FACILITATED PREPARATIONS OF VESICLES USING ALKYL POLYPENTOSIDES AND USES OF SAID PREPARATIONS

Abstract

Surfactant system capable of forming a dispersion of vesicles or liposomes consisting of an alkyl polyglycoside of formula RO(X), in which R is a linear or branched alkyl chain, with or without unsaturation, and comprising 8 to 12 carbon atoms, X being the remainder of a pentose, and n representing the average degree of oligomerization is between 1 and 3, and a hydrotrope or co-solvent.

Description

The present invention relates to a method for preparing a dispersion of vesicles or liposomes using at least one alkyl polypentosides. These organized systems can be used in various industries, such as cosmetics, pharmaceuticals, agrochemicals, detergents, water treatment, or soil and aquifer remediation. Organized systems, vesicles, or liposomes are supramolecular aggregates of P1 or several layers of surfactants, forming a more or less spherical capsule ranging in size from micron to submicron (generally 0.1 to 10 µm). These capsules may contain, within the layers, between the layers, and at their core, an aqueous or non-aqueous phase that may contain one or more solubilized or dispersed active ingredients. The entire structure constitutes the encapsulated phase(s). This type of aggregate is also commonly called an onion phase, multilamellar vesicle (MLV) when it consists of a stack of several surfactant layers from the center to the periphery, and a unilamellar vesicle (ULV), or liposome when it consists of only one or a few layers and has a central cavity that serves as a preferred site for encapsulation.There are many methods for the preparation of organized systems, vesicles or liposomes, notably described by RG Laughlin in Colloids Surfaces A: Physicochem. Eng. Aspects 128 (1997). The first method involves applying significant shear to a solution of surfactants or lipids (usually in the form of a lamellar liquid crystal phase). This shear can be imposed by sonication or by forcing the liquid through calibrated orifices, or by membrane filtration or using a high-pressure homogenizer. Another method involves precipitating vesicles by diluting a surfactant solution in a suitable solvent or by dialysis. This method can be coupled with shear to control the particle size distribution and average size of the vesicles. The third procedure involves hydrating a solid film, usually lipid, formed after solvent evaporation.Other methods involve injecting solvents into solutions or depositing droplets of insoluble surfactants onto polar surfaces and immersing them in water. Finally, the most common methods are chemical reactions, such as the precipitation of fatty acids by acidification of the medium or polymerization reactions. WO 93 / 19735 describes a method for preparing capsules of controlled size based on the shear stress imposed by a Couette cell from a concentrated solution of lamellar surfactants. WO 01 / 32146 describes capsules composed of amphiphilic copolymers stabilized by polymerization of the terminal groups, for example, acrylates. A method for preparing liposomes by concentration, drying, rehydration of the solid film, and then filtration is described in US 2004057988A1. EP 023126A1 gives a method for preparing liposomes by the action of rapid cooling, generally under liquid nitrogen, of a lipid dispersion. US 4752425 and US 4737323 give methods for preparing liposomes by injecting a lipid solution dilute in a solvent into an aqueous phase, followed by continuous removal of the solvent. S. Segota, in Advances in Colloid and Interface Science 121 (2006), describes surfactant structures particularly well-suited to forming vesicles and liposomes. The main class of molecules possesses two or more lipophilic chains for a polar head. These are primarily phospholipids and glycolipids, which can be extracted naturally or synthetically. Descriptions of vesicles using double-chain surfactants such as dialkyl-dimethyl-ammonium hydroxides or pairs of oppositely charged surfactants, generally called catanionic, such as mixtures of sodium dodecylbenzene sulfonate (anionic) and didodecyldimethylammonium bromide (cationic). Vesicles have also been observed with single-chain surfactants but generally in complex surfactant / co-surfactant / water mixtures such as mixtures of ethoxylated fatty alcohols (such as 5-ethoxylenic lauryl alcohol or C12E5) with the incorporation of cholesterol as a co-surfactant absolutely necessary for vesicle formation. Alkyl polyglycosides constitute a class of non-ionic surfactants that are particularly appreciated because of the renewable origin of the raw materials that constitute them, their relative gentleness for the skin and mucous membranes, their ease of biodegradation and their low environmental impact. Document DE 19634374A1 describes vesicle dispersions formed with alkyl polyglycosides (APGs) of the formula R0(G)n (1), where R is a linear aliphatic radical having 12 to 22 carbon atoms, and n represents the degree of polymerization of the sugars, or Dp, and is between 1 and 2 (product A). The APG is necessarily mixed with a linear fatty alcohol of 12 to 22 carbon atoms (product B) in a mass ratio A / B of 1 / (0.1 to 2). In other words, the C12 to C22 alcohol represents from 9.1% to 66.7% by weight of the total weight of the A+B system. Preferably, the mixtures also contain lipid co-surfactants, such as sterols like phytosterols or diketylphosphates, which are themselves known to easily form liposomes. D. Balzer, in Nonionic Surfactants, Alkyl Polyglucosides, Surfactant Science series vol. 91, M. Dekker, NY, 2000, studied the crystalline and liquid-crystal structures of PGAs in solution. PGAs with alkyl chains having 8 to 10 