the skin. Thus, the proportions of each of the constituents a-, b-, and c- are adjusted to satisfy the desired compromise between stickiness and adhesion properties. Depending on the formula, for example, if it is a foundation or a serum, a compromise will be sought between adherence to the skin and the viscoelasticity of the composition. For example, if the formula contains powders, the quantity of polyol to be introduced will be greater in order to maintain a certain degree of plasticity and elasticity.

[0031] The mass ratio between the c- polyol and the two a- and b- polysaccharides is preferably between 20 / 80 and 80 / 20, and preferably between 40 / 60 and 60 / 40.

[0032] According to a particularly advantageous embodiment, the cosmetic composition of the invention comprises a mixture capable of forming an elastic film comprising: a- at least one polysaccharide selected from fungal chitosan (CHITOSAN) FUNGAL), b- at least one modified polysaccharide selected from hydroxypropyl starch (HYDROXYPROPYL STARCH), and c- at least one polyol selected from polyglycerol of formula H-(O-CH2 -CH(OH)-CH2)n-OH in which n = 3 and / or 6 (POLYGLYCERIN-3 and / or POLY-GLYCERIN-6), advantageously in the preferred weight % indicated above.

[0033] In the mixture suitable for forming an elastic film of the cosmetic composition of the invention, the polysaccharide a-, the modified polysaccharide b-, and the polyol c-, are preferably present in proportions such that the elasticity of the dry (water-free) film, with a thickness between 50 and 1000 microns, obtained from said mixture is characterized by:

[0034] - a loss of elasticity, measured after at least one tensile test, of less than 20%, and

[0035] - a resilience of at least 50%.

[0036] The elasticity of the elastic mixture present in the cosmetic composition of the invention can be measured by a method well known to those skilled in the art, for example with a TA.XT Plus reference texture analyzer (Stable Micro Systems), by measuring the force exerted by a dry film obtained from the mixture and subjected to a tensile test at a controlled speed. The thickness of the film chosen for this measurement is preferably between 50 and 1000 microns, and more preferably between 200 and 400 microns.

[0037] The tensile test consists of applying two opposing forces to the sample. The ends of a film sample are clamped between two jaws of the tensile testing machine, one fixed and the other attached to a pneumatic piston. The sample is then subjected to uniaxial stretching at a controlled rate over a given distance. The forces are recorded by the force sensor located on the fixed part of the machine, and a graph is plotted showing the force exerted by the sample as a function of the sample's elongation, as well as a graph showing the force exerted by the sample as a function of time.

[0038] The residual strain rate is preferably measured after at least one tensile step, at a specified distance equal to one-third of the sample length, for example, at a distance ranging from one-third to four times its length. Alternatively, successive stretching cycles can be performed by gradually increasing the stretching distance.

[0039] The amount of elastic mixture introduced into the cosmetic composition of the invention is advantageously chosen according to the desired cosmetic effect and viscosity. Indeed, the viscosity of the product must be compatible with regular, pleasant, and sufficient application to the skin. The amount of mixture suitable for forming an elastic film is chosen in particular to allow the formation of an elastic film at the time of application of the cosmetic composition to the skin.

[0040] The proportions of the different components will be optimized to achieve the correct viscoelasticity and adherence to the skin. Depending on the formula, for example, whether it is a foundation or a serum, a compromise will be sought between adherence to the skin and the viscoelasticity of the cosmetic composition. For example, if the formula contains powders, the amount of polyol to be introduced will be greater in order to maintain the plasticity and elasticity of the cosmetic composition.

[0041] In an advantageous embodiment, the cosmetic composition of the invention contains from 0.5 to 50%, preferably from 1 to 30%, and more preferably from 5 to 25%, by weight relative to the total weight of the cosmetic composition, of a mixture capable of forming an elastic film consisting of polysaccharide a-, modified polysaccharide b-, and polyol c-, as defined above.

[0042] The cosmetic composition of the invention may further comprise an aqueous phase, which may include water. Preferably, the composition comprises from 40 to 99%, preferably from 50 to 90%, and more preferably from 60 to 70%, by weight of water, relative to the total weight of the cosmetic composition.

[0043] According to one embodiment of the invention, the cosmetic composition may further comprise at least one cosmetic active ingredient. The cosmetic active ingredient may, in particular, advantageously be chosen from among a moisturizing agent, an anti-wrinkle agent, an antioxidant, a free radical scavenger, an agent that repairs the destructive effects of ultraviolet rays, or a slimming agent such as caffeine. Preferably, the cosmetic active ingredient is chosen from among hyaluronic acids, such as sodium hyaluronate. The invention thus relates, according to one of its aspects, to a cosmetic composition containing water and at least one cosmetic active ingredient in a proportion ranging from 0.01 to 5% by weight, relative to the total weight of the cosmetic composition.

