EMULSIFYING COMPOSITION COMPRISING A WATER-IN-OIL EMULSIFIER AND A CYCLODEXTRIN OF SELECTED PARTICLE SIZE, CAPABLE OF PROVIDING AN OIL-IN-WATER EMULSION WITH IMPROVED SENSORY EFFECTS FOR COSMETIC USE

Abstract

The present invention relates to a sensory emulsifying composition, in particular for cosmetic use, capable of obtaining a liquid oil-in-water-type emulsion comprising at least one cyclodextrin in the form of solid particles, said particles having a volumetric average particle size d(4,3), measured by laser granulometry, of between 2 and 20 μm, preferably between 3 and 12 μm, and more preferably between 4 and 8 μm, and at least one emulsifier of natural origin selected from water-in-oil emulsifiers, having a hydrophilic-lipophilic balance (HLB) of less than 8.

Claims

1. An emulsifying composition, preferably for cosmetic use, capable of obtaining a liquid oil-in-water-type emulsion comprising: a) at least one cyclodextrin in the form of solid particles, said particles having a volumetric average particle size d(4.3), measured by laser granulometry, of between 2 and 20 μm, preferably between 3 and 12 μm, and more preferably between 4 and 8 μm, b) and at least one emulsifier of natural origin selected from water-in-oil-type emulsifiers, having a hydrophilic-lipophilic balance of less than 8, most preferably of less than or equal to 7.

2. The emulsifying composition according to claim 1, wherein the cyclodextrin particles have a volumetric particle size distribution, measured by laser diffraction granulometry, the characteristic diameters d(10), d(50) and d(90) of which are such that: a) The diameter d(10) is of less than or equal to 5.0 μm, preferably of less than or equal to 2.5 μm, and/or b) the diameter d(50) is of less than or equal to 15.0 μm, preferably of less than or equal to 10.0 μm, and/or c) the diameter d(90) is of less than or equal to 30.0 μm, preferably of less than or equal to 25.0 μm.

3. The emulsifying composition according to claim 1, wherein the solid cyclodextrin particles have a volumetric particle size distribution, measured by laser diffraction granulometry, having a coefficient of variation of less than or equal to 100%, preferably of less than or equal to 90%, and most preferably of less than or equal to 73%.

4. The emulsifying composition according to claim 1, wherein the water-in-oil emulsifier of natural origin is selected from emulsifiers having a hydrophilic-lipophilic balance (HLB) of between 1.5 and 6.0, preferably between 2.0 and 5.0, and better still between 3.0 and 5.0.

5. The emulsifying composition according to claim 1, wherein the average HLB of the overall emulsifying system of said composition is of less than 8, preferably of less than or equal to 7

6. The emulsifying composition according to claim 1, wherein the emulsifier of natural origin is present in the emulsifying composition in an emulsifier/cyclodextrin ratio of between 0.01:1 and 1:1, preferably of between 0.05:1 and 0.5:1, more preferably of between 0.10:1 and 0.35:1 and better still of between 0.15:1 et 0.30:1.

7. The emulsifying composition according to claim 1, wherein said cyclodextrin is selected from the alpha-, beta- and gamma-cyclodextrins, preferably is a native beta-cyclodextrin.

8. The emulsifying composition according to claim 1, wherein the emulsifier of natural origin is a water-in-oil emulsifier selected from non-ethoxylated polyol fatty esters, in particular from glycerol, polyglycerol, sorbitol, sorbitan, anhydrohexitol fatty esters, preferably from isosorbide, mannitol, xylitol, erythritol, maltitol, sucrose, glucose, polydextrose, hydrogenated glucose syrup, dextrin and hydrolyzed starch fatty esters.

9. The emulsifying composition according to claim 1, wherein the water-in-oil emulsifier of natural origin is selected from non-ethoxylated polyol fatty esters obtained from fatty acids or by transesterification from oil or oil mixtures.

10. The emulsifying composition according to claim 1, comprising: 1) 40% to 95% of at least one cyclodextrin in the form of solid particles, said particles having a volumetric average particle size d(4.3), measured by laser granulometry, of between 2 and 20 μm, preferably between 3 and 12 μm, and more preferably between 4 and 8 μm, 2) 5% to 40% of at least one emulsifier of natural origin selected from water-in-oil-type emulsifiers, having a hydrophilic-lipophilic balance of less than 8, most preferably of less than or equal to 7 3) And 0% to 40% of at least one polyol.

