Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
  • A61K8/72—Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds
  • A61K8/73—Polysaccharides
  • A61K8/738—Cyclodextrins
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/02—Cosmetics or similar toiletry preparations characterised by special physical form
  • A61K8/04—Dispersions; Emulsions
  • A61K8/06—Emulsions
  • A61K8/062—Oil-in-water emulsions
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
  • A61K8/30—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds
  • A61K8/33—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds containing oxygen
  • A61K8/34—Alcohols
  • A61K8/345—Alcohols containing more than one hydroxy group
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61Q—SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
  • A61Q19/00—Preparations for care of the skin
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K2800/00—Properties of cosmetic compositions or active ingredients thereof or formulation aids used therein and process related aspects
  • A61K2800/40—Chemical, physico-chemical or functional or structural properties of particular ingredients
  • A61K2800/49—Solubiliser, Solubilising system

Definitions

• Emulsifying composition and process for producing a Pickering O / W emulsion composition Emulsifying composition and process for producing a Pickering O / W emulsion composition
• the present invention relates to an emulsifying composition of plant origin ready for use and directly usable cold which finds applications particularly in the field of cosmetics.
• This composition is self-sufficient and directly stabilizes an emulsion without the necessary addition of a co-emulsifier.
• This emulsifying composition makes it possible in particular to easily produce very fine O / W emulsions with various textures, which are very compatible with the skin and furthermore have a dry, fresh, silky and non-greasy feel, even with a high fat content. in the emulsion.
• An emulsion is a dispersion of a liquid (or a material made liquid) in fine droplets in another liquid immiscible with the first. It has a macroscopically homogeneous appearance but appears heterogeneous under the microscope.
• the liquid in the form of droplets is called dispersed phase (or discontinuous), while the other liquid is called dispersant phase (or continuous).
• an emulsion is composed of water and oil and two phases (single emulsion): a hydrophilic phase (aqueous) and a lipophilic phase (fat).
• emulsions most commonly encountered are emulsions comprising a lipophilic phase dispersed in a continuous aqueous phase and are called oil-in-water (O / W) emulsions, as opposed to water-in-oil (W / O) emulsions.
• O / W oil-in-water
• W / O water-in-oil
• EP 0 685 227 proposes a very complex system of antisolar cosmetic compositions, comprising an aqueous continuous phase, a protective system capable of filtering UV rays, a surfactant, and organic solvents (alcohols and lower polyols). and at least one polymer or more particularly a crosslinked copolymer (alkyl acrylates, vinyl acetate).
• Document FR 2 858 777 describes an oil-in-water emulsion containing at least one fatty substance (esters of fatty acids, waxes, butters, natural oils - vegetable, animal, of marine origin), synthetic or mineral, hydrogenated oils and mixtures thereof), at least one surfactant (ethoxylated polyglycerol fatty acid esters, alcohol ethoxylates), at least one co-surfactant and water.
• fatty substance esters of fatty acids, waxes, butters, natural oils - vegetable, animal, of marine origin
• surfactant ethoxylated polyglycerol fatty acid esters, alcohol ethoxylates
• surfactants in products intended to be applied in humans or animals, whether in topical, oral or other forms, can be problematic. Indeed, surfactants can damage cell membranes. Thus, efforts are made, particularly in the cosmetic field, to reduce the potentially harmful effects of surfactants or eliminate the use of surfactants.
• an object of the present invention is to provide a composition which, in the presence of water, is capable of forming, even in a cold process, a stable emulsion by adding oil or fat. It eliminates the use of conventional surfactants, of petroleum origin and non-biodegradable, including no longer use derivatives of glycols and ethoxylated derivatives. From this point of view, the composition according to the present invention also makes it possible to manufacture Pickering type emulsions. Emulsions of this type are devoid of surfactant and are stabilized by colloidal particles such as usually silicas which are placed at the interfaces of the continuous phase and the dispersed phase.
• these colloidal particles are organic particles consisting of inclusion complexes between at least one cyclodextrin and at least one fatty molecule. These particles are very advantageously compatible with the skin or the hair and do not damage the cellular membranes of animal nature.
