WO2008037697A1

WO2008037697A1 - Novel organogel particles, method for the preparation thereof and cosmetic uses thereof

Info

Publication number: WO2008037697A1
Application number: PCT/EP2007/060126
Authority: WO
Inventors: Plamen Kirilov; Sophie Franceschi-Messant; Isabelle Rico-Lattes; Emile Perez; Pascal Bordat
Original assignee: Pierre Fabre Dermo-Cosmetique; Centre National De La Recherche Scientifique (Cnrs); Universite Paul Sabatier Toulouse Iii
Priority date: 2006-09-25
Filing date: 2007-09-24
Publication date: 2008-04-03
Also published as: FR2906134A1; EP2066284A1

Abstract

The present invention relates to nanospheres of organogel comprising a low-molecular-weight organogelling agent capable of gelling a cosmetic or pharmaceutical active ingredient which is lipophilic or amphiphilic, non-volatile and liquid at ambient temperature. The low-molecular-weight organogelling agent is in particular 12-hydroxystearic acid. The invention also relates to a method for preparing aqueous dispersions of organogel nanospheres comprising, in particular, a step of hot emulsification or micro emulsification of an organogel, followed by cooling to ambient temperature. The invention also relates to the nanospheres and the aqueous dispersions of nanospheres obtained by the method according to the invention, and to the cosmetic or pharmaceutical compositions comprising them.

Description

NOVEL ORGANOGEL PARTICLES, PROCESS FOR THEIR PREPARATION, AND USES THEREOF IN COSMETICS

The present invention relates to new organogel particles, their process of preparation, and their uses, in particular in cosmetics.

Gels, widely used in cosmetics and in the food or petroleum industry, are generally diluted solutions of polymers, proteins, inorganic substances such as silica or clays in water or body fluids. Gelling agents are necessary for the formation and maintenance of these gels.

Recently, there has been a growing interest in low molecular weight organogelifiers. This situation is motivated not only by the many potential applications of the organogels obtained from these particular gelling agents, but also by the fact that these systems have interesting self-assembly properties. In these organogels, as for other gelled systems, the gelling agent forms a three-dimensional continuous network that immobilizes the liquid and prevents it from flowing. In contrast to their polymeric or inorganic analogues, the architecture of the network results from the self-assembly of low molecular weight organogelifiers by non-covalent forces, such as π-π interactions, hydrogen bonds, Van Der Walls forces. or else donor-acceptor interactions. Generally, the three-dimensional network consists of an assembly of organo-fibrillating molecules into fibrils, and these fibrils self-assemble into fibers and intersecting fiber bundles.

In the cosmetic, pharmaceutical or food fields, the organogels have the advantage of being able to contain active ingredients or ingredients to facilitate the introduction and the stability of said ingredients or active ingredients in compositions.

More particularly in the cosmetic field, several solutions have been envisaged to introduce, protect, and even vectorize certain ingredients when their stability could be questioned by the formulation medium, the manufacturing process, or when it is preferable that the active ingredient be released only a given place. The penetration of the active ingredients through the different layers of the skin can also be improved.

Many contemplated systems involve the incorporation or encapsulation of the active ingredient in particles of varying sizes and constitution depending on the nature of the active ingredient and the purpose of its use.

The Applicant has shown that it is possible to obtain new spherical particles from low molecular weight organogelling components. These particles will be designated throughout the patent application by the term nanospheres.

In the field of the encapsulation of active principles, these nanoparticles of organogels may have many advantages over liposome solutions or nanocapsule dispersions.

Firstly they have a better rate of encapsulation of lipophilic or amphiphilic active ingredients with a homogeneous distribution within the particles. The originality of these organogel nanoparticles is also due to the fact that the liquid active principle can be directly gelled and thus be the main component whose consistency can easily be modulated by varying the proportion of organogelling agent. Finally, the possible incorporation of a stabilizing agent (polymer or surfactant) on the surface of the organogel nanoparticles may allow easy functionalization for better vectorization.

The present invention therefore relates to organogel nanospheres comprising a low molecular weight organogelling agent capable of gelling a cosmetic or pharmaceutical active ingredient, lipophilic or amphiphilic, nonvolatile and liquid at room temperature.

The nanospheres according to the present invention are of nanometric size, and more particularly have a diameter of between 50 and 5000 nm, and preferably between 100 and 5000 nm.

Advantageously, the nanospheres according to the present invention are of substantially spherical, uniform shape, preferably with a smooth surface. By "substantially spherical" in the sense of the present invention means a shape very close to the sphere. More particularly, "substantially spherical" means that when a cross section is made, the difference found between the larger average diameter and the smallest average diameter is less than 20% and better still less than 10%.

The nanospheres of the invention may have a consistency ranging from a highly viscous liquid to a compact solid and this depending on the proportion of organogelling.

In an advantageous aspect, the proportion of the organogelling agent is between 0.1% and 50% by weight relative to the total weight of the organogelling agent and the cosmetic or pharmaceutical active ingredient.

According to the invention, the low molecular weight organogelling agent corresponds to a small organic molecule capable of gelling a wide range of organic liquids in small proportions. By low molecular weight in the sense of the present invention means a molecular weight of less than 1000 g / mol, and more particularly less than 500 g / mol.

