Process for preparing microcapsules of lipophilic active ingredients in inorganic and inorganic hybrid materials

Abstract

Process for preparing microcapsules of lipophilic actives in inorganic and inorganic hybrid materials. The invention relates to a process for synthesizing silica microcapsules comprising an oily phase comprising at least one lipophilic active comprising the following steps: a) preparation of silica nuclei by hydrolysis of at least one silica precursor in water in an acidic catalytic medium, a') addition at the end of step a) or during step a) of an oily phase in an oily phase / silica precursor ratio greater than or equal to 1 / 1, b) formation of a matrix phase by mixing at least one condensation agent selected from at least one branched or linear basic polycationic polymer, and at least one monovalent, divalent or trivalent anion, c) condensation in a basic medium of the silica nuclei obtained in step a) and of the oily phase by mixing under stirring with the matrix phase obtained in step b) at an alkaline pH less than or equal to 10.

Description

Title of the invention: Method for preparing microcapsules of lipophilic active ingredients in inorganic and inorganic hybrid materials technical field

[0001] The present invention relates to the field of synthesis by soft chemistry and more particularly to the preparation of microcapsules of lipophilic active ingredients surrounded by inorganic materials and / or hybrid inorganic materials. The microcapsules formed are intended to be used as an active ingredient delivery system. Areas of application include cosmetics, perfumery, laundry / household care, hygiene and health products, biocides, biostimulants, plant protection products, food products, and repellents for human or veterinary use. PRIOR TECHNIQUE

[0002] Microencapsulation is a technology that allows the immobilization of an active ingredient in a microcapsule with a size ranging from Ipm to 1000 pm. The active ingredient is finely dispersed in a continuous matrix (sphere) or coated with a layer of material (capsule or core / shell).

[0003] Microencapsulation is used to stabilize an active ingredient, protect it from chemical or physical phenomena such as oxidation, humidity, heat, and UV radiation, and control its release over time or under various external stimuli (heat, friction, pH). Microencapsulation can provide significant added value and new functionalities to encapsulated ingredients and thus finds numerous industrial applications, particularly in the pharmaceutical (human and veterinary), food, cosmetic (human and veterinary), plant protection, perfume, and flavor industries.

[0004] Many microencapsulation processes are available and based on mechanical, chemical or physico-chemical methods such as atomization (spray-drying, spray-coating), extrusion, fluidized bed, supercritical fluids, alginate microgels, coacervation, interfacial polymerization and sol-gel chemistry.

[0005] The many advantages of microencapsulation in silica or hybrid capsules have been described in particular in US document 10,099,194 B2 which concerns silica sol-gel microcapsules.

[0006] These silica sol-gel microcapsules are generally obtained by hydrolysis and condensation of a silica precursor in the presence of an organic solvent in an alkaline medium such as concentrated ammonia or in a strong acidic medium, solvents hydrophobic or petroleum-based surfactants. A process for synthesizing silica capsules from an emulsion obtained with surfactants and a conventional sol-gel condensation requiring an increase in pH with a strong base is known from US document 2012 / 104639.

[0007] So-called soft chemistry is increasingly sought after to develop synthesis processes that are more ecological and that integrate more harmoniously into natural processes.

[0008] The applicant's patent application FR3112494A1 proposes a process for preparing inorganic micron capsules.

[0009] An object of the present invention is therefore to propose a method for synthesizing silica capsules of controlled micron size, which can advantageously allow the transport of lipophilic active ingredients. SUMMARY

[0010] To achieve this objective, according to one embodiment, a process for synthesizing silica microcapsules is provided, comprising an oily phase including at least one lipophilic active ingredient, comprising the following steps: - a) preparation of silica nuclei by hydrolysis of at least one silica precursor in water in an acidic catalytic medium, preferably the quantity of acid is chosen so as to be less than or equal to 0.05 acid equivalent relative to the silica precursor, - a') addition at the end of step a) or during step a) of an oily phase in an oil phase / silica precursor ratio greater than or equal to 1 / 1, preferably less than or equal to 1 / 7, - b) formation of a matrix phase by mixing at least one condensation agent selected from at least one branched or linear basic polycationic polymer selected from at least one of the following: polyethylene imines, polyamino acids, polyallylamines, propylene imine derivatives, polylysines, galactomannan polysaccharide derivatives, fructo-oligosaccharides and oligofructoses or a mixture, and at least one monovalent, divalent or trivalent anion selected from at least one of a phosphate salt, a tartrate salt and a citrate salt, a sulfate salt, or a nitrate salt, - c) condensation in basic medium of the silica nuclei obtained in step a) and of the oily phase by mixing under agitation with the matrix phase obtained in step b) at alkaline pH less than or equal to 10.

[0011] The present method surprisingly improves the performance of microcapsules. In particular, the invention allows for a significantly higher lipophilic active ingredient delivery rate than the prior art, notably by a ratio Silica precursor / active ingredients favoring the active ingredient within a selected range. Furthermore, the microcapsules obtained through this process exhibit optimized sealing, which notably increases user safety by reducing exposure to potential toxins and thus controlling their toxicity. BRIEF DESCRIPTION OF THE FIGURES

[0012] The aims, objects, features and advantages of the invention will become clearer from the detailed description of an embodiment thereof, which is illustrated by the following accompanying drawings in which:

[0013] [Fig.1] Fig.1 is a representative diagram of the particle size distribution by volume obtained by laser diffraction of a sample of hybrid silica microcapsule suspension containing CBD obtained with Example 1.

[0014] [Fig.2] Fig.2 is a representative optical microscopy image of hybrid silica microcapsules containing CBD obtained with Example 1.

[0015] [Fig.3] Fig.3 is a representative image obtained by electron microscopy scanning of hybrid silica microcapsules containing CBD obtained with Example 1.

[0016] [Fig.4A] Figures 4A and 4B are representative images by fluorescence optical microscopy (magnification x20) of samples of day cream containing CBD in hybrid silica microparticles obtained with example 1 before (A) and after spreading (B) releasing the CBD content.

[0017] [Fig.4B]

[0018] [Fig.5A] Figures 5A and 5B are representative HPLC chromatograms of samples of hybrid silica microparticles containing CBD obtained with example 1 after storage at 50°C (A) and 4°C (B).

[0019] [Fig.5B]

[0020] [Fig.6] Fig.6 is a diagram representing the particle size distribution per volume obtained by laser diffraction of a sample of suspension of hybrid silica microcapsules containing HE Pelargonium obtained with Example 2.

[0021] [Fig.7] Fig.7 is a representative electron microscopy image. scanning of hybrid silica microcapsules containing Pelargonium HE obtained with Example 2.

[0022] [Fig. 8A] Figures 8A and 8B are representative HPLC chromatograms of a sample of hybrid silica microparticles containing Pelargonium HE obtained with Example 2 (A) and of a sample of Pelargonium HE (B).

[0023] [Fig.8B]

[0024] [Fig.9] Fig.9 is a diagram representing the particle size distribution per volume obtained by laser diffraction of a sample of suspension of hybrid silica microcapsules containing Sweet Orange HE obtained with Example 3.