• Another object of the present invention is to provide a composition of 100% natural origin.
• the natural origin of ingredients used to formulate everyday products such as cosmetic compositions is today a major challenge, not only vis-à-vis the safeguarding and protection of our environment but also for the well being consumers.
• the composition according to the present invention makes it possible to replace the traditional emulsifiers, in particular ethoxylated emulsifiers, which today are sought to be substituted for environmental issues (poor biodegradability) and safety (ethylene oxide is toxic and flammable).
• Another object of the present invention is to provide a ready-to-use composition, allowing the formulator a very simple implementation, with a minimum energy input, especially by introducing all the ingredients into the same tank or reactor (formulation called "one pot” in Anglo-Saxon language).
• the composition which is the subject of the present invention is advantageously usable according to a "cold process", that is to say even at ambient temperature, unlike many solid or conventional solid emulsifiers. pastes such as waxes that require a rise in temperature for their implementation (ingredient requiring to be melted and usable "hot”).
• cold process it is meant that the emulsifying composition can be carried out directly by dispersion in water at a water temperature below 45 ° C, better below 35 ° C and more preferably at room temperature.
• Another object of the present invention is to provide a composition for cosmetic use broad spectrum, that is to say, versatile from the point of view of the end products envisaged: from this point of view, the composition according to the invention can be used in products as diverse as lotions, creams, gels, milks ....
• said composition is advantageously non-irritating and non-allergic to the skin. It also offers the advantage of not depending on the pH or the presence of electrolytes: in other words, its emulsifying capacity is not affected by the pH of the medium, or by the presence of mono salts, di or trivalent.
• another object of the present invention is to provide a composition for cosmetic use, offering a wide range of sensory properties of interest, such as in particular a feeling of freshness in the epidermis or a creamy texture.
• the emulsifying composition according to the invention allows easy realization of O / W emulsions that are both very stable and very fine, with modulable textures and having a fresh, silky and non-greasy feel, even for high levels of dispersed fatty phase. It is thus possible to obtain emulsions having a good emollient effect on the skin as well as a good moisturizing effect of the upper layers of the epidermis.
• the main object of the present invention which consists of a emulsifying composition, in particular for cosmetic use, suitable for obtaining an oil-in-water emulsion (O / W), comprising:
• W / O emulsifier having a hydrophilic-lipophilic balance (HLB) of less than 8.
• HLB hydrophilic-lipophilic balance
• the calculation of the HLB takes into account the molecular masses of the hydrophilic parts and the molecular mass of the molecule considered and can be obtained according to the following equation:
• Mass excee be part of mirroring
• cyclodextrin refers to and includes any of otherwise known cyclodextrins, such as native and unsubstituted cyclodextrins containing from 6 to 12 glucose units linked by covalent bonds between carbons 1 and 4 , and in particular alpha-, beta- and gamma-cyclodextrins containing respectively 6, 7 and 8 units of glucose.
• cyclodextrin derivatives ie molecules of which at least part of the hydroxyl groups OH has been converted into groups OR, where R generally denotes an alkyl group.
• the cyclodextrin derivatives include, in particular, methylated and ethylated cyclodextrins, but also those substituted with a hydroxyalkyl group such as hydroxypropylated and hydroxyethylated cyclodextrins.
• Preferred cyclodextrins according to the present invention are alpha-, beta- and gamma-cyclodextrins, with native beta-cyclodextrin being most preferred.
• the cyclodextrin may especially be in the form of a crystalline powder, pseudocrystalline or amorphous.
• emulsifier W / H of natural origin denotes any molecule derived from renewable resources, in particular extracted or secreted by plants, microorganisms or algae and able to allow after physical modification, chemical or enzymatic, obtaining a water-in-oil emulsion W / O or to promote stability. Under this definition, therefore, are included products called co-emulsifiers E / H.
• the effectiveness of an emulsifier is known to be primarily related to its solubility in each of the two phases.
• the phase in which the emulsifier is the most soluble forms the continuous phase of the emulsion.
• a water-soluble emulsifier stabilizes an oil-in-water O / W emulsion.