11. A liquid emulsion, preferably oil-in-water Pickering, wherein said liquid emulsion comprises at least one cyclodextrin in the form of solid particles, said particles having a volumetric average particle size d(4.3) of between 2 and 20 μm, preferably between 3 and 12 μm, and more preferably between 4 and 8 μm, and at least one emulsifier of natural origin selected from water-in-oil emulsifiers, having a hydrophilic-lipophilic balance of less than 8, most preferably of less than or equal to 7, in an emulsifier/cyclodextrin ratio of between 0.01:1 and 1:1, preferably of between 0.15:1 et 0.30:1.

12. The emulsion according to claim 11, wherein said emulsion presents itself in the form of a fatty phase dispersed in an aqueous phase, said dispersed fatty phase presenting itself in the form of droplets with an average size in number of less than 30 μm, preferably of less than or equal to 10 μm.

13. The composition according to claim 1, having a viscosity greater than 3,000 mPa.Math.s at 25° C., preferably greater than 5,000 mPa.Math.s at 25° C.

14. A method for manufacturing a liquid emulsion, preferably oil-in-water Pickering, comprising the following steps: a) dispersing, in an aqueous phase, an emulsifying composition comprising at least one cyclodextrin in the form of solid particles, said particles having a volumetric average particle size d(4.3) measured by laser granulometry, of between 2 and 20 μm, preferably between 3 and 12 μm, and more preferably between 4 and 8 μm, and at least one emulsifier of natural origin selected from water-in-oil-type emulsifiers, having a hydrophilic-lipophilic balance of less than 8, most preferably of less than or equal to 7, in an emulsifier/cyclodextrin ratio of between 0.01:1 and 1:1, preferably between 0.15:1 and 0.30:1, b) adding a fatty phase to the mixture obtained in step a) in an amount of between 10 and 65% by weight, with respect to the total weight of the composition, under stirring to enable the dispersion of the fatty phase in the aqueous phase in the form of droplets with an average size of less than or equal to 30 μm, preferably of less than or equal to 10 μm.

15. A combined use of at least one cyclodextrin in the form of solid particles having a volumetric average particle size d(4.3) measured by laser granulometry, of between 2 and 20 μm, preferably between 3 and 12 μm, and more preferably between 4 and 8 μm, and of at least one emulsifier of natural origin selected from water-in-oil-type emulsifiers, having a hydrophilic-lipophilic balance of less than 8, most preferably of less than or equal to 7, in a liquid emulsion for cosmetic use to provide said emulsion with a softer and smoother feel, make said emulsion easier to spread, and to reduce or eliminate pilling

Description

EXAMPLES

[0093] The invention will be better understood with the aid of the non-limiting exemplary embodiments described hereinafter.

Example 1: Emulsion

[0094] An oil-in-water emulsion embodied according to the invention was compared with a so-called “reference” oil-in-water emulsion, realized outside of the invention, both prepared according to the composition of Table 1.

TABLE-US-00001 TABLE 1 Composition of the emulsion Component/INCI name Mass % Sunflower oil/Helianthus annuus seed oil 30 Beta-cyclodextrin/Cyclodextrin 2.5 Sorbitol (powdered) 1 Polyglyceryl-3 diisostearate 0.5 Demineralized water/Aqua 64.3 Xanthan gum/Xanthan gum 0.7 Preservative 1

[0095] The reference emulsion is obtained by using a beta-cyclodextrin marketed under the name “Beauté by Roquette® CD102” by the applicant. The emulsion according to the invention is obtained by using this same beta-cyclodextrin previously dry ground to have a volumetric average size d(4.3) of less than 20 μm; the beta-cyclodextrin thus obtained is qualified as “ultra-fine”. The granulometric characteristics of these two beta-cyclodextrins are presented in Table 2.

TABLE-US-00002 TABLE 2 granulometric characteristics of the beta-cyclodextrins Beta-cyclodextrin Beta-cyclodextrin according “Beauté by Roquette ® to the invention, so-called CD102” (reference) “ultra-fine” d(4.3) (μm) 94.83 11.43 d10 (μm) 21.81 2.378 d50 (μm) 85.81 9.716 d90 (μm) 182.2 22.85 CV 64.7% 72.3%

[0096] The protocol for preparing the emulsions is the following. First a thickening agent is dispersed, in this case xanthan gum, in water at 40° C. under stirring with deflocculation blades at 500 revolutions per minute. Separately, the beta-cyclodextrin is mixed with the sorbitol and the polyglyceryl-3 diisostearate. This mixture is then added into the water containing the thickening agent, under stirring at 1000 revolutions per minute, in order to obtain an aqueous phase.