carbon atoms form lamellar phases in a mass concentration range of 78% to 81% (C8 / C10 PGAs n=1.5). Longer PGAs, with alkyl chains having 12 to 14 carbon atoms, form lamellar phases at a concentration of at least 65% by mass (C12 / C14 PGAs n=1.3). Considering that the formation of a lamellar phase is a necessary condition for the formation of vesicles or liposomes, APGs of formula (1) ne30 will therefore only be able to form such objects at concentrations at least greater than 65%. Finally, US document 6,251,425 B of 2001 clearly demonstrates that APGs are primary surfactants that cannot form vesicles in the absence of steroids. The complexity of manufacturing and implementing vesicles and liposomes on the one hand, and the difficulty in easily obtaining such organized, stable and dilutable systems with APGs only, constitute technical defects that the present invention seeks to correct. The vesicles or liposomes of the present invention are prepared with at least one alkyl polyglycoside of formula RO(X)n(2), in which R is a linear or branched aliphatic radical, with or without unsaturation, having 8 to 12 carbon atoms. X is a pentose residue such as xylose, arabinose, ribose, or xylulose, in its alpha or beta isomeric form, of the L or D series, and in its furanose or pyranose form. n represents the average degree of oligomerization and is generally between 1 and 3, preferably between 1 and 2. It has been found, and this forms the basis of the present invention, that alkyl polyglycosides of formula (2) can readily form a dispersion of stable and dilutable organized systems, vesicles, or liposomes, even with linear alkyl chain lengths of 12 carbon atoms or less. The term "readily" refers to obtaining organized systems, vesicles, or liposomes, meaning the absence of co-surfactants, particularly steroids that alone form such systems or fatty alcohols, and the surprising ease of implementation without the use of special mixers, such as sonication apparatus or duvet-type mixers, and without the need for a solid phase obtained by precipitation or freezing, or for solvent injection or evaporation."Stable" means the persistence and maintenance of the average size of the vesicles or liposomes formed according to the method of the invention as a function of the storage time and storage temperature, generally between 4°C and 60°C. "Dilutable" means the possibility of dispersing a concentrated solution of vesicles or liposomes in a suitable solvent, generally aqueous, by a dilution factor of 2 to 1000 times, and preferably 5 to 100 times, while ensuring the persistence and size of the initial objects. One of the features of the invention is the surprising stability of the organized systems, vesicles or liposomes formed, even in complex formulations, such as emulsions, washing or detergent preparations, plant protection formulations or preparations for soil remediation. The invention therefore relates to a method for preparing a dispersion of multilamellar vesicles or liposomes comprising the dispersion of a surfactant system capable of forming vesicles or liposomes in an aqueous phase, a solvent or an oil, characterized in that this surfactant system contains at least one alkyl polyglycoside of formula RO(X)n, in which R is a linear or branched alkyl chain, with or without unsaturation, and comprising 8 to 12 carbon atoms, X is the remainder of a pentose, preferably xylose, and n represents the average degree of oligomerization and is between 1 and 3. The invention also relates to a method for incorporating one or more active ingredients—cosmetic, pharmaceutical, phytopharmaceutical, perfume, enzyme, nutrient, trace element, biological material, essential oil, or agents capable of oxidizing or degrading organic molecules—into multilamellar vesicles or liposomes. This method consists of mixing said active ingredients, crude or diluted in an oil, solvent, or water, with a surfactant system and then dispersing this mixture in an aqueous phase, solvent, or oil. The method is characterized in that this surfactant system contains at least one alkyl polyglycoside of formula RO(X)n, in which R is a linear or branched alkyl chain, with or without unsaturation, comprising 8 to 12 carbon atoms, X is the remainder of a pentose, preferably xylose, and n represents the average degree of oligomerization and is between 8 and 12. between 1 and 3. The term "dispersion" includes indiscriminately dissolution, solubilization, the formation of a suspension or a colloidal solution in a continuous aqueous or non-aqueous phase. The surfactant system according to the invention may consist of: - 5% to 99% of an alkyl polyglycoside of formula RO(X)n, in which R is a linear or branched alkyl chain, with or without unsaturation, and comprising 8 to 12 carbon atoms, X being the remainder of a pentose, preferably xylose, and n representing the average degree of oligomerization is between 1 and 3, preferably between 1 and 1.5; - 0.1% to 70% of one or more co-surfactants having an HLB of at least 10; - from 0% to 70% of a hydrotrope or co-solvent chosen from linear or branched alcohols from Cl to C20, the .glycol ethers, amyl, butyl, hexyl, 2-ethylhexyl, octyl, isononyl, isodecyl, octyldecyl glycosides, glycerol and partial glycerol derivatives, terpineols, esters of organic acids such as acetic, formic, lactic, succinic, tartaric, glutaric, glutamic, adipic, lauric, oleic acid; and - from 0.1% to 70% water. To ensure better stability and dispersion of the vesicles or liposomes, a surfactant system comprising one or more alkyl polyglycosides of formula (2) and one or more co-surfactants and / or one or more co-solvents can be advantageously used. The co-surfactant(s) do not necessarily themselves form