• the emulsifying composition according to the present invention which can be used directly in the cold state to prepare O / W emulsions, has a particularly low solubility in water, of the order of only 1.8% at 25 ° C. when it is retained. according to the preferred mode, as cyclodexrin, beta-cyclodextrin.
• the W / O emulsifier of natural origin having a hydrophilic-lipophilic balance (HLB) of less than 8 is preferably present in the emulsifying composition in a ratio of between 0.01 and 1 part, preferably between 0.05 and 0.5 parts, more preferably between 0.10 and 0.35 parts and more preferably between 0.15 and 0.30 for 1 part by weight of cyclodextrin.
• HLB hydrophilic-lipophilic balance
• this emulsifier of natural W / O origin may be chosen from the following products, provided that they satisfy the condition on the HLB above: the non-ethoxylated fatty esters of polyols, and in particular from non-ethoxylated fatty esters of glycerol, polyglycerols, sorbitol, sorbitan, anydrodrohexitols such as in particular isosorbide, mannitol, xylitol, erythritol, maltitol, sucrose, glucose, polydextrose, hydrogenated glucose syrups, dextrins and hydrolysed starches.
• the non-ethoxylated fatty esters of polyols and in particular from non-ethoxylated fatty esters of glycerol, polyglycerols, sorbitol, sorbitan, anydrodrohexitols such as in particular isosorbide, mannitol, xy
• the W / O emulsifier of natural origin is preferably chosen to be naturally biodegradable in a natural hydrated medium. It can be in particular non-ethoxylated fatty esters of polyols obtained from fatty acid or by trans-esterification from oil or oil mixtures.
• the fatty acids used comprise from 8 to 22 carbon atoms, preferably from 10 to 18 carbon atoms, and in particular from 12 to 18 carbon atoms. These acids can be linear or branched, saturated or unsaturated, possess one or more side hydroxyl functions.
• the oils may be saturated or unsaturated, from liquid to solid at room temperature, and optionally have hydroxyl functional groups, preferably having an iodine number between 1 and 145, and in particular from 5 to 105.
• the W / O emulsifier of natural origin can also be chosen from products that are naturally biodegradable in a hydrated natural medium, with in particular a hydrophilic-lipophilic balance (HLB) of between 1.5 and 6, preferably between 2 and 5 and better still between 3 and 5.
• HLB hydrophilic-lipophilic balance
• the W / O emulsifier of natural origin may in particular be chosen from fatty esters of glycerol, and in particular from oleates, stearates, glycerol isostearates, for example the following products: glyceryl laurate HLB 5.2, glyceryl oleate HLB 4 such as IMWITOR 948, Lubrizol Schercemol's Schercemol GMIS HLB 3.5 glyceryl isostearate and Sympatens-GMS glyceryl monostearate HLB 3.5.
• fatty esters of sorbitan or sorbitol in particular from laurates, palmitate, oleates, stearate, sorbitan isostearates, for example the sorbitan trioleate Kosteran-O / 3 HLB 1.8; sorbitan oleate MONTANE 80 VG or SPAN 80-LQ- (RB) or Kosteran-O / 1 HLB 4.3; sorbitan isostearate Kosteran-1/1 HLB 4.3, sorbitan stearate Kosteran-S / 1 HLB 4.7; sorbitan monopalmitate HLB 6.6; sorbitan laurate Kosteran L / l HLB 8.6,. It may also be chosen from sucrose fatty esters, for example Sisterna SP60-C sucrose distearate, Sisterna SP10-C sucrose polystearate, and HLB 6 sucrose cocoate.
• sucrose fatty esters for example Sisterna SP60-C sucrose distearate
• the W / O emulsifier of natural origin may in particular be chosen from the polyglycerol esters and preferably from the esters resulting from the reaction of polyglycerols comprising from 2 to 12 glycerol units, preferably from 3 to 6 glycerol units with at least one partially hydrogenated or non-hydrogenated vegetable oil having an iodine number of between 1 and 15, and in particular of 5 to 10.