[0025] [Fig. 10] The [Fig. 10] is a representative optical microscopy image of hybrid silica microcapsules containing Sweet Orange HE obtained with Example 3.

[0026] [Fig. 11 A] Figures 11A and 11B are representative HPLC chromatograms of a sample of hybrid silica microparticles containing Sweet Orange HE obtained with Example 3 (A) and of a sample of Sweet Orange HE (B).

[0027] [Fig.llB]

[0028] [Fig. 12] The [Fig. 12] is a representative optical microscopy image of hybrid silica microcapsules containing Sweet Orange HE obtained with Example 4 and indicating the presence of unencapsulated Sweet Orange HE.

[0029] [Fig. 13] The [Fig. 13] is a representative diagram of the particle size distribution by volume obtained by laser diffraction of a sample of hybrid silica microcapsule suspension containing a perfumed composition intended for Personal Care obtained with Example 5.

[0030] [Fig. 14] [Fig. 14] is a representative scanning electron microscopy image of hybrid silica microcapsules containing a perfumed composition for Personal Care obtained with Example 5

[0031] [Fig. 15] The [Fig. 15] is a representative diagram of the particle size distribution by volume obtained by laser diffraction of a sample of suspension of hybrid silica microcapsules containing a perfumed composition intended for Personal Care obtained with Example 6.

[0032] [Fig. 16] The [Fig. 16] is a representative optical microscopy image of hybrid silica microcapsules containing HE Pelargonium obtained with Example 8 without the use of phosphate salts which tend to aggregate in the presence of gel.

[0033] [Fig. 17] The [Fig. 17] is a representative diagram of the particle size distribution by volume obtained by laser diffraction of a sample of suspension of silica microcapsules containing a perfumed composition obtained with Example 9.

[0034] [Fig. 18] The [Fig. 18] is a representative optical microscopy image of silica microcapsules containing a perfumed composition obtained with Example 9.

[0035] [Fig. 19] Fig. 19 is a representative diagram of the particle size distribution by volume obtained by laser diffraction of a sample of suspension of silica microcapsules containing a perfumed composition intended to be obtained with Example 10.

[0036] [Fig.20] Fig.20 is a representative optical microscopy image of silica microcapsules containing a perfumed composition obtained with Example 10 without the use of surfactant and under mild chemical conditions.

[0037] [Fig. 21] Fig. 21 is a representative thermogram of silica microcapsules containing a perfumed composition obtained with Example 10 and the reference perfume.

[0038] [Fig.22] Fig.22 is a diagram representing the distribution granulometric by volume obtained by laser diffraction of a sample of suspension of silica microcapsules containing Sweet Orange HE obtained with Example 11.

[0039] [Fig. 23] Fig. 23 is a representative optical microscopy image of silica microcapsules containing Sweet Orange HE obtained with Example 11 without the use of surfactant and under mild chemical conditions.

[0040] [Fig. 24] Fig. 24 is a representative thermogram of silica microcapsules containing Sweet Orange EO obtained with Example 11.

[0041] [Fig. 25] Fig. 25 is a representative optical microscopy image of silica microcapsules containing a perfumed composition obtained with Example 12 without the use of surfactant and under mild chemical conditions.

[0042] The drawings are given by way of example and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate understanding of the invention and are not necessarily to scale with practical applications. DETAILED DESCRIPTION

[0043] Before proceeding to a detailed review of embodiments of the invention, optional features that may be used in combination or alternatively are listed below:

[0044] By way of example, the oily phase is emulsified with water before its addition at the end of step a);

[0045] By way of example, the oily phase is mixed with the acidic catalytic medium before being mixed with at least one silica precursor, and then with water to form an emulsion;

[0046] By way of example, the oily phase is mixed with the acidic catalytic medium and at least one silica precursor before being mixed with water to form an emulsion;

[0047] By way of example, the oily phase includes at least one volatile lipophilic active ingredient;

[0048] By way of example, the oily phase includes at least one non-volatile lipophilic active ingredient;

[0049] By way of example, the oily phase comprises an oily solvent or in a mixture of oily solvents, for example, chosen from nonpolar solvents such as fats, vegetable oils, triglycerides, caprylic oils, caprylic oils, isopropyl myristate and more preferably from at least one of virgin castor oil, Miglyol® and coconut oil;

[0050] By way of example, the ratio of basic cationic polymers to silica monomers derived from the silica precursor is greater than or equal to 0.3 and less than or equal to 1; this range allows for adjustment of the condensation rate. Furthermore, it has been surprisingly observed that using less silica precursor and more basic cationic polymers results in better capsules;

[0051] By way of example, the process includes a step c'), subsequent to or simultaneous with step c) of condensation, comprising a step of functionalizing the capsules;

[0052] By way of example, the capsule functionalization step includes the addition of at least one silica precursor;

[0053] By way of example, the silica precursor for functionalization represents a maximum of 10%, preferably 7% by weight of the total weight of the silica precursor used in step a), preferably the functionalization represents a weight less than or equal to 5% of the total weight of the silica precursor used in step a);

[0054] By way of example, the condensation agent is added in step b) to be in an amount less than or equal to 100g / L in the matrix phase, preferably less than or equal to 50g / L, preferably less than or equal to 20g / L; steps a) to c) are carried out at a temperature compatible with the active or mixture of actives used.

[0055] By way of example, the silica precursor or a precursor mixture of step a) is selected from at least one of tetraethyl orthosilicate (TEOS), tetramethyl orthosilicate (TMOS), (3-Aminopropyl)triethoxysilane (APTES), sodium metasilicate, calcium silicate, trimethoxymethylsilane (MTMOS), triethoxymethylsilane (MTEOS), triethoxysilane, trimethoxysilane, triethoxy(ethyl)silane (ETEOS), trimethoxy(ethyl)silane (ETEOS), isobutyl(trimethoxy)silane, propyl(trimethoxy)silane, sodium orthosilicate;

[0056] By way of example, the silica precursor of step a) is chosen from at least one of a biogenic silica extract, sodium silicate or a natural source of ortho silicic acid;

[0057] By way of example, at least one silica precursor is added in step a) in an amount less than or equal to 6000mM, preferably at least one silica precursor is present in step c) in an amount less than or equal to 1000mM;

[0058] By way of example, the monovalent, divalent or trivalent anion is added in a concentration less than or equal to 300mM;

[0059] By way of example, the mixture from step b) is added to the nuclei obtained in step a);

[0060] By way of example, the process includes, after step c), a separation step d). capsules by centrifugation or filtration or decantation and possibly a step e) of washing the isolated capsules and possibly a step f) of drying the capsules.

[0061] The term "silica" refers to silicon dioxide or silica derivatives, for example, polysiloxanes. A siloxane is defined as saturated silicon-oxygen hydrides with unbranched or branched chains of alternating silicon and oxygen atoms (each silicon atom is separated from its nearest silicon neighbors by single oxygen atoms). The term "silica" also includes hybrid silica derivatives such as inorganic hydride materials, for example, organo-mineral or other inorganic materials.

[0062] The term "micron" means a capsule size between Ipm and 1000pm, more precisely between Ipm and 450pm, in the following description the terms micron, micrometric or microcapsule are understood in the same way.