organized systems or liposomes. The mass ratio of alkyl polyglycoside to co-surfactant and / or co-solvent will then be between 0.5 and 1000, preferably from 1 to 100. In other words, preferably the co-surfactant or co-solvent will represent 1% to 50% by weight relative to the total weight. Preferably, to obtain a stable and dilutable dispersion in aqueous medium, a co-surfactant with an HLB greater than 10, and preferably even greater than 15, should be used. HLB refers to the Hydrophilic-Lipophilic Balance, notably described in "Surface Agents and Emulsions" in the Galenica collection published by "Technique et Documentation (Lavoisier)" in 1983, and can be obtained by calculation according to the Griffin method (Griffin WC: "Calculation of HLB Values ​​of Non-Ionic Surfactants," Journal of the Society of Cosmetic Chemists 5 (1954): 259) or by the Davies method (Davies JT: "A quantitative kinetic theory of emulsion type, I. Physical chemistry of the emulsifying agent," Gas / Liquid and Liquid / Liquid Interface. Proceedings of the International Congress of Surface Activity (1957): 426-438). Examples of co-surfactants used include, but are not limited to, octyl, hexyl, 2-ethylhexyl, butyl, 2-methylbutyl or 3-methylbutyl polyglycosides, polyethoxylated sorbitan esters such as ethoxylated sorbitan esters of lauric, oleic, stearic, tri-oleic acid, polyethoxylated oils such as hydrogenated castor oil with 40 moles of ethylene oxide, and highly ethoxylated fatty alcohols such as lauric alcohol with 23 ethoxylated units and oleic alcohol with 28 ethoxylated units.As co-solvents, linear alcohols such as ethanol, butanol, pentanol, hexanol, octanol, decanol, dodecanol, or branched alcohols such as 2-ethylhexanol, isoamyl alcohol, 3-methylbutanol, 2-butyloctanol, 2-butyldecanol, 2-hexyloctanol, 2-hexyldecanol, 2-octyldecanol, 2-hexyldodecanol, 2-octyldodecanol, 2-decyltetradecanol, terpineols, as well as glycerol or its derivatives including monoglycerol esters, polyglycerols and their derivatives such as polyglycerol monostearate or polyglycerol polyricinoleate, may also be used. butylene glycol, propylene glycol, glycol ethers such as diethylene glycol butyl ether, diethylene glycol propyl ether, triethylene glycol ethyl ether, triethylene glycol methyl ether, triethylene glycol butyl ether and their acetates, fatty acid esters such as methyl, butyl, i.so-butyl, amyl, propyl, iso-propyl, 2-ethylhexyl, hexyl, octyl, decyl, isodecyl of C12 to C24 fatty acids saturated or having one or more unsaturations. Preferably, to obtain a stable and dilutable dispersion in non-aqueous medium, an HLB co-surfactant of less than 10 or preferably less than 7, preferably even less than 5, will be advantageously used instead of an HLB co-surfactant of at least 10.By way of example and without being limited to them, we can choose as low HLB co-surfactants, sorbitan esters such as sorbitan monolaurate, monooleate, monostearate, trioleate, sorbitan tristearate, weakly ethoxylated sorbitan esters such as POE(2) sorbitan stearate, propylene glycol esters of fatty acids such as propylene glycol monooleate, propylene glycol monomyristate, glycerol monoesters such as glycerol monooleate, glycerol monostearate, saccharoesters such as sucrose myristate, palmitate or stearate, sucrose di, tri and polystearate, sucrose di, tri and polypalmitate, sucrose di, tri and polylaurate, alcohols weakly ethoxylated fats such as cetyl alcohol POE(2), oleic alcohol POE(2), weakly ethoxylated oils such as 5-mol hydrogenated castor oil of ethylene oxide. The invention has applications in many fields. It relates to vesicles or liposomes which contain from 1% to 99% by weight relative to the total weight of the vesicles or liposomes, preferably from 10% to 95% and even more preferably from 30% to 90%, of one or more active cosmetic, pharmaceutical, phytopharmaceutical, perfume, enzyme, nutrient, trace element, biological material, essential oil, or agents capable of oxidizing or degrading organic molecules, crude or diluted indifferently in oil, solvent or water.The invention also relates to an oil-in-water emulsion, aqueous or hydro-alcoholic solution, aqueous or hydro-alcoholic gel containing from 0.01% to 90% by weight, preferably from 0.1% to 50% and even more preferably from 1% to 20% by weight of vesicles or liposomes and prepared using at least one surfactant system according to the invention, as well as a water-in-oil emulsion, solvents or mixtures of solvents, microemulsion, containing from 0.01% to 90% by weight, preferably from 0.1% to 50% by weight and even more preferably from 1% to 10% by weight of vesicles or liposomes and prepared using at least one surfactant system according to the invention. Cosmetics and (Dermo)pharmaceuticals: The invention will be used in the fields of cosmetics, dermopharmacy, and pharmaceuticals to encapsulate active ingredients, releasing them over time or in response to external factors such as temperature increases, shear stress, or chemical reactions like pH changes, hydrolysis, oxidation, or enzymatic reactions. It can also be used to encapsulate sensitive materials, particularly those susceptible to oxidation or UV exposure, to protect them and maintain their efficacy. Furthermore, it can be used to deliver vesicles to targeted sites of action through the dermis, epidermis, or hypodermis, or to absorb them, particularly through the skin or hair, to prolong the desired effect.One of the distinctive features of the invention is the production of stable vesicles even in complex environments, particularly in emulsions and concentrated surfactant solutions. Vesicles prepared by the methods of the invention will therefore be particularly useful in aqueous preparations in the