• polyglyceryl-4 isostearate HLB 3 (as HYDRIOL ® ERP HYDRIOR), polyglyceryl-10 pentaoleate HLB 3.5 (as Decaglyn 5-OV), polyglyceryl-6 polyricinoleate (as HEXAGLYN PR-15), polyglyceryl-2 sesquiisostearate HLB ⁇ 4 (as Hostcerin IMB Clariant and Dermofeel ® GO soft Evonik Dr.
• polyglyceryl-4 isostearate HLB 3 (as HYDRIOL ® ERP HYDRIOR)
• polyglyceryl-10 pentaoleate HLB 3.5 (as Decaglyn 5-OV)
• polyglyceryl-6 polyricinoleate (as HEXAGLYN PR-15)
• polyglyceryl-2 sesquiisostearate HLB ⁇ 4 (as Hostcerin IMB Clariant and Dermofeel ® GO
• polyglyceryl-3 ricinoleate HLB 3.5 polyglyceryl-3 polyricinoleate HLB 4 (as Imwitor 600), polyglyceryl -3 polyricinoleate HLB: ⁇ 4 (as Dermofeel ® PGPR Evonik Dr. Straetmans GmbH), polyglyceryl-2 sesquioleate HLB 4 (as Dermofeel ® GO soft Evonik Dr.
• polyglyceryl-2 diisostearate (as Emulpharma ® PG20 of Res Pharma), polyglyceryl-3 diisostearate HLB: 5.5 (such as Plurol ® Diisostearique CG from Gattefossé, Lameform ® TGI from BASF, IMWITOR ® PG3 DIS from IOI Oleo GmbH, Cithrol TM PG32IS from Croda, DUB ISO G3 from Stéarinerie Dubois, ® Polyaldo 3-1-S Lonza, 7245 Jolee of OIéon and MASSOCARE PG3D Masso), polyglyceryl-3 oleate HLB 6.2 (such as MUL PGO-31 Ivanhoe Industries), polyglyceryl-3 LB 7.2 monostearate, polyglyceryl-4 oleate HLB 8 (as HYDRIOL ® PGM0.4 of HYDRIOR), polyglyceryl-5 diole
• the preferred ester is that resulting from the reaction of polyglycerol-3 and isostearic acid (INCI name: polyglyceryl-3 diisostearate).
• the W / O emulsifier of natural origin may consist of mixtures of fatty esters, in particular of polyglycerol fatty esters, of sorbitan fatty esters or of glucose esters, such as in particular mixtures such as the Nikkomulse WO products.
• Straetmans polyglyceryl-3 polyricinoleate, sorbitan sesquioleate, cetyl ricinoleate, glyceryl caprate, cera alba, magnesium stearate, aluminum stearate
• Ecomuls 2 in 1 from Stahla-Tec (glyceryl oleate, polyglyceryl-3-polyricinoleate, olea europaea (olive) oil unsaponifiables)
• HIPEgel Olea from Alchemy (glycerin, isopropyl palmitate, water sucrose stearate, sucrose laurate).
• the emulsifying composition according to the invention also makes it possible to obtain interesting sensory effects, such as a particular texture or a sensation of freshness, according to the proportions used.
• each of the various constituents of the present emulsifying composition according to the invention can be integrated in a different phase, before it is carried out in emulsification.
• the various compounds of the present composition according to the invention are mixed together to form what will be referred to hereinafter by the term premix, said premix may be added to one or the other of the two immiscible phases for allow the formation of an O / W emulsion.
• the invention advantageously allows these two embodiments with the same compounds, which allows an increased margin of maneuver and simplified use.
• Such an emulsifying composition according to the invention has the advantage of being completely of natural origin, and of being usable according to a cold process and in particular at room temperature. Said composition according to the invention is for cosmetic use and, as such, is not sensitive to reasonable pH variations or medium salinity, is not irritating and is not likely to cause allergies, in particular skin.
• the composition according to the invention can be used to produce any type of emulsion, including Pickering type emulsions, and is therefore suitable for a wide variety of purposes: creams, milks, serums, lotions, etc.
• the emulsifying composition according to the invention makes it possible to produce Pickering-type emulsions which can advantageously be stabilized by organic particles compatible with the skin or the hair. It may additionally comprise other products capable of forming or stabilizing Pickering emulsions such as silicas and octenylsuccinates starches in the form of calcium or aluminum salts.