[0044] The cosmetic composition of the invention may further include a gelling agent. Suitable gelling agents include natural or synthetic polysaccharides, preferably chosen from xanthan gum (such as Rhodicare® XC or T sold by Solvay Novecare or Keltrol CG LAXT sold by CP Keltro), agar-agar (such as Ina Agar CS 83 sold by Iwase Cosfa), gellan gum (such as Kelcogel® CG-LA sold by Azelis), carrageenans (such as Satiagum™ VPC 430 sold by Cargill Beauty), cellulose and its derivatives such as hydroxyethylcellulose (such as Klucel® GF sold by Ashland) and hydroxypropylcellulose, corn starch, cellulose carboxymethyl ethers (such as Blanose™ 7H3SF sold by Ashland), and bis-decyltetradeceth-20 ether-based copolymers (such as Adeka Nol GT-700 sold by Adeka), polysaccharide alcaligens (such as Alcasealan sold by Iwase Cosfa), and their mixtures. We Synthetic polymers may also be advantageously cited, preferably selected from ammonium acryloyldimethyltaurate / VP copolymer (Aristoflex® AVC from Clariant International Ltd.) or acrylates / C 10-30 alkyl acrylate crosspolymer (Carbopol® Ultrez 21). Particularly advantageously, the gelling agent is selected from xanthan gum (such as Rhodicare® XC or T sold by Solvay Novecare or Keltrol CG LAXT sold by CP Keltro), alkaligene polysaccharides (such as Alcasealan sold by Iwase Cosfa), acrylates / C10-30 alkyl acrylate crosspolymer (Carbopol® Ultrez 21), ammonium acryloyldimethyltaurate / VP copolymer (Aristoflex® AVC from Clariant International Ltd.), and mixtures thereof.

[0045] The cosmetic composition of the invention may further comprise at least one pH adjusting agent. This pH adjusting agent is advantageously chosen from alkali hydroxides such as sodium hydroxide or ammonium hydroxide, triethanolamine, 2-amino-2-(hydroxymethyl)-1,3-propanediol, borates, phosphates, pyrophosphates, ascorbic acid and its salts such as trisodium citrate dihydrate, sorbic acid and its salts, phosphoric acid and its salts, citric acid and its salts, lactic acid and its salts, boric acid and its salts, acetic acid and its salts, preferably alkali hydroxides, and more preferably an alkali hydroxide such as sodium hydroxide. The pH adjusting agent is advantageously used in an amount capable of giving the cosmetic composition a pH ranging from 4 to 7.According to one embodiment, the pH adjusting agent is present in an amount ranging from 0.01 to 1% by weight relative to the total weight of the cosmetic composition.

[0046] The cosmetic composition of the invention may further include one or more cosmetic excipients such as opacifying agents, perfumes, reflective agents, coalescing agents, preservatives such as chlorphenesin (INCI name: CHLORPHENESIN), UVA and UVB ultraviolet protection agents, in particular filters, organic pigments and nanopigments, such as zinc, iron and titanium oxides.

[0047] The cosmetic composition of the invention may be in the form of a gel, a lotion, a serum, a suspension, an oil-in-water emulsion, a water-in-oil emulsion, or a mask, and preferably in the form of a serum or an oil-in-water emulsion.

[0048] Another object of the invention relates to a method for preparing a cosmetic composition according to the invention, as described above.

[0049] The process for preparing the cosmetic composition of the invention comprises the following steps: (i) preparation of a mixture capable of forming an elastic film by dissolving at least one a- polysaccharide, at least one b- modified polysaccharide, and at least a c- polyol, in water, and (ii) dispersion of the mixture obtained in step (i) in an aqueous phase possibly including cosmetic active ingredients and / or excipients.

[0050] Advantageously, step (i) is carried out, under stirring, at a temperature ranging from 50 to 120°C, and preferably from 70 to 100°C, for a period ranging from 5 minutes to 1 hour, and preferably for about 30 minutes. The mixture obtained at the end of step (i) is then cooled to room temperature (20°C).

[0051] In step (i), the elastic mixture can be prepared by first dissolving the polyol c- in water. The polysaccharide a- is then dissolved or dispersed in the water-polyol c- mixture, possibly with the addition of heat and stirring. Once the polysaccharide a- has dissolved or dispersed, the modified polysaccharide b- is then added, with the addition of heat to thoroughly homogenize the different components. Advantageously, the polysaccharide a- and the modified polysaccharide b- are added successively, with stirring, at a temperature ranging from 50 to 120°C, and preferably from 70 to 100°C, for a period ranging from 5 minutes to 1 hour, and preferably for about 30 minutes. The mixture obtained at the end of step (i) is then cooled to room temperature (20°C).

[0052] In step (ii), the mixture prepared in step (i) is added to an aqueous phase comprising cosmetic actives and / or other cosmetic excipients.