[0063] According to one possibility, the silica produced by the present process is in the form of micron-sized capsules. Micron-sized means that the capsules have their largest dimension less than or equal to 1000 pm, more precisely between 1 pm and 1000 pm, more preferably between 1 pm and 450 pm. Preferably, the micron-sized capsules obtained by the process according to the invention have a size greater than or equal to 1 pm and less than or equal to 100 pm, and more preferably greater than or equal to 5 pm and less than or equal to 50 pm.

[0064] The capsules are made from a so-called amorphous material. Amorphous means that the form of the material is non-crystalline.

[0065] The capsules are advantageously spherical in shape, which represents an advantage for their safety.

[0066] The present invention relates to a process for synthesizing micron-sized silica capsules under mild chemical conditions.

[0067] Preferably, the process implements a bio-inspired synthesis.

[0068] The capsules obtained are advantageously biocompatible.

[0069] The capsules used according to the invention, given the choice of specific monomers, precursors and polymers, have the ability to be biodegradable,

[0070] The silica capsules obtained according to the embodiments of the invention have, in view of the choice of precursors, the capacity to be eliminated by dissolution in orthosilicic acid.

[0071] The capsules obtained by the process according to the invention are particularly suitable for cosmetic, human or veterinary pharmaceutical, phytosanitary, agri-food, laundry / household care, hygiene and health products, perfumery, biocides, biostimulants and repellents for human or veterinary use.

[0072] The silica capsules obtained according to one of the embodiments have a positive surface charge. This represents an advantage, particularly in terms of passive targeting of surfaces, cells, and / or tissues / epithelium that have a residual negative surface charge. The positive surface charge is especially advantageous for deposition on hair fibers for cosmetic applications or on textile fibers for laundry detergent and care applications.

[0073] According to the invention, the process makes it possible to produce capsules having a capsular morphology. Capsular means that the microcapsule comprises at least one hollow vesicle. In one possibility, the microcapsule is a hollow vesicle, or in another possibility, the microcapsule is a hollow vesicle containing hollow vesicles. That is to say, the capsule comprises a core surrounded by a solid shell, also called a husk or envelope.

[0074] According to the invention, the process is advantageously configured to encapsulate an oily phase in microcapsules.

[0075] The oily phase comprising at least one active ingredient.

[0076] The term "oil phase" refers to the phase containing a lipophilic active ingredient. The oil phase may consist of the lipophilic active ingredient itself, a mixture of lipophilic active ingredients, or the oil phase may comprise the lipophilic active ingredient in an oily solvent, a mixture of oily solvents, or a mixture of lipophilic active ingredients in an oily solvent or a mixture of oily solvents. The oil phase may include one or more additives.

[0077] In the following description, the term oily phase is used generically to encompass these different possibilities.

[0078] The oily phase exhibits lipophilic character. It is known to define lipophilic character by a LogP partition coefficient (octanol / water partition coefficient) greater than or equal to 3, preferably 4, more preferably 5. Advantageously, the oily phase exhibits a LogP partition coefficient greater than or equal to 3, preferably 4, more preferably 5.

[0079] The active ingredient is also referred to as the active substance.

[0080] According to the invention, the active ingredient is lipophilic.

[0081] A lipophilic active ingredient is understood to be an active substance having an affinity for a nonpolar solvent and which does not mix with a polar solvent such as water. Among the Nonpolar solvents, referred to above as oily solvents, include fats, vegetable oils, triglycerides, capric oils, caprylic oils, and isopropyl myristate. Specifically, the nonpolar solvent is chosen from at least one of the following: virgin castor oil (INCI: Ricinus communis seed oil | CAS: 8001-79-4 | EC: 232-393-8), Miglyol® (INCI: caprilic / capric triglyceride | CAS: 73398-61-5 / 65381-09-1 | EC: 277-452-2 / 265-724-3), and coconut oil. This property helps, for example, to ensure that the active ingredient remains in the oil phase.

[0082] Advantageously, the asset has a logP partition coefficient greater than or equal to 3, preferably 4, more preferably 5.

[0083] According to an embodiment in which the oily phase comprises several active ingredients, i.e. a mixture of active ingredients, it is preferred that at least 50%, preferably 60% and even more preferably 80% of the active ingredients have a partition coefficient logP greater than or equal to 3, preferably 4, more preferably 5.

[0084] The active ingredient can be of various kinds depending on the application. The active ingredient comprises at least one active molecule or a mixture of active molecules. The active ingredient is chosen, for example, from a fragrance active ingredient or a fragrance composition, or a plant extract or a natural or synthetic cosmetic active ingredient, such as, for example, a sunscreen, a plant protection product, an essential oil, or a pheromone(s) or a mixture of pheromones.

[0085] According to one possibility, the active ingredient comprises at least one perfumer substance. The active ingredient is a perfume or a perfumer composition.

[0086] According to one possibility, the active ingredient comprises at least one or is made up of an essential oil.

[0087] The lipophilic active ingredient is soluble in a fat, oil, or nonpolar solvent. This property ensures that the active ingredient is dispersed in the oil phase.

[0088] The lipophilic active ingredient may be volatile. A volatile lipophilic active ingredient is defined as a substance capable of vaporizing from a liquid to a gaseous state. Vapor pressure and boiling point are known indicators of a substance's volatility. For example, the active ingredient has a vapor pressure greater than 0.01 kPa at a temperature of 20 °C or a boiling point below 250 °C at a standard pressure of 101.3 kPa. Examples of volatile lipophilic active ingredients include essential oils (e.g., sweet orange), terpene derivatives (e.g., limonene), and tetrahydromyrcenol.

[0089] The lipophilic active ingredient may be non-volatile. A non-volatile lipophilic active ingredient is defined as a substance that is difficult to vaporize from a liquid to a gaseous state. For example, the active ingredient may have a vapor pressure of 0.01 kPa or less at a temperature of 20°C or a boiling point of 250°C or more at a standard pressure of 101.3 kPa. An example of a non-volatile lipophilic active ingredient is cedryl acetate.

[0090] The encapsulation yield is understood to be the ratio of the encapsulated oily phase to the mass of oily phase to be encapsulated. It is expressed as a percentage.

[0091] The carry-through rate means the mass percentage of oily phase contained in the capsules.

[0092] Overall yield is defined as the ratio of the mass of capsules obtained to the theoretical mass of capsules expected. The theoretical mass of capsules expected is the sum of the mass of oil phase to be encapsulated and the expected quantity of encapsulation material, the encapsulation material being derived from the silica precursor.

[0093] The process advantageously comprises 3 steps.

[0094] Preferably, the three steps: step a), step b) and step c) are carried out in an aqueous medium.

[0095] According to one embodiment, the process includes a step a) of preparing the silica nuclei. According to the invention, step a) is a hydrolysis of at least one silica precursor. Step a) is carried out in an aqueous medium and advantageously in an acid-catalyzed aqueous medium.