form of solutions, dispersions, gels, lotions, and in oil-in-water (O / W), water-in-oil (W / O), or complex systems such as multiple emulsions (W / O / W or W / O / O), especially in preparations such as creams, milks, ointments, salves, gels, and lotions. Since the vesicles prepared according to the methods of this application can be dispersed in both aqueous and non-aqueous media, they can also find applications in fields containing little or no water. Examples include massage oil formulations, sunscreen oils, sports oils, and skin treatment oils. The invention will also find applications in solid or paste-like preparations such as makeup, including lipsticks, mascaras, and foundations. The encapsulated materials may include, for example, vitamins such as vitamins A, E, or C; synthetic or natural fragrances such as benzyl acetate, linalyl acetate, linalyl benzoate, citral, citronellal, lilial, eugenol, citronellol, linalool, terpene derivatives, and essences of sage, chamomile, carnation, vetiver, and lavandin.essential oils such as lavender, thyme, savory, sage, mint, cumin, caraway, anise, fennel, dill, eucalyptus, cajeput, niaouli, clove, pine, cedar, cypress, juniper, lemon, orange, bergamot, cinnamon, bay leaf, chamomile; anti-inflammatories such as plant extracts, alpha-bisabolol, panthenol, alpha-tocopherol; anti-burn agents such as allantoin; anti-aging agents such as retinol; self-tanning agents such as dihydroxyacetone (DHA); depigmenting agents such as kojic acid, coumaric acid, arbutin; slimming agents such as caffeine; antiperspirants such as aluminum, zinc, or zirconium salts, diethylenetriamine pentaacetic acid; and other agents. anti-dandruff agents such as zinc or aluminum pyrithione, salicylic acid, pyridone salts and piperazine derivatives, UV filters such as benzophenone derivatives, cinnamic acid esters,salicylic acid esters, 3-benzylidene camphor, antioxidants such as ascorbic acid and its derivatives, citric acid and its derivatives, glutamic acid, glutamates and their derivatives, lactic acid and its derivatives, tartaric acid and its derivatives, bioflavonoids, butylhydroxyhydroxyanisole, carotene and its derivatives, sulfites such as sodium bisulfite, chlorobutanol, preservatives such as parabens, phenoxyethanol, 2-bromo-2-nitropropane-1,3-diol, formaldehyde, pantanediol, sorbic acid, moisturizing agents such as glycerol, sorbitol, collagen, pro-collagen, gelatin, aloe vera, hyaluronic acid, urea, insect repellents such as acetamipiride, etofenprox, permethrin, cypermethrin, N,N-diethyl-m-toluamide, butylacetylaminopropionate, pharmaceutical actives, such as disinfectants like chlorhexidine gluconate, benzalkonium chloride,Benzoic acid, cetylpyridinium chloride, anti-inflammatories such as arnica tincture, eucalyptol, menthol, dimethoxy-1,2-benzene, anti-acne agents such as tretinoin derivatives, azelaic acid, salicylic acid, antifungals such as pyridone derivatives like cyclopiroxolamine, imidazole derivatives such as clotrimazole, folic acid, riboflavin, sequestrants such as mucinic acid, phytic acid, NTA, EDTA, colorants, pH adjusters, natural or synthetic flavorings. Detergents: Organized systems, vesicles, or liposomes prepared according to the methods of the present invention will be used in detergent formulations, particularly in laundry detergents, fabric softeners, hard surface cleaners, dishwashing liquids, or vehicle cleaning products. In the field of laundry detergents, especially liquid detergents or gels, the encapsulated materials may be, for example, perfumes, notably to prolong the "fresh" effect and pleasant scent of clean laundry, or to protect it from enzymes present in the formulation, particularly lipases, which can denature the laundry during the wash cycle. Enzymes may also be encapsulated to protect them from UV radiation, thermal or chemical degradation, particularly due to alkaline pH. The vesicles may therefore also contain UV-absorbing agents, bleaching agents, or optical brighteners.as well as whitening activators, non-ionic or cationic vitamins, antimicrobial, antifungal or antiviral agents, antiperspirants, deodorants, nutrients, skin protectants and skin moisturizers. As examples of perfumes and odorants, we can mention, for example and without limiting ourselves, synthetic or natural perfumes such as benzyl acetate, linalyl acetate, linalyl benzoate, citral, citronellal, lilial, eugenol, citronellol, linalool, terpene derivatives, essences of sage, chamomile, carnation, vetiver, lavandin, essential oils such as essential oils of lavender, thyme, savory, sage, mint, cumin, caraway, green anise, fennel, dill, eucalyptus, cajeput, niaouli, clove, pine, cedar, cypress, juniper, lemon, orange, bergamot, cinnamon, bay leaf, chamomile.Examples of bleaching agents include hydrogen peroxide, sodium hypochlorite, potassium percarbonates, sodium perborates, and peracids. Examples of bleaching activators include N,N,N',N'-tetraacetylethylenediamine or its derivatives, sodium nonanoyloxybenzene sulfonate and its derivatives, and sodium 4-benzoyloxybenzene sulfonate. Enzymes enhance the cleaning action of these preparations, particularly on greasy and food stains. Examples include amylases, cellulases, lipases, peroxidases, and proteases, some of which are marketed by Novosyme. Plant Protection Formulations The invention also finds applications in the field of agrochemistry, particularly for the formulation of herbicides, insecticides, fungicides, algaecides, rodenticides, molluscicides, acaricides, growth regulators, nutrients, trace elements, fertilizers, elicitors, repellents against insects, mammals or birds, and baits for insects or rodents. Plant protection formulations can be in the form of aqueous or