[0053] According to another embodiment, the cosmetic composition of the invention is prepared by successively adding each of the components polysaccharide a-, modified polysaccharide b-, and polyol c-, directly into the aqueous phase of the cosmetic composition, without prior mixing. Advantageously, the components polysaccharide a-, modified polysaccharide b-, and polyol c- are added successively, with stirring, at a temperature ranging from 50 to 120°C, and preferably from 70 to 100°C, for a period ranging from 5 minutes to 1 hour, and preferably for approximately 30 minutes. The mixture obtained at the end of step (i) is then cooled to room temperature (20°C).

[0054] In the particular case of an emulsion, the components polysaccharide a-, modified polysaccharide b-, and polyol c-, are added to the aqueous dispersing phase before dispersion of the oily phase.

[0055] Finally, a last object of the invention relates to a skin care process comprising a step of applying a cosmetic composition as defined according to the invention, on at least one part of the body and / or face.

[0056] In one embodiment, the application step on at least one part of the body and / or face is carried out on at least one area of ​​skin, in particular the face and / or décolleté, showing signs of aging or fatigue such as loss of firmness, loss of elasticity, or sagging skin, to obtain an effect chosen from a smoothing effect, a tightening effect, a skin-bouncing effect, or a combination of these effects.

[0057] The cosmetic composition, when applied directly to the skin, forms a film after application and gradual evaporation of the water in the composition. This film exhibits elastic mechanical properties and a texture particularly well-suited to makeup application. Furthermore, this type of texture possesses properties that are useful both aesthetically and in terms of user comfort, especially near highly mobile areas such as the eyes and lips. The elastic properties of the cosmetic composition of the invention are particularly useful for application to areas of the body subject to significant movement, such as the skin of the face.

[0058] The skin care process may include the topical application to the affected areas of skin of an effective amount of a cosmetic composition according to the invention as defined above, to obtain a second-skin sensation.

[0059] In addition to the foregoing provisions, the invention also includes other provisions which will become apparent from the following supplementary description, which relates to the preparation of cosmetic compositions according to the invention.

[0060] Examples:

[0061] In the examples, and unless otherwise indicated, all percentages are given as mass percentages, ingredients are designated by their INCI name, and the temperature is given in degrees Celsius.

[0062] Methods for characterizing elastic films: - Elastic properties (resistance to fatigue): Fatigue resistance was evaluated using a TA.XT Plus texture analyzer (Stable Micro Systems). Prepared elastic films were poured into Teflon® molds and then dried at 33°C under 50% relative humidity to a thickness of 200 to 400 µm sec. 5 x 3 cm specimens were then cut and subjected to repeated stretching: 25 stretch cycles at 50% back and forth at 1 mm / second. Elastic properties (fatigue resistance) were classified from most elastic (+++) to least elastic (+). - Evaluation of the contractile effect on nitrile support: The contractile effect of the elastic films was visually evaluated at room temperature (20°C). A nitrile glove cut into a 3 x 5 cm test specimen was used as a support. The elastic mixtures were spread with a spatula onto the nitrile support to obtain a dry film mass of 0.05 g, corresponding to a dry film thickness (or remaining dry mass) of 33 µm, and then left to dry for 24 hours at room temperature (20°C). During the drying of the elastic films, these The latter retract to varying degrees and are classified into three categories:

[0063] Category 1: the support is not retracted, the film exhibits no contractile effect,

[0064] Category 2: the support has slightly retracted compared to the start of the test, an effect contractile muscle is visible.

[0065] Category 3: the support has retracted and rolled up on itself, the contractile effect is significant. - Method for characterizing the smoothing effect in vivo at 1 hour and 4 hours: The aim of the test is to evaluate and compare the smoothing effect on the area at the corner of the eye known as "crow's feet" after 1 hour and 4 hours on a panel of 10 volunteers. All measurements were taken at a temperature of 22°C and 50% relative humidity.

[0066] 1- Taking an impression

[0067] A first impression was taken before application of the evaluated cosmetic composition. To create the impression, a film-forming resin was spread using a spatula over the area being studied. After drying, the replica of the skin area was peeled off.

[0068] The product was applied to the crow's foot in an amount of 2 mg.cm2, left to dry for 15 minutes, then measurements were taken after 1 hour and 4 hours.

[0069] A second impression was taken 1 hour and then 4 hours after application of the cosmetic composition. The same protocol was repeated for each cosmetic composition studied.

[0070] 2- Image analysis

[0071] Each replica was positioned on a support and illuminated with a grazing light at an angle of incidence of 35° to generate shadows behind each line of the skin surface. These shadows were then analyzed on high-resolution images of the replica to obtain numerical values ​​of the gray levels of each analyzed pixel.