[0096] According to one embodiment, at least one silica precursor is chosen from among precursors: - of the siloxy type corresponding to the formula (R)xSi(O-Rl)4 x with Rl = alkyl (C1-C4) or hydroxyl group, and R = alkoxy, hydrogen, linear or branched alkyl group or an alkene, which may have a functional group such as amine, carboxyl, thiol, hydroxyl, epoxy, and / or - of the inorganic orthosilicate type corresponding to the formula SiO4M or (M2O)X •(SiO2)y with x=l or 2, y = 1 or 2 with M=metal such as Ca, Na for example, Ca2SiO4 or 2CaOSiO2, or Na4SiO4, and / or - of the organic orthosilicate type such as (CH3)4SiO4 and (CH2CH3)4SiO4

[0097] Preferably, at least one silica precursor is advantageously chosen from at least one of tetraethyl orthosilicate (TEOS), tetramethyl orthosilicate (TMOS), (3-Aminopropyl)triethoxysilane (APTES), sodium metasilicate, calcium silicate, trimethoxymethylsilane (MTMOS), triethoxymethylsilane (MTEOS), triethoxysilane, trimethoxysilane, triethoxy(ethyl)silane (ETEOS), trimethoxy(ethyl)silane (ETMOS), isobutyl(trimethoxy)silane, propyl(trimethoxy)silane, sodium orthosilicate.

[0098] According to one possibility, the silica precursor is a biogenic silica extract such as, for example, from rice or diatom residues, sodium silicate, or a natural source of orthosilicic acid.

[0099] Preferably, the amount of silica precursor added in step a) is less than or equal to 6000 mM, preferably less than or equal to 5000 mM, more preferably less than or equal to 4500 mM.

[0100] Preferably, the amount of silica precursor in step c) is less than or equal to 1000mM, more preferably less than 800mM, preferably less than or equal to 450mM.

[0101] According to one embodiment, the amount of acid added is advantageously less than or equal to 0.05 acid equivalent. More precisely, the amount of acid is less than or equal to 0.02, more preferably greater than or equal to 0.001, and less than or equal to 0.015 acid equivalent. The amounts of acid are given in acid equivalent relative to the silica precursor.

[0102] According to one possibility, the acid is chosen from a weak carboxylic acid or a strong acid. Preferably, the acid is chosen from formic acid, acetic acid or hydrochloric acid.

[0103] Advantageously, the pH of the aqueous medium in which the nuclei are prepared is at pH less than or equal to 5, preferably less than or equal to 4, preferably less than or equal to 3. Advantageously, the pH is less than or equal to 3 with a minimum acid concentration so as to place it in an acid-catalyzed medium allowing to ensure mild chemical conditions for the process.

[0104] By way of example, nuclei are formed at most of a few dozen atoms, for example, a silica nuclei has a size on the order of a few nanometers in diameter and preferably less than 20 nm.

[0105] The process according to the invention is advantageously configured to encapsulate the active ingredient in a microcapsule, the active ingredient, more generally the oily phase, is in the core of the capsule.

[0106] To this end, the process according to the invention includes the addition of an oily phase comprising, or consisting of, at least one lipophilic active ingredient.

[0107] The addition of the oily phase is carried out either during step a), or at the end of step a) and before step c) described below.

[0108] According to a first possibility, the oil phase is added to the nuclei obtained in step a). Advantageously, the oil phase is added to the nuclei obtained in step a) before mixing with the matrix phase obtained in step b). Advantageously, the oil phase is added at the end of step a), when the nuclei are formed, so as to limit disturbances in nuclei formation during step a). This process advantageously leads to the production of capsules with a capsular morphology. In particular, this process ensures a limited contact time between the active ingredient and the acidic medium, which is very useful when the active ingredient is sensitive to acids.

[0109] According to a second possibility, the oil phase is added to the nuclei obtained in step a). The silica precursor is mixed with the acidic catalytic medium. Nuclei begin to form. The oil phase is advantageously added to the water. An emulsion of the oil phase in the aqueous phase, which does not contain the silica precursor or the acid, is formed by stirring. The silica precursor in the acidic catalytic medium, having formed nuclei, is then added to the emulsion, preferably under stirring. The silica precursor in the acidic catalytic medium has formed nuclei which, upon mixing with the emulsion, arrange themselves at the oil / aqueous phase interface, thereby stabilizing the emulsion.

[0110] According to a third possibility, the oil phase is added in step a) of nucleus preparation. The oil phase is advantageously added to the aqueous acidic catalytic medium. The mixture of the oil phase with the aqueous acidic catalytic medium, and not containing the silica precursor, is formed by stirring. The silica precursor is then added to the mixture. Nuclei begin to form. Then the mixture is added to water, advantageously under stirring, to form an emulsion.

[0111] According to a fourth possibility, the oil phase is added in step a) of nucleus preparation. The oil phase is advantageously added to the silica precursor in an aqueous acidic catalytic medium. The nuclei begin to form. The nuclei-oil phase mixture is added to water under stirring to form an emulsion of the oil phase in the aqueous phase containing the nuclei, advantageously by stirring.

[0112] The oil phase is mixed with an aqueous phase under agitation. For example, the oil phase-aqueous phase mixture, the aqueous phase preferably being water, is agitated for a minimum of 30 seconds and up to 5 minutes. For example, the mixture is agitated at a minimum speed of 2000 rpm and up to 10000 rpm. For example, the mixture has a mass concentration of active ingredient(s) in water of approximately 10% by weight.

[0113] According to the invention, the oily phase is added in a minimum silica precursor / oily phase ratio of 1 / 1 and a maximum of 1 / 7, for example 1 / 4.2.

[0114] Surprisingly, this ratio makes it possible to ensure a rate of removal of the oily phase greater than 85%.

[0115] Advantageously, the process does not involve the addition of a surfactant. The process according to the invention does not require a surfactant to stabilize the droplets of the oil phase during emulsification prior to capsule formation.

[0116] According to one embodiment, the process includes a step b) of forming a matrix phase. The matrix phase is understood to be the phase intended to allow the formation of silica. The matrix is ​​formed by mixing at least one condensation agent and at least one monovalent, divalent, or trivalent anion or a mixture of monovalent, divalent, or trivalent anions.

[0117] The condensing agent is advantageously a branched or linear basic polycationic polymer. This represents an advantage over the more conventional use of a strong base such as ammonia. Choosing a basic polycationic polymer eliminates the need to adjust the pH by adding a strong base such as ammonia to initiate condensation. This results in a more environmentally friendly, mild chemical process. The process does not include a step solely dedicated to pH adjustment.

[0118] Preferably, the polymer is chosen to have a weight less than or equal to 800 kDa. According to one aspect, said polymer comprises polyamino acids, in particular basic ones such as polyarginines, polylysines and polyhistidines, but also polyallylamines, polyethylene imines (PEI), polypropylene imines, derivatives of polysaccharides of the galactomannan type, fructo-oligosaccharides, oligofructoses or mixtures thereof.

[0119] The condensation agent may be derived from the chemical modification of one of the polymers mentioned above in order to modulate its physico-chemical properties.

[0120] According to one aspect, the condensation agent is more precisely a polymer rich in primary, secondary or tertiary amine functions, that is to say comprising a number of amine residues greater than or equal to 3.

[0121] In the case of branched or linear polyethylene imines (PEIs), they consist of the repeating ethylene imine type (C2H5N) unit with a molar mass of 43.04 g / mol. By way of example, a polymer may be diethylenetriamine or any of its higher homologues.