• the emulsifying composition also comprises at least one polyol.
• the polyols referred to by the present application are all the polyols known elsewhere, and in particular maltitol, mannitol, xylitol, erythritol, sorbitol, glycerol, glycerol and sorbitol being the preferred polyols.
• this polyol is crystallized or is in the form of a powder.
• the emulsifying composition especially for cosmetic use and suitable for obtaining an oil-in-water (O / W) type emulsion according to the present invention may comprise in particular:
• this emulsifying composition according to the present invention is characterized in that it contains, in% by weight:
• this composition according to the present invention is characterized in that it contains, in% by weight:
• composition of Pickering O / W emulsion type in particular for cosmetic use, characterized in that it contains, for 1 part by weight of at least one cyclodextrin, between 0.01 and 1 part, preferably between 0.05 and 0.5 part, more preferably between 0.10 and 0.35 part and better still between 0.15 and 0.30 part of at least one emulsifier w / o of origin natural, the latter being preferably chosen from a non-ethoxylated ester of polyols or at least one naturally biodegradable product in a natural medium hydrated having a hydrophilic-lipophilic balance (HLB) of less than 8.
• HLB hydrophilic-lipophilic balance
• the Pickering O / W emulsion composition according to the invention may also comprise a fatty phase which may be at room temperature (25 ° C.), liquid, for example vegetable oils, or solid, as in the case of waxes. .
• This liquid fatty phase may be of mineral, animal, vegetable or synthetic origin and be composed of hydrocarbon oils or possibly silicone oils.
• hydrocarbon-based oil means an oil formed essentially or even consisting of carbon and hydrogen atoms and optionally oxygen, nitrogen, which may contain alcohol, ester, ether, carboxylic acid or amine groups. and / or amide.
• this composition contains one or more liquid oils at room temperature (25 ° C.), preferably at least one non-volatile liquid oil.
• nonvolatile liquid oil is meant an oil that can remain on the skin at room temperature, at atmospheric pressure for at least one hour.
• the liquid fatty phase advantageously comprises one or more non-volatile oils which provide an emollient effect on the skin.
• fatty esters such as cetearyl isononoate, isotridecyl isononoate, isostearyl isostearate, isopropyl isostearate, isopropyl myristate, isopropyl palmitate, butyl stearate.
• oils may be hydrocarbon or silicone type oils such as paraffin oil, squalane, petroleum jelly, dimethylsiloxanes and mixtures thereof.
• the liquid fatty phase may also optionally comprise volatile oils.
• volatile oil is meant an oil capable of evaporating from the skin in less than one hour at room temperature and atmospheric pressure.
• the volatile oils may for example be chosen from silicone oils or triglycerides of short fatty acids to reduce the greasy feel.
• the Pickering O / W emulsion composition according to the invention contains only oils of renewable origin and in particular oils or butters of vegetable origin, preferably refined. These oils and butters agree perfectly with the emulsifier system object of the invention in the sense that they make it possible to obtain very stable emulsions with a high whiteness and an easily adjustable viscosity.
• the emulsifying composition according to the invention advantageously makes it possible to prepare O / W emulsions with very high oil contents. This type of oil-rich O / W emulsions is usually difficult to obtain in stable form over time with conventional emulsifiers.
• the oil content of the final O / W emulsion is preferably from 10 to 65% by weight, and preferably from 20 to 55% by weight.
• Vegetable or plant-based oils for example sunflower oil and isopropyl palmitate, make it possible in particular to obtain stable emulsions which do not give rise to creaming or phase shift.
• composition according to the invention may furthermore comprise a rheology agent such as, in particular, a thickener of the aqueous phase, a gelling agent or a suspending agent, such as, for example, gums derived from plants such as gum arabic or Konjac gum.
• a rheology agent such as, in particular, a thickener of the aqueous phase
• a gelling agent or a suspending agent such as, for example, gums derived from plants such as gum arabic or Konjac gum.