[0072] Device used:

[0073] The QU ANTIRIDES® software calculates the following parameters: number of wrinkles, total surface area of ​​wrinkles in mm2, total length of wrinkles in mm, average length of wrinkles in mm, average depth of wrinkles in pm.

[0074] The smoothing effect was evaluated by comparing these parameters before and after application of the cosmetic composition (1 hour and 4 hours after application). The greater the reduction in the areas of wrinkles, their length and / or their surface area or depth, the more significant the observed smoothing effect.

[0075] Evaluation criteria:

[0076] +++ means that the product has a very significant smoothing effect on crow's feet, 1 or 4 hours after application,

[0077] ++ means that the product has a significant smoothing effect on crow's feet, 1 or 4 hours after application, and

[0078] + means that the product has little smoothing effect on crow's feet, 1 or 4 hours after application.

[0079] Example 1: Preparation and characterization of mixtures

[0080] Two elastic mixtures A and B according to the invention and a mixture C outside the invention corresponding to the formulas in Table 1, were prepared:

[0081] [Tables 1] Polysaccharide a-(% by weight) Modified polysaccharide b-(% by weight) Polyol c-(% by weight) Elastic mixture A CHITOSAN FUNGAL: 3% HYDROXYPROPYL STARCH: 8% PROPANE-1,3-DIOL: 6% Elastic mixture B CHITOSAN FUNGAL: 2% HYDROXYPROPYL STARCH: 10% PROPANE-1,3-DIOL: 5% Elastic mixture C CHITOSAN FUNGAL: 0% HYDROXYPROPYL STARCH: 10% VEGETABLE GLYCEROL: 5%

[0082] Three aqueous dispersions, each comprising one of the mixtures A, B and C, were prepared according to the formula in Table 2 below:

[0083] [Tables2] Ingredients (chemical names or INCI) Quantities (% by weight) PURIFIED WATER q.s. SODIUM HYDROXIDE 0.05 POLYOL C- 9.00 POLYSACCHARIDE A- 3.00 MODIFIED POLYSACCHARIDE B- 8.00

[0084] Purified water, sodium hydroxide, and the c- polyol were weighed into a beaker and then mixed using a deflocculating turbine at 150 rpm in a water bath at 80°C. The a- polysaccharide was weighed into a capsule and then sprinkled into the beaker while stirring at 400 rpm. Once the mixture was homogeneous, the b- polysaccharide was weighed into a capsule and then sprinkled into the beaker while stirring at 600 rpm. Once the mixture was homogeneous, the prepared mixture was removed from the water bath and cooled to room temperature while stirring at 300-400 rpm. The prepared mixtures were then used to form elastic films, which have been evaluated.

[0085] The measured characteristics for elastic mixtures A, B and C are summarized in the following Table 3:

[0086] [Tables3] Elastic properties Category of contractile effect Elastic mixture A++ 3 Elastic mixture B+++ 2 Elastic mixture C++ 1

[0087] Elastic mixtures A and B comprising the three components a-, b- and c- are those which allow the best compromise between tensor effect and elastic effect.

[0088] Example 2: Serum according to the invention

[0089] A serum composition according to the invention corresponding to the formula in Table 4 was prepared according to the following protocol:

[0090] [Tables4] Ingrédients (noms chimiques ou INCI) Phases Quantités (% en poids) GLYCERIN Al 3,50 POLYGLYCERIN-3 Al 6,75 SODIUM SURFACTIN A2 0,05 HYDROGENATED LECITHIN A 0,50 SQUALANE VEGETAL B 3,50 LIMNANTHES ALBA SEED OIL B 2,50 EAU PURIFIEE Cl 66,32 CHLORPHENESIN Cl 0,27 SODIUM HYDROXIDE Cl 0,03 CHITOSAN FUNGAL C2 2,25 HYDROXYPROPYL STARCH C3 6,00 DIGLYCERIN D 2,00 LAUROYL LYSINE D 1,00 ALCOHOL A 96,2% VOL KG E 5,00 TRISODIUM ETHYLENEDIAMINE DL SUCCINATE F 0,03 CAPRYLYL GLYCOL F 0,30

[0091] The ingredients of phase A1 were weighed into a beaker and then mixed under slow stirring with a deflocculating turbine in a water bath at 80°C. Phase A2 was weighed and added to phase A1. Phase B was weighed, emulsified in phase A, and then mixed at 600 rpm. Phase C1 was weighed and then slowly stirred with a deflocculating turbine in a water bath at 80°C. Phase C2 was weighed into a capsule and then added as a fine spray to C1. Phase C3 was weighed into a capsule and then added as a fine spray to phases C1 and C2. All of phase C was emulsified with phase A in a water bath at 80°C. The temperature was then cooled to room temperature. Phase D was weighed into a capsule and then added to the beaker. Phases E and F were weighed in capsules, then added to the beaker.