[0122] The condensation agent may also be a branched PEI of the following formula: H(NHCH2CH2)nNH2)n of molecular weight between 10000 and 750000, in particular between 25000 and 750000 or a mixture of PEIs such as for example mixtures of PEIs at 10000kDa and 25kDa.

[0123] According to one aspect, the condensation agent is a polyamine dendrimer of generation higher than 1 containing motifs of type [-CH2CH2N(CH2CH2CH2NH2)2]2, for example DAB-Am-4, Polypropylenimine tetramine dendrimer, generation 1.

[0124] In the case of galactomannan polysaccharide derivatives, modified or unmodified guar gum is preferred. The guar gum may be modified by a synthetic or non-synthetic amine basic group, for example a quaternary ammonium group.

[0125] In the case of oligofructose derivatives, inulin is preferred. Inulin may be modified by a basic amine group, synthetic or not, for example a quaternary ammonium group.

[0126] According to one possibility, the condensation agent is a mixture of PEI and guar and / or inulin.

[0127] Preferably, the condensing agent is added in step b) to achieve a final mass concentration in step b) of less than or equal to 100 g / L, more precisely less than or equal to 50 g / L, preferably less than or equal to 20 g / L. The process according to the invention makes it possible to use a small amount of condensing agent and thus obtain a basic condensation pH as close as possible to physiological conditions, preferably on the order of pH 10, preferably on the order of pH 9, more preferably on the order of pH 8.

[0128] The condensation agent is advantageously selected to have chemical groups favorable to the formation of non-covalent interactions such as, for example, electrostatic and / or hydrogen bonds. In this way, the condensation agent assists the polymerization of silica monomers in a controlled manner.

[0129] The condensation agent is advantageously a bio-inspired or natural or bio-based polymer.

[0130] The condensing agent is advantageously recycled at the end of the process according to the invention. Recycling of the condensing agent is carried out by processes known to those skilled in the art, such as exclusion gel filtration and / or ion-exchange resins, and ultrafiltration using membranes with suitable limiting nominal molecular weights. Recycling the condensing agent represents a clear advantage.

[0131] The condensation agent, such as PEI or modified or unmodified guar gum, acts both as a catalyst accelerating the condensation reaction and as a matrix that controls the reaction and the formation of capsules for the growth of nuclei from nucleation points provided by the polymer-anion association such as phosphate.

[0132] According to one embodiment, at least one monovalent, divalent, trivalent anion is an anionic salt. Preferably, the monovalent, divalent, trivalent anion is chosen from at least one of a phosphate salt, a citrate salt, a tartrate salt, a sulfate salt, or a nitrate salt.

[0133] By way of example, the phosphate salt is chosen from sodium phosphate, magnesium phosphate, potassium phosphate, calcium phosphate.

[0134] By way of example, the citrate salt is chosen from sodium citrate, potassium citrate, calcium citrate, magnesium citrate.

[0135] By way of example, the tartrate salt is chosen from sodium tartrate, potassium tartrate, calcium tartrate, sodium and potassium tartrate, choline tartrate, ammonium tartrate.

[0136] Preferably, the monovalent, divalent, or trivalent anion is added in step b) to achieve a final concentration less than or equal to 300 mM, more precisely 200 mM. The addition of at least one anion or a mixture of anions according to this concentration selection makes it possible to obtain the effect of the anion while limiting the impact on the pH of the condensation medium.

[0137] At least one monovalent, divalent or trivalent anion, or mixture of anions, is added to the condensation agent in particular to ensure electrostatic interactions with the condensation agent and to allow the formation of the matrix, in particular to control the formation of capsules.

[0138] According to one embodiment, the process includes a step c) of condensation in a basic medium. The condensation step ensures the controlled condensation of the nuclei obtained in step a) using the matrix obtained in step b). The condensation step allows the nuclei obtained in step a) to form a solid network to obtain capsules.

[0139] Step c) advantageously comprises mixing the silica nuclei and oil phase with the matrix, preferably under agitation.

[0140] According to one possibility, the nuclei obtained in step a) supplemented with the oily phase, the whole being called the hydrolysis phase, are added to the matrix obtained in step b), also called the matrix phase.

[0141] According to another possibility, the matrix phase obtained in step b) is added to the nuclei obtained in step a) supplemented with the oily phase.

[0142] According to one embodiment, the hydrolysis phase is added in a single portion to the matrix phase. In one possibility, the addition is carried out with a controlled flow rate or directly in a single step without control.

[0143] Advantageously, step c) of condensation is carried out at basic pH, said to be moderate, i.e. less than or equal to 10. Preferably, at pH less than or equal to 9, even more preferably less than or equal to 8 and greater than 7.

[0144] According to an advantageous embodiment of the present invention, the synthesis process, more preferably steps a), b), and c), and optionally the functionalization step described below, is carried out without heating or cooling. Preferably, the process is configured to maintain a temperature compatible with the active ingredient or mixture of active ingredients used. In one possibility, the addition of the silica precursor can be carried out in one or more stages, with or without cooling.

[0145] According to one embodiment, the process according to the invention for synthesizing micron-sized silica capsules advantageously comprises a step c'), subsequent to or simultaneous with the condensation step c), comprising a capsule functionalization step. If step c') is subsequent to step c), it is advantageously directly subsequent, meaning that steps c) and c') are successive, preferably without an intermediate step. The functionalization step modifies the surface of the silica capsules to achieve targeted surface functionalization and impart new properties to the capsules. The functionalization step advantageously includes the addition of a silica precursor.According to one example, the silica precursor is chosen from at least one of the following: TEOS (tetraethyl orthosilicate), TMOS (tetramethyl orthosilicate), MTMOS (methyltrimethoxysilane), MTEOS (methyltriethoxysilane), ETEOS (ethyltriethoxysilane), ETMOS (ethyltrimethoxysilane), APTES ((3-aminopropyltriethoxysilane), sodium orthosilicate or sodium metasilicate. The silica precursor in the functionalization step may be the same as or different from the silica precursor used in step a).

[0146] According to one possibility, the functionalization step advantageously includes the addition of an organosilane-type silica precursor as a coupling agent. In one example, the silica precursor is selected from at least one of a silica precursor having at least one coupling agent group selected from an amino, isocyanate, mercapto, vinyl, or acrylate group. For example, the coupling agent precursor is APTES ((3-Aminopropyl)triethoxysilane), vinyltrimethoxysilane, vinyltriethoxysilane, glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, or 3-mercaptopropyltrimethoxysilane. The silica precursor in the functionalization step may be the same as or different from the silica precursor used in step a).

[0147] According to one embodiment, the process of the invention for synthesizing micron-sized silica capsules advantageously comprises a step d), subsequent to the condensation step c), preferably subsequent to step c'), if present, comprising a capsule separation step. The separation step allows the microcapsules to be dissociated from any uncondensed nuclei, matrix phase, and / or residual active ingredients. The capsule separation step can, for example, be carried out by centrifugation, frontal filtration, decantation, or tangential flow filtration.