[0097] The amount of beta-cyclodextrin is set at 2.5% by weight of the emulsion for the two emulsions.

[0098] The sunflower oil constitutes the oily phase, it is heated to 40° C.

[0099] The oily phase is thus emulsified in the aqueous phase at 40° C. under stirring at 3000 revolutions per minute for 20 minutes.

[0100] It is left to cool and when at room temperature (20° C.), a phenoxyethanol-based preservative is then added.

[0101] For each of the emulsions, physical and chemical characteristics are measured, namely the viscosity and the average size of the droplets, and sensory characteristics are measured, namely fluidity, slipperiness, spreadability, greasiness, softness, squeakiness, penetrability, smoothness and pilling.

[0102] Viscosity is measured using a Brookfield DV-II+Pro viscometer. A fixed-size moving part (SP2 to SP7 moving parts used according to the viscosity levels in accordance with apparatus instructions) is rotated at a speed of 20 revolutions per minute in contact with the product sample. The resistance of the product to this rotational movement is registered during one minute and converted into millipascal-second. For each sample, the viscosity is measured three times and the arithmetic mean of three values is retained.

[0103] The average size of the droplets is determined by carrying out the arithmetic mean of the droplet sizes measured with an optical microscope at ×10 magnification, on a representative number of droplets, typically at least 10 droplets. The microscope used is a LEICA DMLS.

[0104] The sensory characteristics are evaluated by a panel of ten people who are experts in analyzing the texture of cosmetic products.

[0105] When spreading the product, two descriptors are evaluated. The examination of the product is done under the lamp, after having deposited 50 to 100 μL of the product under examination on the hand, while it is spread for 10 turns. [0106] The smoothness descriptor is evaluated between the 2nd and 5th turn. The fingers slide well over the skin. The product is perceived as a powdery substance on the skin. [0107] Spreading is evaluated by examining the product after having placed 50-100 μl of the product on the hand, while it is spread for 10 turns, under a lamp. Spreading is highest when there is little resistance to movement between the 5th and the 10th turn on the hand.

[0108] The following descriptors are evaluated after 10 turns are carried out.

[0109] For the following two descriptors, the examination is carried out under a lamp, on the skin, 1 minute after spreading 50 to 100 μl of the product. [0110] The softness descriptor is evaluated by sliding over the skin: a dry and slippery sensation is felt. [0111] The squeakiness descriptor is evaluated by rubbing the thumb with the index finger, resistance is felt, and a squeaky sound is heard.

[0112] For the following two descriptors, the examination is carried out under the lamp, on the skin, 2 minutes after spreading 50 to 100 μl of the product. [0113] The penetration descriptor of the product is evaluated by sliding over the skin. A panel of evaluators then evaluates the amount of product residue recovered. [0114] The pilling is evaluated by carrying out a mechanical rubbing action on the skin, the product leads to the formation of pills.

TABLE-US-00003 TABLE 3 improved sensory perceptions with respect to the reference emulsion Emulsion according to the invention, with “ultra-fine” beta- Sensory cyclodextrin, with respect to the emulsion with Beauté by perception Roquette ® CD102 Smooth Smoother Spread Easier Softness Softer feel Squeaky Notably less squeaky Penetrating Faster penetration Pilling No pilling or less pilling

[0115] The criteria for improved sensory properties in the emulsion according to the invention are: fluidity, smoothness, spreadability, greasy, softness, squeaky, penetrability, pilling.

Example 2: Sunscreen

[0116] The sensory profile of a sunscreen formulation prepared with a beta-cyclodextrin with an average diameter of 200 μm (Beauté by Roquette® CD102 of example 1) or with a beta-cyclodextrin with a volumetric average particle size of 11.43 μm (ultra-fine beta-cyclodextrin of example 1), according to the operating mode hereinafter.

[0117] First, phase A1 is prepared according to the composition of Table 4: the Sunsphere powder is dispersed in the water and the Cetiol C5, it is then heated to 55° C. under stirring at 2000 rpm with a rotor-stator for 15 minutes.