[0092] The mixture thus prepared allowed the formation of an elastic film, exhibiting the following properties: Smoothing effect evaluation at 1 hour. Smoothing effect evaluation at 4 hours. Serum from example 2 ++ +++

[0094] Example 3: Eye contour cream according to the invention

[0095] An eye contour cream composition according to the invention meeting the The formula in Table 6 was prepared according to the following protocol:

[0096] [Tableauxô] Ingrédients (noms chimiques ou INCI) Phases Quantités (% en poids) STEARETH-2 A 0,50 COCO-CAPRYLATE / CAPRATE A 2,00 SOYBEAN GLYCERIDES (AND) BUTY-ROSPERNUM PARKII (SHEA) BUTTER UNSAPONIFIABLES A 2,00 DIMETHICONE A 0,20 ETHYLHEXYL STEARATE A 2,90 CETYL ALCOHOL A 1,40 PROPYLENE GLYCOL DICAPRYLATE / DICAPRATE A 2,50 STEARYL ALCOHOL A 1,40 CANDELILLA CERA A 0,50 STEARETH-21 A 1,00 MANGIFERA INDICA SEED BUTTER A 0,50 EAU PURIFIEE B1 65,00 CHLORPHENESIN B1 0,27 SODIUM HYDROXIDE B1 0,03 POLYGLYCERIN-3 B1 6,75 CHITOSAN FUNGAL B2 2,25 HYDROXYPROPYL STARCH B3 6,00 GLYCERIN C 3,50 CELLULOSE C 1,00 CAPRYLYL GLYCOL D 0,30

[0097] The ingredients of phase A were weighed into a beaker and then mixed under stirring with a deflocculating turbine in a water bath at 85°C. Phase B1 was weighed into a beaker and then mixed under stirring with a deflocculating turbine in a water bath at 85°C. Phase B2 was weighed into a capsule and added to phase B1 as a fine spray, then mixed under stirring at 300 rpm for 20 minutes. Phase B3 was weighed and then added to phases B1 and B2 as a fine spray, and mixed under stirring at 600 rpm for 30 minutes. The entire phase B mixture was debubbled by reducing the stirring speed to 200 rpm. Phase B was emulsified in phase A by slowly pouring phase B into phase A in a water bath at 85°C and gradually increasing the stirring speed to 800 rpm. The mixture was stirred at this speed for 10 minutes, then removed from the water bath.Phase C was weighed in a capsule and then added to the beaker at a temperature of 50°C. Phase D was weighed and then added to the beaker at a temperature below 40°C.

[0098] The mixture thus prepared allowed the formation of an elastic film, exhibiting the following properties:

[0099] [Tables?] Smoothing effect evaluation at 1 hour. Smoothing effect evaluation at 4 hours. Example cream 3 ++ +++

[0100] Example 4: Serum according to the invention and comparative serum

[0101] A serum composition according to the invention conforming to the formula in Table 8 was prepared according to the following protocol: Ingrédients (noms chimiques ou INCI) Phases Quantités (% en poids) GLYCERIN A 3,50 PROPANE- 1,3-DIOL A 4,50 SODIUM SURFACTIN A 0,05 HYDROGENATED LECITHIN A 0,50 SQUALANE VEGETAL B 3,50 LIMNANTHES ALBA SEED OIL B 2,50 EAU PURIFIEE Cl 71,32 CHLORPHENESIN Cl 0,27 SODIUM HYDROXIDE Cl 0,03 CHITOSAN FUNGAL C2 1,50 HYDROXYPROPYL STARCH C3 4,00 GLYCERIN D 1,50 PENTYLENE GLYCOL VEGETAL D 0,50 LAUROYL LYSINE D 1,00 ALCOHOL E 5,00 TRISODIUM ETHYLENEDIAMINE DL SUCCINATE F 0,03 CAPRYLYL GLYCOL F 0,30

[0103] The ingredients of phase A were weighed into a beaker and then mixed under slow stirring with a deflocculating turbine in a water bath at 80°C. Phase B was weighed into a capsule and then emulsified into phase A by increasing the stirring speed to 600 rpm. Phase C1 was weighed into a beaker and then mixed under slow stirring with a deflocculating turbine in a water bath at 80°C. Phase C2 was weighed into a capsule and added to phase C1 as a fine spray. Phase C3 was weighed into a capsule and then added to phases C1 and C2 as a fine spray. The entire C phase was emulsified into phase A at 80°C and then cooled to room temperature. Phase D was weighed into a capsule and then added to the beaker. Phases E and F were weighed in capsules, then added to the beaker.