[0148] According to one embodiment, the process according to the invention for synthesizing micrometric silica capsules comprises a step e), subsequent to step c), preferably subsequent to step c') if present, and optionally to separation step d) which allows purification of the silica microcapsules by Washing or chemical extraction. The purification step is intended to remove organic residues from the process. However, due to the synthesis process of the invention, carried out under mild chemical conditions, particularly bio-inspired and advantageously without organic solvents, any organic residues are non-harmful and do not affect the properties of the capsules. Therefore, they do not necessarily need to be removed from the microcapsules and may even impart new properties to the capsules, such as deposition. For example, cationic polymers do not necessarily need to be removed from the microcapsules to promote deposition on coated surfaces. As an example, the purification step can be performed by washing and / or centrifugation cycles.

[0149] According to one embodiment, the process according to the invention for synthesizing micrometric silica capsules comprises a microcapsule drying step f) subsequent to the condensation step c) preferably subsequent to step c') if present, and optionally separation steps d) and purification steps e). The drying step makes it possible to obtain microcapsules in dry form, which can be an advantage in terms of storage, for example. The drying step can be carried out by atomization or spray drying. Advantageously, this atomization or spray-drying step can lead to a mechanical shaping step of the silica and active ingredient microcapsules.

[0150] Example 1.

[0151] 12.6 g of broad spectrum CBD 32% (coconut oil) are emulsified in 46.7 g Water is mixed with a high-shear mixer (Turrax T25). Under shear, 5.7 g of pre-hydrolyzed MTEOS precursor under catalytic acid conditions (pH 1.5) are mixed into the emulsion until the desired emulsion size is achieved. The emulsion is then treated with 30.3 g of aqueous solution containing 1.1 g of polyethylene imine 25 kDa and 2.0 g of sodium phosphate salts. Capsules are formed instantaneously and exhibit sizes between 1 and 50 µm, depending on the shear force and the geometry of the dispersing tool used. The capsules are separated by centrifugation. The particle size distribution is measured by laser diffraction particle size analysis (Malvern Mastersizer 3000E, [Fig. 1]). Particle morphology is determined by optical microscopy and SEM. The particles have a spherical morphology ([Fig.2]) and a core / shell-like structure ([Fig.3]). 14.8 grams of broad-spectrum CBD microcapsules are obtained.The oil content of the capsules is 81% by weight after extraction. The broad-spectrum CBD content is 27.8% (by HPLC assay).

[0152] Fluorescence labeling

[0153] Capsules obtained with the Example were treated with 0.25 mL of a FITC-APTES complex in ethanol (0.085% mol equivalent silicon) before separation for fluorescence labeling.

[0154] Day cream formulation 0.3% CBD

[0155] Capsules obtained with Example 1 were formulated as a day cream. The aqueous phase A and oily phase B (see Table 1 Composition) are prepared separately by mixing the ingredients under magnetic stirring (600 rpm) and heating in a water bath at 70°C. Phase B is added to phase A under stirring with a deflocculating rod (800 rpm). The oil / water emulsion is maintained under stirring and heating for 10 min, then cooled to 30°C under simple magnetic stirring (500 rpm).

[0156] Fluorescence microscopy obtained from fluorescent microcapsules obtained with Example 1 allows observation of the conservation of the structure of the particles after formulation ([Fig.4A]) and the breaking capacity on spreading ([Fig.4B]). [Tables 1] INCI Name Mass (g) Phase A Aqua 35.2 Glycerin 1.5 Cannabidiol (microencap 0.3 sulé) Phase B Glyceryl stearate 6 Stearyl alcohol 1 Ceteareth-20 1 Caprylic / capric TG 4 Prunus dulcis oil 1

[0157] Stability of microencapsulated and formulated CBD

[0158] The stability of microencapsulated CBD samples obtained with Example 1 in suspension in water and in the day cream formulation was confirmed by HPLC assay after storage for up to 8 weeks at 37°C (accelerated conditions) and up to 10 days at 50°C (stressed conditions) with no significant degradation (<5%) of the CBD peak (TR: 2.9 min) compared to the control stored at 4°C (Figures 5A and 5B).

[0159] Example 2.

[0160] 43.9 g of Pelargonium HE in 81.5 g of Miglyol 812 are emulsified in 513 g water with a high-shear mixer (Turrax T25). Under shear, 57.2 g of MTEOS precursor, previously hydrolyzed under catalytic acid conditions (pH 1.5), are mixed into the emulsion until the desired emulsion size is obtained, then the emulsion is treated with 280 g of aqueous solution containing 11.2 g of Polyethylene imine 25 kDa and 21.0 g of sodium phosphate salts were used. The capsules formed instantaneously and ranged in size from 1 to 50 µm depending on the shear force and geometry of the dispersing tool used. Particle size distribution was measured by laser granulometry (Malvern Mastersizer 3000E, [Fig. 6]). Particle morphology was determined by SEM. The particles had a spherical morphology and a core / shell structure ([Fig. 7]). The capsules were separated by centrifugation. 148.6 grams of Pelargonium EO microcapsules were obtained. The oil phase content of the capsules was 85.5% by weight after extraction. The Pelargonium EO content was 29.9% by HPLC assay and consistent with the Pelargonium EO profile (Figures 8A and 8B).

[0161] Example 3.

[0162] 43.9 g of sweet orange essential oil in 81.5 g of miglyol 812 are emulsified in 513 g of water with a high-shear mixer (Turrax T25). Under shear, 57.2 g of pre-hydrolyzed MTEOS precursor under catalytic acid conditions (pH 1.5) are mixed into the emulsion until the desired emulsion size is obtained. The emulsion is then treated with 280 g of aqueous solution containing 11.2 g of polyethylene imine 25 kDa and 21.0 g of sodium phosphate salts. Capsules are formed instantaneously and have sizes ranging from 1 to 50 µm depending on the shear force and the geometry of the dispersing tool used. The particle size distribution is measured by laser dispersive X-ray spectroscopy (Malvern Mastersizer 3000E, [Fig. 9]). Particle morphology is determined by SEM. The particles have a spherical morphology and a core / shell structure ([Fig. 10]). The capsules are separated by centrifugation. 111.0 grams of Sweet Orange HE microcapsules are obtained. The content of the capsules in the oil phase is 89.7% by weight after extraction. The sweet orange essential oil content is 31.6% by HPLC assay and conforms to the sweet orange essential oil profile (Figures 11A and 11B).

[0163] Example 4.

[0164] 2.21 g of sweet orange essential oil and 4.10 g of Miglyol 812 are emulsified in 54.24 g Water is mixed with a high-shear mixer (Turrax T25). Under shear, 9 mL of pre-hydrolyzed MTEOS precursor under catalytic acid conditions (pH 1.5) are mixed into the emulsion until the desired emulsion size is achieved. The emulsion is then treated with 15 g of aqueous solution containing 1.127 g of polyethylene imine 25 kDa and 13.05 g of sodium phosphate salts. Capsules are formed instantaneously and observed in the presence of a significant amount of unencapsulated essential oil, as seen by optical microscopy ([Fig. 12]).

[0165] Example 5.