non-aqueous solutions, oil-in-water (O / W) or water-in-oil (W / O) emulsions, microemulsions, superemulsions, gels, emulsifiable concentrates, granules, wettable powders, and fragmentable or dispersible tablets or sticks. The objective of encapsulating a material in vesicles of the invention is to allow precise dosing and controlled release of active ingredients, to reduce the toxicity of pesticides or to protect biologically active materials in particular from external constraints such as UV radiation, chemical reactions such as those induced by changes in pH or complexation with ions in particular calcium or magnesium present in hard water. Examples of pesticides that can be encapsulated by the vesicles of the invention include, but are not limited to, amide-type herbicides such as benzipram, cyprazole, formesafen, anilides such as metamifop, pentanochlor, arylalanines, chloroacetanilides such as alchlor, metazochlor, propachlor, terbuchlor, sulfonanilides such as benzofluor, pyrimisulfan, benzoic acids such as dicamba, 2,3,6-TBA, tricamba, phthalic acids, picolinic acids, quinoline carboxylic acids, benzoylcyclohexanediones, benzofuranyl alkylsulfonates, carbamates, and carbanilates such as chlorobufam, chloropropham, desmedipham, and phenmedipham. phenmedipham-ethyl, cyclohexene oximes such as cloproxydim, cycloxydim, profoxydim, cycloproxylisoxazoles, dicarboximidines such as benzfendizone, flumixazin, dinitroanilines, dinitrophenols,diphenyl ethers such as ethoxyfen, dithiocarbamates, halogenated aliphatic herbicides, imidazolinones, nitriles such as bromoxynil, chloroxynil, dichlobenil, organophosphate herbicides such as 2,4-DEP, fosamine, glufosinate, glyphosate, oxadiazolones, phenoxy herbicides such as 2,4-DEB, etnipromid, 2,4-D, MCPA, 2,4-DB, dichloprop, mecoprop, diclofop, fenaxoprop, fluazifop, clodinafop, haloxifiop, phenylenediamines, pyrazoles such as metazochlor, benzofenap, pyridazines, pyridazinones, pyridines such as aminopyralid, pyrimidinediamines, thiocarbamates such as sulfallate, thiobencarb, thiocarbonates, triazines such as trihydroxytriazine, atrazine, cyprazine, atraton, prometon, aziprotryne, triazinones, triazoles, triazolones such as bencarbazone, propoxycarbazone, triazolopyrimidines,Urea-based herbicides such as phenylureas, sulfonylureas such as amidosulfuron, ethoxysulfuron, mezosulfuron, chlorsulfuron, metsulfuron, triasulfuron, thiadiazolylureas such as buthiron, thiazafluron as well as quaternary ammonium compounds and their derivatives, inorganic herbicides such as copper sulfate, ammonium sulfamate, sodium chlorate, de-potassium cyanate. Examples of insecticides that can be encapsulated include those derived from plants such as dlimonene, nicotine, pyrethrins, jasmolins, pyrethroids, carbamate insecticides such as aryl-methylcarbamates, mono-methyl or dimethyl heterocyclic carbamates such as carbofuran, carbosulfan, primicarb, carbamate oximes such as oxamyl, thiofanox, methomyl, organochlorine insecticides such as DDT, methoxychlor, hexachlorocyclohexane (HCH) and its derivatives, heptachlor, mirex,organophosphate insecticides such as orthophosphates (chlorfenvinphos, dichlorvos), phosphorothionates (bromphos, diazinon, parathion), phosphorothionates, phosphorothiolothioneates (dimethoate, disulfoton, menazon), phosphonates (triclorphon, butonate), pyrophophoramides (shradan), insect growth blocking insecticides such as chitin inhibitors such as novaluron, penfluron, natural or synthetic juvenile hormones such as methoprene, kinoprene, formamidine insecticides such as chlorodimeform, amitraz, benzoylphenylurea derivative insecticides such as diflubenzuron, penfluron, inorganic insecticides such as borax, copper oleate, sodium thiocyanate. Examples of fungicides that can be encapsulated according to the invention include copper-based fungicides, such as Bordeaux mixture, copper oxychloride, copper oxides, and copper hydroxides.mercury-based fungicides such as organomercury compounds like PMA, methoxyethylmercury acetate, thiomersal, dithiocarbamates like thiram, maneb, phthalimides like captan, phthalonitriles like chlorothalonil, dicarboximides like vinclozolin, dinitrophenols like dinocap, dinocton, benzimidazoles like benomyl, cypendazole, oxathiines like carboxin, morpholines like tridemorph, carbamorph, hydroxyaminopyrimidines like ethirimol, antibiotic fungicides such as kazugamycin, strobilurines and their derivatives, phenylamides like metalaxyl, organophosphate compounds like pyrazophos, fosetyl, imidazoles like cyazofamid, Irpodione, prochloraz, triazoles such as hexaconazole and epixiconazole, guanidine derivatives, chlorinated aromatics such as quintozene, dichloran, chlorothalonil, and dicloran. Application for water treatment and soil and aquifer remediation. The invention also finds applications in the field of soil and aquifer remediation and water treatment, particularly in septic tanks. It is already known that incorporating an oxygenating agent increases the performance of bioremediation operations for polluted soils, especially those contaminated by hydrocarbons. The objective is to increase the number of bacteria capable of biodegrading the pollutants present by injecting formulations that, generally through chemical reactions, supply oxygen to the environment. This type of preparation is described in particular in US patent 5,264,018.In the case of aquifer and groundwater pollution, particularly by chlorinated pollutants, it can be advantageous to incorporate chemical agents that initiate oxidation reactions, either to completely and directly degrade the pollutant or to make it more readily accessible to microorganisms for complete biodegradation. Examples of such compounds include Fenton reagents, like