• guar gum or their derivatives gums extracted from algae such as alginates or carrageenans; gums from microbial fermentation such as xanthans, mannan, scleroglucans or their derivatives; cellulose and its derivatives such as carboxymethylcellulose or hydroxyethylcellulose; starch and its derivatives, in particular modified starches, in particular acetylated, carboxymethylated, octenylsuccinated or hydroxypropylated starches; synthetic polymers such as polyacrylic acids or carbomers.
• the composition according to the invention comprises a rheology agent chosen from naturally occurring plant-derived or fermentation-modified polysaccharides, optionally modified.
• xanthan and its derivatives make it possible to obtain O / W emulsions with very fine droplet sizes, even used at a content of less than 1% by weight of the total emulsion.
• the emulsions obtained by employing the emulsifying composition according to the invention preferably have a drop size of less than 10 ⁇ m.
• drop size of the emulsion is meant the average diameter of the droplets of dispersed fatty phase suspended in the aqueous phase.
• a small drop size increases the stability of the emulsion by reducing the emulsion flocculation rate, and thus the rate of phase separation.
• the drop size depends on a large number of parameters and, as such, is a characteristic that should be controlled and is not intrinsic to the formulation of the emulsifier system.
• the size of the droplets is measured using a LEICA DMLS optical microscope at x10 magnification.
• composition according to the invention may further comprise a preservative chosen from benzyl alcohol, dehydroacetic acid and mixtures thereof.
• the composition according to the invention preferably has a viscosity greater than 3000 mPas at 25 ° C, preferably greater than 5000 mPas at 25 ° C.
• the viscosity is measured using a Brookfield DV-11 + Pro viscometer rotated at a rate of 20 rotations per minute in contact with the product sample. The resistance of the product to this rotational motion is recorded for one minute and converted to mPascal second. For each sample, the viscosity is measured three times and the arithmetic mean of the three values is retained.
• sensory descriptors and a corresponding sensory evaluation protocol are used in 5 steps. These 5 steps correspond to the different phases of application of a care product: appearance, handling, spreading after 1 minute, after 2 minutes. During these 5 phases, several sensory descriptors are evaluated by a panel of evaluators who assign a score ranging from 0 to 10.
• the composition according to the invention preferably has a whiteness descriptor greater than 8.
• the whiteness descriptor is defined by the color palette of FIG. 1. The product is examined under the lamp and compared to the color palette by a panel. appraisers.
• composition according to the invention preferably has a gloss descriptor greater than or equal to 8.
• the brightness is defined by the propensity of the product to reflect light.
• composition according to the invention preferably has a spreading descriptor greater than 8.
• the spreading is evaluated by examining the product after having deposited on the hand 50 to 100 ml of the product, during its spreading in 10 rotations, under a lamp. Sprawl is all the more important as there is little resistance to movement between the 5th and 10th turn on the hand.
• composition according to the invention preferably has a film-forming descriptor greater than 8.
• the film-forming descriptor corresponds to the propensity of the product to form a continuous film by sliding on the skin 2 minutes after 10 rotations.
• Another subject of the present invention consists in a method for manufacturing a composition of the Pickering O / W emulsion type, in particular for cosmetic use, comprising the following steps: a) the dispersion in an aqueous phase of an emulsifying composition comprising at least one cyclodextrin and at least one W / O emulsifier of natural origin, the latter being present in a ratio of between 0.01 and 1 part, preferably between 0.05 and 0.5 part, more preferably between 0, 10 and 0.35 parts and more preferably between 0.15 and 0.30 parts for 1 part by weight of at least this cyclodextrin; this w / o emulsifier of natural origin can be chosen in particular from at least one non-ethoxylated fatty ester of polyols or at least one naturally biodegradable product having a hydrophilic-lipophilic balance (HLB) of less than 8,
• HLB hydrophilic-lipophilic balance
• step b) the addition to the mixture obtained in step a) of a fatty phase, preferably in an amount of between 10 and 65% by weight, and preferably of the order of 20 to 55% by weight relative to the final weight of the emulsion, under mechanical agitation sufficient to allow the dispersion of the fatty phase into fine droplets in the aqueous phase and obtaining an O / W emulsion having a drop size of less than 10 .mu.m.