[0104] The mixture thus prepared allowed the formation of an elastic film, exhibiting the following properties: Smoothing effect evaluation at 1 hour. Smoothing effect evaluation at 4 hours. Serum from example 4 ++ +++

[0106] A serum formulation similar to that of Example 4, but free of the modified β-polysaccharide (HYDROXYPROPYL STARCH), was prepared using the same procedure as before. The film formed proved uncomfortable because it was too tight, and then cracked due to a lack of elasticity.

[0107] The mixture thus prepared allowed the formation of a film, exhibiting the following properties:

[0108] [TableauxlO] Smoothing effect evaluation at 1 hour. Smoothing effect evaluation at 4 hours. Comparative serum of example 4 ++ No smoothing effect

[0109] Example 5: Eye contour cream according to the invention and comparative cream

[0110] An eye contour cream composition according to the invention corresponding to the formula in Table 11 was prepared according to the following protocol: Ingrédients (noms chimiques ou INCI) Phases Quantités (% en poids) STEARETH-2 A 0,50 COCO-CAPRYLATE / CAPRATE A 2,00 SOYBEAN GLYCERIDES (AND) BUTY-ROSPERNUM PARKII (SHEA) BUTTER UNSAPONIFIABLES A 2,00 DIMETHICONE A 0,20 ETHYLHEXYL STEARATE A 2,90 CETYL ALCOHOL A 1,40 PROPYLENE GLYCOL DICAPRYLATE / DICAPRATE A 2,50 STEARYL ALCOHOL A 1,40 CANDELILLA CERA A 0,50 STEARETH-21 A 1,00 BIS-BEHENYL / ISOSTEARYL / PHYTOSTE RYL DIMER DILINOLEYL DIMER DL LINOLEATE A 2,00 MANGIFERA INDICA SEED BUTTER A 0,50 EAU PURIFIEE B1 63,40 CHLORPHENESIN B1 0,27 SODIUM HYDROXIDE B1 0,03 GLYCEROL VEGETAL B1 4,00 PROPANE- 1,3-DIOL B1 4,50 SODIUM SURFACTIN B2 0,10 CHITOSAN FUNGAL B3 1,50 HYDROXYPROPYL STARCH B4 4,00 CELLULOSE C 2,00 PENTYLENE GLYCOL C 2,00 HYDROXYETHYL ACRYLATE / SODIUM ACRYLOYLDIMETHYL TAURATE COPOLYMER & ISOHEXADECANE & D 0,90 POLYSORBATE 60 CAPRYLYL GLYCOL E 0,40

[0112] The ingredients of phase A were weighed into a beaker and then mixed under stirring with a deflocculating turbine in a water bath at 85°C. Phase B1 was weighed into a beaker and then mixed under stirring with a deflocculating turbine in a water bath at 85°C. Phase B2 was weighed into a capsule and added to phase B1 as a fine spray, then mixed under stirring at 300 rpm for 20 minutes. Once phase B was homogenized, phase B3 was weighed and then added to phases B1 and B2. The entire phase B mixture was defoamed by reducing the stirring speed to 200 rpm. Phase B was emulsified in phase A by slowly pouring phase B into phase A in a water bath at 85°C, gradually increasing the stirring speed to 800 rpm. The mixture was stirred at this speed for 10 minutes and then removed from the water bath. Phase C was weighed into a capsule and then added to the beaker at a temperature of 50°C.Phases D and E were weighed and then added to the beaker at a temperature below 40°C.

[0113] The mixture thus prepared allowed the formation of an elastic film, exhibiting the following properties:

[0114] [Tables 12] Smoothing effect evaluation at 1 hour. Smoothing effect evaluation at 4 hours. Example cream: 5 ++ +++

[0115] A cream formula similar to that of Example 5, but free of the modified β-polysaccharide (HYDROXYPROPYL STARCH), was prepared using the same procedure as before. The film formed proved uncomfortable because it was too tight, and then cracked due to a lack of elasticity.

[0116] The mixture thus prepared allowed the formation of a film, exhibiting the following properties:

[0117] [Tables 13] Smoothing effect evaluation at 1 hour. Smoothing effect evaluation at 4 hours. Comparative serum of example 5 ++ No smoothing effect

[0118] Example 6: Creams according to the invention

[0119] Two cream compositions according to the invention corresponding to the formulas in Table 14 were prepared according to the following protocol: Ingredients (chemical names or INCI) Phases Quantities (% by weight) Formula 6a Formula 6b STEARETH-2 A 0.50 0.50 CETIOL C 5C A 2.00 2.00 LIPEXL'SENS A 2.00 2.00 DIMETHICONE A 0.20 0.20 ETHYLHEXYL STEARATE A 2.90 2.90 CETYL ALCOHOL A 1.40 1.40 MIGLYOL 840 A 2.50 2.50 STEARYL ALCOHOL A 1.40 1.40 CANDELILLA CERA A 0.50 0.50 BRU S721-PA A 1.00 1.00 MANGO KERNEL BUTTER A 0.50 0.50 PURIFIED WATER B1 65.00 65.00 CHLORPHENESIN B1 0.27 0.27 SODIUM HYDROXIDE B1 0.03 0.03 POLYGLYCERIN-3 B1 6.75 - PROPANE-1,3-DIOL B1 - 6.75 CHITOSAN FUNGAL B2 2.25 2.25 HYDROXYPROPYL STARCH B3 6.00 6.00 GLYCERIN C 3.50 3.50 CELLULOSE C 1.00 1.00 CAPRYLYL GLYCOL D 0.30 0.30