those described in US patent 6,268,205. However, in all cases, the reagents can be relatively unstable, degrade rapidly, and lose much of their effectiveness before reaching their target site. Therefore, it is beneficial to encapsulate reagents that release oxygen and / or hydrogen and / or oxidize pollutants in vesicles prepared according to the invention.This is to ensure their transport to the area to be treated, to allow controlled release to maintain long-term effectiveness, or to reduce the toxicity of said materials to the surrounding environment. By way of example, and without limitation, materials that can be encapsulated by a vesicle dispersion of the invention include hydrogen peroxide, urea / hydrogen peroxide complexes, sodium percarbonate, calcium peroxide, magnesium peroxide, potassium permanganates, sodium persulfate, and sodium bisulfite. Catalysts, trace element-rich nutrients, enzymes, bacteria, pH adjusters, and complexing agents can also be encapsulated to enhance the oxygenation, bioremediation, or oxidation of the treated environment. Preparation: Preferably, the materials to be encapsulated are liquid or solubilized in a liquid. They can therefore be diluted in water, a solvent, or an oil to the concentration allowing their complete solubilization. The active materials and, if necessary, their solvent thus constitute the phase to be encapsulated. The phase to be encapsulated represents from 1% to 99% by weight relative to the total weight of the vesicles or liposomes, preferably from 10% to 95%, and even more preferably from 30% to 90%. The vesicles or liposomes shall be prepared by thoroughly mixing the phase to be encapsulated with the surfactant system according to the invention at room temperature or at a temperature above, but preferably below, 100°C.Preferably, low-shear mixers are preferred, such as pendulum agitators with one or more propellers or an anchor, and double-rotation agitators with central agitation using one or more propellers and peripheral agitation with one or more scraper blades conforming to the shape of the reactor. Kneaders and mixers can also be used. High-shear agitators, such as rotor-stator mixers, high-speed toothed propellers, horizontal agitators with a shaft and blades rotated by a motor, and colloid mills, are best avoided. The stirring time may vary from a few minutes to several hours until a viscous liquid is obtained, generally having a viscosity measured using a Brookfield type viscometer of 100 to 500,000 centipoise at the temperature of the mixture or a homogeneous paste (especially at 25°C).This concentrated preparation of vesicles or liposomes can be used immediately for the preparation of pharmaceutical, cosmetic, and detergent products, for water or aquifer treatment, or stored at a suitable temperature, generally 4 to 45°C or higher, but preferably below 100°C. To increase the stability of the concentrate, the addition of agents that block or slow bacterial or fungal growth may be necessary. In this case, they will be added during the mixing phase at concentrations that guarantee their effectiveness. In cosmetic preparations consisting of an aqueous continuum, whether in the form of a solution, gel, or oil-in-water emulsion, the percentage of vesicles or liposomes will vary from 0.01% to 50% of the total weight of the preparation, preferably from 0.1% to 20%.In the case of reverse preparations, particularly water-in-oil emulsions, the incorporation rate will generally be from 0.01% to 30% by weight and preferably from 0.1% to 10%. In detergent preparations, particularly those intended to encapsulate one or more enzymes in liquid detergents or gels, the vesicles or liposomes may contain from 2% to 15% of enzymes by weight and will be incorporated at a rate of 0.1% to 15% by weight relative to the total weight of the preparation. For the encapsulation of perfumes or essential oils, in order to prolong the freshness of laundry for example, the rate of incorporation of vesicles or liposomes in the preparations will vary for example from 0.1% to 20% relative to the total weight of the preparation. In the case of plant protection products, the concentration of active ingredients in vesicles or liposomes and the incorporation rate in the preparations will depend on the nature of said active ingredients and the regulatory requirements of the country authorizing their use. The incorporation rate can vary, for example, from 0.01% to 10% by weight of the preparation for highly effective active molecules such as those in the sulfonyl-urea family like metsulfuron methyl, or from 10% to 90% by weight of the preparation for less active herbicides such as 2,4-D, dimethylamine salt. For the treatment of wastewater and septic tanks, the application of a preparation containing 0.1% to 90% by weight of vesicles or liposomes, preferably 1% to 50%, and even more preferably 5% to 30%, will be carried out intermittently. For the treatment of aquifers and groundwater, treatments with a preparation containing 0.01% to 50% by weight of vesicles or liposomes, preferably 0.1% to 10%, may be applied intermittently or continuously for the duration of the remediation operation. Method for characterizing vesicles and liposomes. The characterization technique used consists of observing cryofracture replicas of surfactant solutions using transmission electron microscopy. This method is widely documented, notably by A. GULIK, LP AGGERBECK, J. CDEDIEU and T. GULIK-KRZYWICKI, in Journal of Microscopy, Vol. 125, Pt 2, February 1982, pp. 207-213, or more recently by O. MONDAIN-MONVAL in Current Opinion in Colloid and Interface Science, 10 (2005), 250-255. The method used was cryo-etching, which allows for the creation of a