• the process according to the invention for the manufacture of a Pickering O / W emulsion composition comprising the following steps: a) the dispersion in a fatty phase of an emulsifying composition comprising at least at least one cyclodextrin and at least one W / O emulsifier of natural origin, the latter being present in a ratio of between 0.01 and 1 part, preferably between 0.05 and 0.5 part, more preferably between 0.10 and 0.35 parts and more preferably between 0.15 and 0.30 parts per 1 part by weight of at least this cyclodextrin; this w / o emulsifier of natural origin can be chosen in particular from at least one non-ethoxylated fatty ester of polyols or at least one naturally biodegradable product having a hydrophilic-lipophilic balance (HLB) of less than 8; the fatty phase preferably representing between 10 and 65% by weight, and preferably of the order of 20 to 55% by
• step b) and adding the mixture obtained in step a) to an aqueous phase with sufficient mechanical stirring to allow dispersion of the fatty phase into fine droplets in the aqueous phase and obtaining an O / W emulsion having a drop size of less than 10 ⁇ m.
• FIG. 1 represents the color pallet used for the evaluation of the whiteness descriptor
• FIG. 2 is a photograph of 6 O / W emulsions obtained from emulsifying compositions according to the invention.
• compositions are produced in the form of an O / W emulsion according to the invention, using the following protocol.
• the compositions of these 6 compositions are reported in Table 1.
• a gelling agent is dispersed in water with stirring with a deflocculating pellet at 1000 rpm.
• the temperature of the water is set at 40 ° C when the gelling agent is xanthan, and at 70 ° C when the gelling agent is hydroxyethylcellulose.
• the beta-cyclodextrin is then wetted in glycerine and the beta-cyclodextrin / glycerine mixture is added to the water / gelling agent mixture with stirring at 1000 rpm in order to obtain an aqueous phase.
• the amount of beta cyclodextrins is set at 2% or 5% by weight of the composition according to the case.
• the 3-polyglyceryl diisostearate is added in sunflower oil or in isopropyl palmitate with magnetic stirring at 40 ° C. to obtain an oily phase.
• the oily phase is then emulsified in the aqueous phase at 40 ° C. with stirring at 1500 rpm for 15 minutes.
• a preservative is added (mixture based on benzyl alcohol and dehydroacetic acid).
• Figure 2 is a photograph of the 6 O / W emulsions obtained according to the formulations given in Table 1.
• compositions For each of these compositions, the viscosity, the size of the drops, the whiteness, the spread, the bold character, and the penetrating character are measured.
• the compositions may be designated indifferently by the terms samples or produced in the following of the present detailed description.
• the viscosity is measured using a Brookfield DV-ll + Pro viscometer.
• a fixed-size mobile (mobile SP2 to SP7 used according to the viscosity levels in accordance with the instructions of the apparatus) is rotated at a speed of 20 rpm in contact with the produced sample.
• the resistance of the product to this rotational movement is recorded for one minute and converted to Pascal. second.
• the viscosity is measured three times and the arithmetic mean of the three values is retained.
• the whiteness descriptor is defined by the color scheme in Figure 1.
• the product is examined under the lamp and compared to the color palette by a panel of evaluators.
• the spreading is evaluated by examining the product after having deposited on the hand 50 to 100 ml of the product, during its spread in 10 rotations, under a lamp. Sprawl is particularly important that there is little resistance to movement between the 5th and the 10th round of the hand.
• the fat character of the compositions is evaluated by examination under the lamp of the product, 1 minute after making 10 rotations of the product on the skin.
• An evaluator panel then evaluates the resistance of the product when the skin on which it has been applied is placed between the thumb and forefinger and a rubbing motion is applied.
• the evaluator panel also takes into account the oily or non-oily appearance of the skin.
• the penetrating character of the product is evaluated by an examination under the lamp of the product two minutes after making 10 rotations of the product on the skin, by sliding over the skin. A panel of evaluators then assesses the amount of product residue recovered.
• the viscosity of the emulsions increases slightly when the concentration of beta-cyclodextrin increases: it goes from 4000 mPas with 2% beta-cyclodextrin to more than 6000 mPas with 5%. Similarly, the viscosity is higher when the thickener used is cellulose instead of xanthan: it goes from 5000 to 8000 mPas.