[0121] The ingredients of phase A were weighed into a beaker and then mixed under stirring with a deflocculating turbine in a water bath at 85°C. Phase B1 was weighed into a beaker and then mixed under stirring with a deflocculating turbine in a water bath at 85°C. Phase B2 was weighed into a capsule and added to phase B1 as a fine spray, then mixed under stirring at 300 rpm for 30 minutes at 85°C. Phase B3 was weighed into a capsule and then added to phases B1 and B2 as a fine spray, and mixed under stirring at 300 rpm for 30 minutes. The entire contents of phase B were unpacked, with the stirring speed reduced to 200 rpm. Phase B was emulsified with phase A in a water bath at 85°C, mixed for 10 minutes, and then removed from the water bath. Phase C was weighed into a capsule, mixed with a spatula, then added to phase B1 in a fine spray, and finally mixed under stirring at 300 rpm for 30 minutes at 85°C. Phase D was weighed and then added to the beaker at a temperature below 40°C.

[0122] The mixtures thus prepared allowed the formation of elastic films, exhibiting the following properties:

[0123] [Tables 14] Smoothing effect evaluation at 1 hour Smoothing effect evaluation at 4 hours Cream from example 6a ++ +++ Cream from example 6b +++ ++

[0124] Example 7: Liquid foundation according to the invention

[0125] A fluid foundation composition according to the invention corresponding to the formula of Table 15 was prepared according to the following protocol: Ingredients (chemical names or INCI) Phases Quantities (% by weight) C9-12 ALKANE Al 15.05 C15-19 ALKANE Al 1.00 COCO-CAPRYLATE / CAPRATE Al 1.00 ETHYLHEXYL SALICYLATE Al 4.50 CAPRYLIC / CAPRIC TRIGLYCERIDE Al 12.00 SODIUM MYRISTOYL GLUTAMATE A2 12.95 C9-12 ALKANE A2 3.50 COCO-CAPRYLATE / CAPRATE A2 1.20 POLYHYDROXYSTEARIC ACID A2 0.10 TITANIUM DIOXIDE A3 4.00 PURIFIED WATER B1 33.37 POLYHYDROXYSTEARIC ACID B1 0.30 SODIUM HYDROXIDE B1 0.03 CHITOSAN FUNGAL B2 1.50 HYDROXYPROPYL STARCH B3 4.00 POLYGLYCERIN-3 B4 4.50 PENTYLENE GLYCOL B5 1.00

[0127] The ingredients of phase A1 were weighed into a beaker and then mixed under stirring with a deflocculating turbine at room temperature. Phase A2 was weighed into a capsule, dispersed in phase A1, and then mixed under stirring with a deflocculating turbine at 150 rpm. Phase B1 was weighed into a beaker and then mixed under stirring with a deflocculating turbine in a water bath at 80°C. Phase B2 was weighed into a capsule and added to phase B1 as a fine spray. Phase B3 was weighed into a capsule and added to phases B1 and B2 as a fine spray. The mixture was then cooled to room temperature. Phases B4 and B5 were then added. The entire phase B was emulsified in phase A, then mixed under agitation using a deflocculating turbine at 1000 rpm for 5 minutes, then at 800 rpm for 30 minutes.

[0128] After application, the foundation produces a smoothing effect on the user's skin, without any feeling of tightness during the day.

Claims

Demands

1. Cosmetic composition characterized in that it comprises a mixture capable of forming an elastic film comprising: a- at least one polysaccharide selected from chitosan, its salts and derivatives, and mixtures thereof, b- at least one modified polysaccharide different from polysaccharide a-, and mixtures thereof, and c- at least one polyol, said modified polysaccharide b- being a modified starch selected from alkylated starches, hydroxyalkylated starches, acetylated starches, oxidized starches, phosphated starches, hydroxyalkylated, phosphated or acetylated distarch phosphates, and mixtures thereof.

2. Composition according to claim 1, characterized in that the polysaccharide a- is an unmodified chitosan or a modified chitosan selected from alkylated chitosan, hydroxyalkylated chitosan, carboxylated chitosan, acylated chitosan, qua-ternized chitosan, and mixtures thereof.