replica of the structure observable by transmission electron microscopy. This technique comprises four essential steps: 1. freezing; 2. fracturing and etching; 3. shading and formation of the replica; 4. cleaning of the replica. Finally, the replica was visualized using a transmission electron microscope and the images were visually analyzed. To be consistent with the invention, the photographs must demonstrate a homogeneous dispersion of spherical or quasi-spherical objects in both positive and negative planes, and, in the case of multilamellar vesicles, exhibit several spherical striations at the periphery, reflecting the coiling of several layers. Furthermore, the photographs must not exhibit broad cleavage zones, represented by linear streaks, indicating the presence of an uncoiled lamellar phase resulting from a system incapable of spontaneously forming vesicles or liposomes. The invention will be illustrated in more detail by the following examples, given solely for illustrative purposes, in which the characteristics of the products obtained are evaluated according to the criteria described above. Example 1: Visualization of Multilamellar Vesicles According to the Invention. 5.25 g of octyl / decyl polyxylosides (XYLC8 / 10 DP=1.13) are mixed with 44.75 g of water / glycerin using a mechanical stirrer at 500 rpm for 30 minutes at 80°C, then cooled to room temperature while maintaining stirring. A cryofracture replica is then made on this preparation and visualized by transmission electron microscopy (TEM). The resulting image (Image 1) clearly shows the presence of numerous vesicles ranging from 0.2 to 1 µm. Numerous circular grooves are visible, thus indicating the formation of multilamellar vesicles. Example 2 Demonstration of the robustness of multilamellar vesicles according to the invention A decyl poly-xyloside (Xyl C10) is dispersed in a water / glycerin solution at different concentrations using a mechanical stirrer at 500 rpm for 30 minutes at 80 [deg.]C, then cooled to room temperature while maintaining stirring. Each dispersion is sampled to obtain a cryofracture replica, which is then visualized by TEM. The persistence of multilamellar vesicles is verified by the presence of characteristic objects. The results obtained are shown in the following table and in images 2 to 5. Dilution factor 1 2 8 16 % XYLC10 15 7.5 1.875 0.9375 DP=1.5 Observation Dispersions Dispersions Uni- Structures Uni- Structures homogeneous lamellar in lamellar in of vesicles of vesicles mixture with mixture with multilamellar multilamellar a few a few multilamellar multilamellar N[deg.] Images 2 3 4 5 Example Comparative 1 Decyl polyxylosides (XylC10 DP=1.25) and decyl polyglucosides (GluC10 DP=1.3) are dispersed at 15 wt% in a water / glycerol mixture according to the protocol of Example 1. The proportion of GLUC10 DP=1.3 in the surfactant mixture is denoted R. This proportion varies from R=1 for a solution containing only GluC10 DP=1.3 to R=0 for a solution containing only XYLC10 DP=1.25. A cryofracture replica is obtained for each dispersion and then observed by TEM. The observation of multilamellar vesicles is denoted 20 MLV, that of a non-coiled lamellar phase is denoted L, and the observation of a micellar phase is denoted MC.R 1 0, 9 0, 8 0, 7 0, 6 0, 5 0, 4 0, 3 0, 2 0, 1 0 Observations MC MC MC MC MC MC MC MC L MLV MLV MLV at TEM This example shows that a minimum of 70% by mass 25 of alkyl pentosides (xylC10 DP=1.25) will be required in the surfactant mixture5 to obtain a lamellar phase at the test dilution and a minimum of 80% by mass to obtain a homogeneous dispersion of multilamellar vesicles. Decyl polyglucoside and mixtures containing 40% to 90% of this polyglucoside do not form vesicles, thus demonstrating the specificity of alkyl poly-xylosides to form such objects. Example 3 Aqueous dispersion of vesicles stable at low temperature according to the invention. Mixtures of decyl polyxyloside (Xyl C10 DP=1.5) and co-surfactants of various HLBs are dispersed at 7.5 wt% in a water / glycerol mixture according to the protocol described in Example 1. The surfactant-to-co-surfactant ratio is 10. For each of the co-surfactants used, the resulting dispersions are stored at 5°C for 3 months and then observed visually and under an optical microscope (10x magnification). Cryofracture replicas are performed and observed by TEM on all samples before the stability study at 5°C and then on the stable samples after 90 days at 5°C. The following table reports the results obtained according to the HLB (Hydrophilic / Lipophilic Balance) of the co-surfactant. HLB of the co-surfactant (t=0) (t=90d at 5°C) 4.7 Yes - 10.6 Yes - 14.2 Yes Yes 16.7 Yes Yes The presence of co-surfactants with high HLB (>14) gives good stability and homogeneous dispersion of multilamellar vesicles even after 3 months at 5°C. The use of co-surfactants with low HLB (<11) shows an alteration of multilamellar vesicles under these storage conditions. Example 4 Oily dispersion of vesicles according to the invention. A first dispersion is carried out by mixing, using a mechanical stirrer at 500 rpm and 50°C, 45 g of octyl / decyl polyxyloside (XYL C8 / C10 DP=1.3) with 24 g of sorbitan oleate (Radia 7125 from OLEON, HLB=4.7) and 31 g of water. After stopping the heating, the mixture thus obtained is left under mechanical stirring until it reaches room temperature. 45 g of this mixture is then dispersed in 55 g of paraffin oil (Marcol 82) under mechanical stirring and at room temperature. This gives a homogeneous dispersion of liquid crystal phase in the oil and observation under an optical microscope of a sample placed between two crossed polarizers 25 shows the presence of objects characteristic of vesicles.