TABLE-US-00004 TABLE 4 Composition of phase A1 % m of Phase Trade name Supplier INCI name the total A1 Demineralized Cooper Aqua 36.44 water EDETA BD AMI Chimie Disodium EDTA 0.10 Sunsphere Dow Styrene/acrylate 5.00 powder (Univar) copolymer Cetiol C5 AMI Chimie Coco-caprylate 1.00

[0118] Separately, phase A2 is prepared by weighing all the ingredients in a cup, then it is added to phase A1 under stirring with rotor-stator at 2000 rpm for 15 minutes. Phase A1+A2 is stored at 70° C. under stirring.

TABLE-US-00005 TABLE 5 composition of phase A2 % m of Phase Trade name Supplier INCI name the total A2 Sepinov WEO Seppic Hydroxymethyl 0.20 Acrylate/Sodium Acryloyldimethyl Taurate Copolymer Microcare PHC Thor Glycerin & 1.00 Chlorphenesin & Phenoxyethanol Xanthan gum Interchimie Xanthan gum 0.30 Glycérine codex Cooper Glycerin 3.00 Romol AFSK Saci cfpa Potassium cetyl 0.30 phosphate

[0119] Phase B1 is then prepared by heating to 70° C. under magnetic stirring for 10 minutes according to the composition of Table 6.

TABLE-US-00006 TABLE 6 composition of phase B1 % m of Phase Trade name Supplier INCI name the total B1 Cetiol C5 AMI Chimie Coco-caprylate 2.00 Cocoate BG Gattefossé Butylene glycol cocoate 2.00 Parsol 1789 IES Butyl 5.00 Ingrédients MethoxyDibenzoylMethan Parsol EHS IES Ethylhexyl Salicylate 5.00 Ingrédients Parsol MCX IES Ethylhexyl 7.50 Ingrédients Methoxycinnamate Parsol HMS IES Homosalate 9.00 Ingrédients Solastay S1 Azelis Ethylhexyl 3.00 methoxycrylene Hallbrite Azelis Butyl Octyl Salycilate 4.00 BHB Tinogard TL AMI Chimie Benzotriazolyl Dodecyl P- 1.00 Cresol Covanol Red Sensient Iron oxides (CI77491) & 0.12 ON 3780 Octyldodecanol & Stearic acid & Magnesium hydroxide & Aluminium hydroxide & Sorbitan oleate Covanol Sensient Iron oxides (CI77492) & 0.53 Yellow ON Octyldodecanol & Stearic 1782 acid & Magnesium hydroxide & Aluminium hydroxide & Sorbitan oleate Oleic Oléon Helianthus annuus seed 3.00 sunflower oil oil

[0120] Storing phase B1 at 70° C. under stirring, phase B2 is added, prepared separately and constituted according to the composition of Table 7, and it is kept under stirring for 10 minutes, after which the phase B1+B2 is emulsified in phase A.

TABLE-US-00007 TABLE 7 composition of phase B2 % m of Phase Trade name Supplier INCI name the total B2 Beauté by Roquette Cyclodextrin 2.5 Roquette ® CD102 Frères Plurol Gattefossé Polyglyceryl 3- 0.5 diisostearate Neosorb Roquette Sorbitol 1 Frères

[0121] To emulsify the phase B1+B2 in phase A, the entirety of phase B1+B2 is poured into phase A at 55° C. under stirring with rotor-stator at 2500 rpm, which is then maintained for 5 minutes at 55° C., and for 10 minutes under cold water bath. The speed is reduced to 1200 rpm and stirring continues until the emulsion is at room temperature under cold water bath.

[0122] Phase C is then added, it is then colored with phase D.

TABLE-US-00008 TABLE 8 composition of phases C and D % m of Phase Trade name Supplier INCI name the total C Plouf RL G Robertet Perfume 0.50 113 23705 D Covarine Sensient CI 77891 (and) Glycerin 4.00 white WN (and) Xanthan Gum (and) 9787 Sodium Citrate (and) Aqua Covarine Sensient CI 77499 & Glycerin & 0.01 black WN Xanthan gum & Sodium 9798 citrate & Aqua

[0123] A tinted and perfumed cream is thus obtained. When it is applied on the skin, the cream pills, it is comfortable but a squeaky effect is noted when it is spread.

[0124] A sunscreen is then prepared according to the previous protocol by substituting “Beauté by Roquette® CD102” for the “ultra-fine” beta-cyclodextrin of example 1. The cream is applied on the skin: there is no pilling, the cream is more comfortable. A slight squeaky effect persists at the end of the penetration of the cream, but it is significantly less present than with the reference formulation comprising the beta-cyclodextrin “Beauté by Roquette® CD102”.