• the emulsifying compositions according to the invention advantageously make it possible to obtain a very broad range of viscosity, which can make it possible to prepare both milks and viscous creams.
• the size of the drops decreases when the concentration of beta-cyclodextrin increases, it goes from 35 microns with 2% of beta-cyclodextrin to 15 microns with 5%.
• O / W emulsions obtained using the emulsifying compositions according to the invention have excellent sensory properties (grades ranging from 6 to 10 according to the white, spreading, greasy and penetrating criteria).
• the emulsions are less white when the oil used is sunflower oil than when the oil used is isopropyl palmitate: the descriptor is about 8.25 out of 10 in the case of sunflower oil, against 9.25 out of 10 in the case of isopropyl palmitate. However, the whiteness of the sunflower oil remains satisfactory.
• 15 emulsifying compositions according to the invention comprising different percentages of beta cyclodextrin and polyglyceryl-3 diisostearate were used to prepare 15 O / W emulsions according to the conditions given in Example 1 with a fixed amount of 0.7% by weight. of xanthan and a variable amount of sunflower oil. All percentages given are percentages by weight.
• the different formulations made are shown in Table 3 below.
• Viscosity increases significantly as the concentration of beta-cyclodextrin increases from 4000 mPas with 2.5% beta-cyclodextrin to about 6000 mPas with 4.5% beta cyclodextrins. In addition, the viscosity increases significantly when the oil concentration increases, it is 3500 mPas with 17% oil at about 6000 mPas with 35%.
• the concentration of beta-cyclodextrin does not affect the size of the drops when there is 1% of polyglyceryl-3 diisostearate: it remains stable around 25 microns.
• concentration of polyglyceryl-3 diisostearate is increased to 2% by weight, there is a significant decrease in the size of the drops when the concentration of beta-cyclodextrin increases: it goes from about 80 microns with 2 5% beta-cyclodextrin at about 35 microns with 4.5%.
• the emulsion When the concentration of beta-cyclodextrin increases, the emulsion is increasingly white, from 7.5 to 10 with 2.5% beta-cyclodextrin more than 8 out of 10 with 4.5%. In addition, the emulsion is increasingly white when the concentration of sunflower oil decreases from about 8.5 to 10 with 17% by weight of sunflower oil at 7.5 out of 10 with 25% by weight. weight of sunflower oil.
• Plating is significantly better (ie, easier) when the concentration of beta-cyclodextrin decreases and when that of polyglyceryl-3 diisostearate increases. Spreading is also significantly easier when the beta- cyclodextrin concentration decreases and when that of sunflower oil decreases.
• O / W emulsions having a content of polyglyceryl-3 diisostearate greater than or equal to 2% by weight tend to phase out at room temperature.
• O / W emulsions 4, 6 and 15 are particularly stable and have a particularly small drop size after 10 days. These compositions are therefore particularly interesting.
• An emulsifying composition (called emulsifying composition 15) comprising 4.5 parts of beta-cyclodextrin and 1 part of 3-ployglyceryl diisostearate was also used in the form of a premix, that is to say in the form of an emulsifying composition prepared in advance. It makes it possible to obtain, by dispersion at 5.5% in cold water and before addition of sunflower oil, an O / W emulsions having exactly the same characteristics as the emulsion for which the beta-cyclodextrin and the 3-polyglyceryl diisostearate were introduced separately.
• Sorbitol is a particularly interesting alternative and the compositions prepared according to the same procedure but with sorbitol instead of glycerine also showed very satisfactory performance. It is also possible to choose other polyols such as maltitol, mannitol, xylitol or erythritol.
• References 1 to 5 correspond to products entering compositions
• emulsifiers according to the invention and reference T has an ethoxylated and non-biodegradable control product not according to the present invention.
• the characteristics of the emulsions are as follows.
• compositions comprising 4.5 parts of a crystalline betacyclodextrin or 4.5 parts of amorphous beta-cyclodextrin, associated with 1 part of polyglyceryl-3 diisostearate.

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