Claims

CLAIMS 1. A method for preparing a dispersion of multilamellar vesicles or liposomes comprising the dispersion of a surfactant system capable of forming vesicles or liposomes in an aqueous phase, a solvent or an oil, characterized in that this surfactant system contains at least one alkyl polyglycoside of formula RO(X)n in which R is a linear or branched alkyl chain, with or without unsaturations, and comprising 8 to 12 carbon atoms, X is the remainder of a pentose, preferably xylose, and n represents the average degree of oligomerization and is between 1 and 3.

2. A process for including one or more active cosmetic, pharmaceutical, phytopharmaceutical, perfume, enzyme, nutrient, trace element, biological material, essential oil, or agent capable of oxidizing or degrading organic molecules in multilamellar vesicles or liposomes, consisting of mixing said active crude or diluted materials in an oil, solvent, or water with a surfactant system, and then dispersing this mixture in an aqueous phase, solvent, or oil, characterized in that this surfactant system contains at least one alkyl polyglycoside of formula RO(X)n in which R is a linear or branched alkyl chain, with or without unsaturation, comprising 8 to 12 carbon atoms, X is the remainder of a pentose, preferably xylose, and n represents the average degree of oligomerization and is between 1 and 3.

3. Surfactant system characterized in that it comprises: from 5% to 99% of alkyl polyglycoside of formula RO(X)n, in which R is a linear or branched alkyl chain, with or without unsaturation, and comprising 8 to 12 carbon atoms, X being the remainder of a pentose, preferably xylose, and n representing the average degree of oligomerization is between 1 and 3, preferably between 1 and 1.5; from 0.1% to 70% of one or more co-surfactants having an HLB of at least 10; from 0% to 70% of a hydrotrope or co-solvent selected from linear or branched alcohols of Cl to C20, glycol ethers, amyl, butyl, hexyl, 2-ethylhexyl, octyl, isononyl, isodecyl, octyldecyl glycosides, glycerol and partial glycerol derivatives, terpineols, esters of organic acids such as acetic, formic, lactic, succinic, tartaric, glutaric, glutamic, adipic, lauric, oleic acid; and from 0.1% to 70% water.

4. Surfactant system characterized in that it comprises: - from 5% to 99% of an alkyl polyglycoside of formula RO(X)n, in which R is a linear or branched alkyl chain with or without unsaturation, and comprising 8 to 12 carbon atoms, X being the remainder of a pentose, preferably xylose, and n representing the average degree of oligomerization is between 1 and 3, preferably between 1 and 1.5; - from 0.1% to 70% of one or more co-surfactants having an HLB less than 10; - from 0 to 70% of a hydrotrope or co-solvent selected from linear or branched alcohols from C1 to C20, glycol ethers, amyl, butyl, hexyl, 2-ethylhexyl, octyl, isononyl glycosides, of isodecyl, octyldecyl, glycerol and partial glycerol derivatives, terpineols, esters of organic acids such as acetic, formic, lactic, succinic, tartaric, glutamic, adipic, tauric, oleic acid; and 0.1% to 70% water. 5.System according to claim 3 or 4, characterized in that it is in the form of vesicles or liposomes which contain from 1% to 99% by weight relative to the total weight of the vesicles or liposomes, preferably from 10% to 95% and even more preferably from 30% to 90%, of one or more active cosmetic, pharmaceutical, phytopharmaceutical, perfume, enzyme, nutrient, trace element, biological material, essential oil, or agents capable of oxidizing or degrading organic molecules, crude or diluted in oil, solvent or water.

6. System according to claim 5, characterized in that it is in the form of an oil-in-water emulsion, aqueous or hydro-alcoholic solution, aqueous or hydro-alcoholic gel which contains from 0.01% to 90% by weight, preferably from 0.1% to 50% and preferably still from 1% to 20% by weight of vesicles or liposomes. 7.A system according to claim 5, characterized in that it is in the form of a water-in-oil, solvent, or solvent mixture emulsion, or a microemulsion, containing from 0.01% to 90% by weight, preferably from 0.1% to 50% by weight, and more preferably from 1% to 10% by weight of vesicles or liposomes.

8. Use of a dispersion of vesicles or liposomes according to any one of claims 6 or 7 for the formulation of cosmetic, pharmaceutical, phytopharmaceutical, or detergent products, for water treatment, or for soil remediation.

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