[0166] 3.2 g of perfume composition (1) in 1.0 g of Miglyol 812 are emulsified in 42.3 g of water with a high-shear mixer (Turrax T25). Under shear, 8.0 g of pre-hydrolyzed MTEOS precursor under catalytic acid conditions (pH 1.5) are mixed with the emulsion until the desired emulsion size is achieved. The emulsion is then treated with 42.1 g of aqueous solution containing 1.7 g of polyethylene imine 25 kDa and 3.1 g of sodium phosphate salts. Capsules are formed instantaneously and exhibit sizes ranging from 1 to 50 µm, depending on the shear force and geometry of the dispersing tool used. After 5 minutes, 0.45 g of APTES are added to the mixture during homogenization. The particle size distribution is measured by laser diffraction particle size analysis (Malvern Mastersizer 3000E, [Fig. 13]). Particle morphology is determined by SEM. The particles have a spherical morphology and a core / shell structure ([Fig. 14]). The capsules are separated by centrifugation. 5.7 grams of microcapsules are obtained. The content of the capsules in the oil phase is 52% by weight after extraction.

[0167] Example 6.

[0168] 17.3 g of perfume composition (1) in 5.8 g of miglyol are emulsified in 23.2 g of water with a high-shear mixer (Turrax T25). Under shear, 8.0 g of pre-hydrolyzed MTEOS precursor under catalytic acid conditions (pH 1.5) are mixed into the emulsion until the desired emulsion size is achieved. The emulsion is then treated with 42.1 g of aqueous solution containing 1.7 g of polyethylene imine 25 kDa and 3.1 g of sodium phosphate salts. Capsules are formed instantaneously and exhibit sizes between 1 and 50 µm, depending on the shear force and the geometry of the dispersing tool used. After 5 minutes, 0.45 g of APTES are added to the mixture during homogenization. The particle size distribution is measured by laser diffraction particle size analysis (Malvern Mastersizer 3000E, [Fig. 15]). The capsules are separated by centrifugation. 21.2 grams of microcapsules are obtained. The content of the capsules in the oil phase is 86% by weight after extraction.

[0169] Example 7.

[0170] Impact of pH on the size of the particles obtained

[0171] 2.2 g of perfume composition (2) in 4.1 g of castor oil are emulsified in 54.2 g of water are mixed with a high-shear mixer (Turrax T25). Under shear, 8.0 g of pre-hydrolyzed MTEOS precursor under catalytic acid conditions (pH 0.5 or 1.6) are mixed into the emulsion until the desired emulsion size is achieved. The emulsion is then treated with 28.1 g of aqueous solution containing 1.1 g of polyethylene imine 25 kDa and 3.1 g of sodium phosphate salts. Capsules are formed instantaneously and have sizes ranging from 1 to 100 µm, depending on the shear force and the geometry of the dispersing tool used. The particle size distribution is measured by laser dispersive sizing (Malvern Mastersizer 3000E). The average particle size distribution is reduced from 29 µm to 11.5 µm by increasing the pH. After 5 minutes, 0.45 mL of APTES is added to the mixture. Under homogenization, the capsules are separated by centrifugation. 8-9.0 grams of microcapsules are obtained. The oil phase content of the capsules is 60% by weight after extraction.

[0172] Example 8.

[0173] 4.4 g of Pelargonium HE in 8.2 g of Miglyol 812 are emulsified in 51.3 g of water with a high-shear mixer (Turrax T25). Under shear, 6.4 ml of pre-hydrolyzed MTEOS precursor under catalytic acid conditions (pH 1.6) are mixed into the emulsion until the desired emulsion size is obtained. The emulsion is then treated with 28.0 g of aqueous solution containing 1.1 g of polyethylene imine 25 kDa. Capsules are formed instantaneously and have sizes ranging from 1 to 50 µm, depending on the shear force and the geometry of the dispersion tool used. Particle morphology is determined by optical microscopy. The particles have a spherical morphology and a core / shell structure and are observed in the presence of a gel that promotes particle aggregation ([Fig. 16]). The capsules are separated by centrifugation. 10.0 grams of Pelargonium HE microcapsules are obtained. The content of the capsules in the oil phase is 88.5% by weight after extraction.

[0174] Example 9.

[0175] 6.7 g of TEOS precursor are added to 3.8 g of perfume composition (1), 2.0 g of Miglyol 812 and 0.85 g of water at pH 0.5 were mixed for 15 minutes. The resulting mixture was then blended with 62.5 g of water under high shear to form an emulsion to the desired size. This emulsion was then treated with 23.6 g of an aqueous solution containing 0.8 g of polyethylene imine 25 kDa and 2.1 g of sodium phosphate salts. Capsules were formed instantaneously and exhibited sizes ranging from 1 to 50 µm, depending on the shear force and the geometry of the dispersing tool used. The particle size distribution was measured by laser granulometry (Malvern Mastersizer 3000E, [Fig. 17]). Particle morphology was determined by optical microscopy. The particles had a spherical morphology and a core / shell structure ([Fig. 18]). The capsules were separated by centrifugation. 3.4 grams of microcapsules are obtained. The content of the capsules in the oil phase is 72.6% by weight after extraction.

[0176] Example 10.

[0177] 6.7 g of TEOS precursor are added to 2.3 g of perfume composition (1), 3.5 g of Miglyol 812 and 0.85 g of water at pH 0.5 were mixed for 15 minutes. The resulting mixture was then blended with 62.5 g of water under high shear to form an emulsion of the desired size. This emulsion was then treated with 23.6 g of an aqueous solution containing 0.8 g of polyethylene imine 25 kDa and 2.1 g of sodium phosphate salts. The capsules were formed instantly and ranged in size from 1 to 50 µm. depending on the shear force and geometry of the dispersion tool used. Particle size distribution is measured by laser granulometry (Malvern Mastersizer 3000E, [Fig. 19]). Particle morphology is determined by optical microscopy. The particles have a spherical morphology and a core / shell structure ([Fig. 20]). The capsules are separated by centrifugation. 4.0 grams of microcapsules are obtained. The content of the capsules in the scented oil phase is 89% by weight by TGA analysis (Mettler Toledo TGA2) based on mass loss between 110-400°C (10°C / min ramp between 25 and 800°C, [Fig. 21]).

[0178] Olfactory performance of perfumed microcapsules

[0179] Formulation in base with surfactant:

[0180] Capsules obtained with Examples 9 and 10, in the form of a water suspension, were formulated with an all-purpose cleaner base (Garlic Purpose Cleaner or APC) at 0.3% fragrance equivalent. A 0.5 mL sample was applied and spread evenly on a smooth 8.3 cm x 10 cm surface. The surface was left to air dry for 4 hours at room temperature and then evaluated by a minimum of 4 panelists. The fragrance intensity was rated from 0 to 10. A score of 5 indicated that the fragrance was easily detectable with medium intensity, and an intensity of 10 indicated very strong intensity. After 4 hours, the fragrance was detected and its odor precisely described. After rubbing the surface with a precision wiper, a stronger intensity was obtained.The intensity is even stronger for the product containing the fragrance in capsules, indicating that the capsules are capable of effectively retaining a fragrance composition and delivering an enhanced experience of a scented product. [Tables 2] Before rubbing After rubbing Example 9 3-4 +3 Example 10 3-4 +2 Free perfume 3-4 0

[0181] Formulation in base with surfactant in a rinse-off application (shampoo):

[0182] Capsules obtained in Example 9, in the form of a suspension in water, were formulated as a shampoo base with 0.4% fragrance. A 1.5g application of shampoo is made to a strand of hair (7g), which is then rinsed under lukewarm water. This application is repeated twice. The strand is then towel-dried and air-dried for 5 hours before being evaluated by a minimum of 4 panelists. The fragrance intensity is rated from 0 to 10. A score of 5 indicates that the fragrance is easily detectable with medium intensity, and a score of 10 indicates very strong intensity. After 5 hours, the fragrance is detected and its odor precisely described (intensity 3-4). After rubbing the wick with the fingers, a stronger intensity (+2) is obtained, indicating that the capsules are able to effectively retain a perfumed composition and deliver an improved experience of a rinsed perfumed product.