3. Composition according to claim 1 or claim 2, characterized in that the polysaccharide a- is an unmodified chitosan selected from fungal chitosan (CHITOSAN FUNGAL), crustacean chitosan, and mixtures thereof, and preferably fungal chitosan (CHITOSAN FUNGAL).

4. Composition according to any one of claims 1 to 3, characterized in that the modified polysaccharide b- is a modified starch selected from hydroxyalkylated starches.

5. Composition according to claim 4, characterized in that the modified polysaccharide b- is hydroxypropyl starch (HYDROXYPROPYL STARCH).

6. Composition according to claim 5, characterized in that the hydroxypropyl starch (HYDROXYPROPYL STARCH) has a weight average molecular weight greater than 106 Da, and preferably from 106 to 109 Da.

7. Composition according to any one of claims 1 to 6, characterized in that the c- polyol is selected from diols, polyglycerols of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 2 to 10, and preferably from 2 to 4, and mixtures thereof.

8. Composition according to any one of claims 1 to 7, characterized in that The c- polyol is a diol selected from among the aliphatic or aromatic C2-Ci2 diols, linear or branched, preferably propane-1,2-diol, propane-1,3-diol, butane-1,2-diol, butane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, octane-1,8-diol, and mixtures thereof, and more preferably propane-1,3-diol.

9. Composition according to any one of claims 1 to 8, characterized in that the c- polyol is a polyglycerol of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 2 to 10, and preferably from 2 to 4, the c- polyol being preferably a polyglycerol of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n = 3 and / or 6 (POLYGLYCERIN-3 and / or POLYGLYCERIN-6).

10. Composition according to any one of claims 1 to 9, characterized in that it comprises a mixture capable of forming a film comprising: a- at least one polysaccharide selected from fungal chitosan (CHITOSAN FUNGAL), b- at least one modified polysaccharide selected from hydroxypropyl starch (HYDROXYPROPYL STARCH), and c- at least one polyol selected from polyglycerol of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n = 3 and / or 6 (POLYGLYCERIN-3 and / or POLYGLYCERIN-6).

11. Composition according to any one of claims 1 to 10, characterized in that it comprises from 0.1 to 15%, preferably from 0.5 to 10%, and more preferably from 1 to 5%, by weight of α-polysaccharide relative to the total weight of the cosmetic composition.

12. Composition according to any one of claims 1 to 11, characterized in that it comprises from 1 to 15%, preferably from 2 to 10%, and more preferably from 4 to 8%, by weight of b-modified polysaccharide relative to the total weight of the cosmetic composition.

13. Composition according to any one of claims 1 to 12, characterized in that it comprises from 1 to 20%, preferably from 3 to 15%, and more preferably from 5 to 10%, by weight of c- polyol relative to the total weight of the cosmetic composition.

14. Composition according to any one of claims 1 to 13, characterized in that the weight ratio of polyol c- / (polysaccharide a- + modified polysaccharide b-) varies from 20 / 80 to 80 / 20, and preferably from 40 / 60 to 60 / 40.

15. Composition according to any one of claims 1 to 14 characterized in that the mixture of polysaccharide a-, modified polysaccharide b- and polyol c- represents from 0.5 to 50%, preferably from 1 to 30%, and more pre- from 5 to 25% by weight relative to the total weight of the cosmetic composition.

16. Composition according to any one of claims 1 to 15 characterized in that it comprises water, preferably in an amount from 40 to 99%, preferably from 50 to 90%, and more preferably from 60 to 70%, by weight relative to the total weight of the cosmetic composition.

17. Composition according to any one of claims 1 to 16 characterized in that it comprises a pH adjusting agent, preferably an alkali hydroxide such as sodium hydroxide, and more preferably in an amount from 0.01 to 1% by weight relative to the total weight of the cosmetic composition.

18. Composition according to any one of claims 1 to 17 characterized in that it is in the form of a gel, lotion, serum, suspension, oil-in-water emulsion, or mask, and preferably in the form of a serum or an oil-in-water emulsion.

19. A method for preparing a cosmetic composition according to any one of claims 1 to 18, characterized in that it comprises the following steps: (i) preparation of a mixture capable of forming a film by dissolving at least one polysaccharide a-, at least one modified polysaccharide b-, and at least one polyol c-, in water, and (ii) dispersion of the mixture obtained in step (i) in an aqueous phase optionally comprising cosmetic actives and / or excipients.

20. A skin care method characterized in that it comprises a step of applying a composition as defined according to any one of claims 1 to 18, to at least one part of the body and / or face.

21. A method according to claim 20, characterized in that the application step on at least one part of the body and / or face is carried out on at least one area of ​​skin, in particular of the face and / or décolleté, showing signs of aging or fatigue such as loss of firmness, loss of elasticity, or sagging skin, to obtain an effect selected from a smoothing effect, a tightening effect, a skin-bouncing effect, or a combination of one of these effects.