[0183] Example 11.

[0184] 6.7 g of TEOS precursor are added to 2.3 g of Sweet Orange EO, 3.5 g of Miglyol 812 and 0.85 g of water at pH 0.5 were mixed for 15 minutes. The resulting mixture was blended with 62.5 g of water under high shear to form an emulsion to the desired size. The emulsion was then treated with 23.6 g of an aqueous solution containing 0.8 g of polyethylene imine 25 kDa and 2.1 g of sodium phosphate salts. Capsules were formed instantaneously and exhibited sizes between 1 and 50 µm, depending on the shear force and the geometry of the dispersing tool used. The particle size distribution was measured by laser granulometry (Malvern Mastersizer 3000E, [Fig. 22]). Particle morphology was determined by optical microscopy. The particles had a spherical morphology and a core / shell structure ([Fig. 23]). The capsules were separated by centrifugation, yielding 4.2 grams of microcapsules.The content of the capsules in the oil phase is 84% ​​by weight by TGA analysis (Mettler Toledo TGA2) based on the mass loss between 110-400°C (ramp 10°C / min between 25 and 800°C, [Fig.24]).

[0185] Example 12.

[0186] 2.3 g of perfume composition (1) in 3.5 g of Miglyol 812 are added to 6.7 g of precursor TEOS. The mixture is stirred for 15 minutes after the addition of 0.85 g of water at pH 0.5. The resulting mixture is blended with 62.5 g of water under high shear to form an emulsion to the desired size. The emulsion is then treated with 23.6 g of aqueous solution containing 0.8 g of polyethylene imine 25 kDa and 2.1 g of sodium phosphate salts. Capsules are formed instantaneously and have sizes ranging from 1 to 50 µm, depending on the shear force and the geometry of the dispersing tool used. Particle morphology is determined by optical microscopy. The particles have a spherical morphology and a core / shell structure ([Fig. 25]). The capsules are separated by centrifugation. 4.0 grams of microcapsules are obtained. The oil phase content of the capsules is 84% ​​by weight per extraction.

Claims

Demands

1. A process for the synthesis of silica microcapsules comprising an oil phase comprising at least one lipophilic active comprising the following steps: a) preparation of silica nuclei by hydrolysis of at least one silica precursor in water in an acidic catalytic medium, preferably the amount of acid is chosen so as to be less than or equal to 0.05 acid equivalent relative to the silica precursor, a') addition at the end of step a) or during step a) of an oil phase in an oil phase / silica precursor ratio greater than or equal to 1 / 1, preferably less than or equal to 1 / 7.b) formation of a matrix phase by mixing at least one condensation agent selected from at least one branched or linear basic polycationic polymer selected from at least one of the polyethylene imines, polyamino acids, polyallylamines, propylene imine derivatives, polylysines, galactomannan polysaccharide derivatives, fructo-oligosaccharides and oligofructoses or a mixture, and at least one monovalent, divalent or trivalent anion selected from at least one of a phosphate salt, a tartrate salt and a citrate salt, a sulfate salt, or a nitrate salt, c) condensation in a basic medium of the silica nuclei obtained in step a) and of the oily phase by mixing under stirring with the matrix phase obtained in step b) at an alkaline pH less than or equal to 10.

2. A method according to the preceding claim wherein the oily phase is emulsified with water before its addition at the end of step a).

3. A process according to claim 1 wherein the oily phase is mixed with the acidic catalytic medium before being mixed with at least one silica precursor, and then with water to form an emulsion.

4. A process according to claim 1 wherein the oily phase is mixed with the acidic catalytic medium and at least one silica precursor before being mixed with water to form an emulsion.

5. A process according to any one of the preceding claims wherein the oily phase comprises at least one volatile lipophilic active ingredient.

6. A process according to any one of claims 1 to 4 wherein the oily phase comprises at least one non-volatile lipophilic active ingredient.

7. A process according to any one of the preceding claims wherein the oily phase comprises an oily solvent or a mixture of oily solvents.

8. A process according to any one of the preceding claims wherein the ratio of basic cationic polymers to silica monomers from the silica precursor is greater than or equal to 0.3 and less than or equal to 1.

9. A method according to any one of the preceding claims comprising a step c'), subsequent to or simultaneous with step c) of condensation, comprising a step of functionalizing the capsules.

10. A method according to the preceding claim wherein the capsule functionalization step includes the addition of at least one silica precursor.

11. A process according to the preceding claim wherein the silica precursor for functionalization represents a maximum of 10%, preferably 7% by weight of the total weight of the silica precursor used in step a), preferably the functionalization represents a weight less than or equal to 5% of the total weight of the silica precursor used in step a).

12. A process according to any one of the preceding claims wherein the condensation agent is added in step b) to be in an amount less than or equal to 100g / L in the matrix phase, preferably less than or equal to 50g / L, preferably less than or equal to 20g / L.

13. A process according to any one of the preceding claims wherein the silica precursor or a precursor mixture of step a) is selected from at least one of tetraethyl orthosilicate (TEOS), tetramethyl orthosilicate (TMOS), (3-Aminopropyl)triethoxysilane (APTES), sodium metasilicate, calcium silicate, trimethoxymethylsilane (MTMOS), triethoxymethylsilane (MTEOS), triethoxysilane, trimethoxysilane, triethoxy(ethyl)silane (ETEOS), trimethoxy(ethyl)silane (ETEOS), isobutyl(trimethoxy)silane, propyl(trimethoxy)silane, sodium orthosilicate.

14. A method according to any one of claims 1 to 12 wherein the silica precursor of step a) is chosen from at least one including a biogenic silica extract, sodium silicate, or a natural source of orthosilicic acid.

15. A process according to any one of the preceding claims wherein at least one silica precursor is added in step a) in an amount less than or equal to 6000mM, preferably at least one silica precursor is present in step c) in an amount less than or equal to 1000mM.

16. A method according to any one of the preceding claims wherein the monovalent, divalent or trivalent anion is added in a concentration less than or equal to 300mM.

17. A method according to any one of claims 1 to 16 wherein the mixture from step b) is added to the nuclei obtained in step a).

18. A method according to any one of the preceding claims comprising after step c) a step d) of separating the capsules by centrifugation or filtration or decantation and optionally a step e) of washing the isolated capsules and optionally a step f) of drying the capsules.

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