In an advantageous aspect of the invention, the organogelling agent will be chosen from fatty acid esters, fatty acids and their monovalent, divalent or trivalent metal derivatives or derivatives, steroids and their derivatives, polyaromatic derivatives, macrocycles, sugar derivatives, fluorinated compounds, fatty amines, long-chain alkanes, long-chain ammonium carbamates, cholesterol and its derivatives, amides, bis-ureas, and mixtures of these derivatives.

For the purposes of the present invention, long-chain alkanes or long-chain ammonium carbamates are understood to mean compounds as designated which have a carbon chain containing between 8 and 36 carbon atoms. As the long chain alkane hexatriacontane may be mentioned.

Among the amides that can be used for the implementation of the present invention, preference will be given to alkylglutamides, N-hydroxyalkylamides, alkylidenediamides, peptides and polypeptides.

According to the present invention, the organogelling agent is preferably chosen from optionally substituted fatty acid derivatives as well as their monovalent metal salts, or their esters.

An organogelling agent particularly suitable for the implementation of the present invention is 12-hydroxystearic acid. In the context of the present invention, the cosmetic or pharmaceutical active ingredient (s) that can be gelled are liquid at ambient temperature, that is to say at 25 ° C. They have a lipophilic or amphiphilic character, preferentially lipophilic. Thus, and in a non-exhaustive manner, mention may be made of vegetable oils, mineral oils, emollient oils, silicone oils, fluorinated oils, essential oils, sunscreens, as well as any ingredient or active ingredient which is non-volatile and liquid to ambient temperature and atmospheric pressure, as well as all combinations of these organic liquids.

According to the invention, the maintenance of the particle is related to the formation of a three-dimensional network consisting of an assembly of organogelling molecules into fibrils which self-assemble fibers and intersecting fiber bundles that immobilize the organic liquid. within the particle. Stabilization is thus ensured. However, in the context of the implementation of the present invention, the nanospheres may further comprise at least one dispersing agent and stabilizer. In particular, this or these dispersing agents and stabilizers are incorporated in all or part of the surface of the nanospheres.

The dispersing agent and stabilizer will advantageously be selected from surfactants, cosurfactants, polymers, mineral particles and all combinations of these agents.

Among the surfactants, mention may be made of fluorinated or hydrogenated nonionic, cationic, anionic and zwitterionic amphiphilic molecules, for example sodium cholate, sodium deoxycholate, sodium glycocholate, sodium taurocholate, sodium taurodeoxycholate, Lecithins, phospholipids, Tween 20, Tween 40, Tween 60, Tween 80, Span 20, Span 40, Span 60, Span 80, sodium dodecyl sulphate, hexadecyltrimethylammonium bromide and all combinations thereof molecules.

Among the cosurfactants include bile acid salts such as sodium taurocholate, alcohols and glycols of low molecular weight such as butanol, hexanediol, propylene glycol and hexanol, amines or ketones short chain, low molecular weight acids such as butyric acid and caproic acid, esters of phosphoric acid, benzyl alcohol, butyl lactate, and all combinations of these molecules.

The polymers that are well suited to the practice of the present invention may be chosen from macromolecules of natural or synthetic origin, homopolymers or copolymers, filled homopolymers or charged copolymers, amphiphilic homopolymers or amphiphilic copolymers, hyperbranched polymers or copolymers, dendrimers, polysaccharides as well as all combinations of these macromolecules, emulsifiers such as gelatin, as well as all combinations of these polymers.

Among the mineral particles used for the implementation of the invention, there may be mentioned silicas, clays, aluminas, talc, metal oxides and all combinations of these particles.

Another major advantage of the nanospheres of the present invention is the distribution of the cosmetic or pharmaceutical active ingredient and the organogelling agent homogeneously within said nanospheres, from the center of the particles to the periphery.

The present invention also relates to a process for the preparation of aqueous dispersions of organogel nanospheres comprising the steps of:

(a) forming an organogel by mixing a low molecular weight organogelling agent with a cosmetic or pharmaceutical active ingredient, lipophilic or amphiphilic, nonvolatile and liquid at room temperature,

(b) adding to the organogel thus obtained water or an aqueous solvent immiscible with said organogel,

(c) emulsification or microemulsification of the mixture thus obtained at a temperature above the liquid-gel transition temperature of the organogel,

(d) cooling at room temperature the emulsion or microemulsion thus formed to give a suspension of organogel nanospheres.

The organogel is thus prepared by heating the gelling agent with a cosmetic or liquid pharmaceutical active ingredient until a liquid solution ("sol") is obtained. When the solution is cooled, a gel is formed from a certain temperature which freezes the organic liquid. This temperature corresponds to the transition temperature sol-gel (Tgel) which is a physical characteristic of the organogelling / liquid active ingredient pair.

After addition of the solvent, the emulsification or microemulsification step is preferably carried out in water with vigorous stirring or sonication. Depending on the nature of the nanospheres that are to be obtained, this emulsification or microemulsification step is optionally carried out in the presence of at least one dispersing and stabilizing agent, in particular chosen from those defined above. In this case, they will be present in the water or the immiscible aqueous solvent added in step b).

In an advantageous aspect of the invention, step a) is carried out at a temperature of between 30 and 150 ^° C.

Another advantageous aspect of the invention relates to a process as defined above, characterized in that the proportion of organogelling agent in step a) is between 0.1% and 50% by weight relative to the total weight of the organogelling agent and the cosmetic or pharmaceutical active ingredient.

In a particularly advantageous embodiment of the invention, the process for preparing the aqueous dispersions of organogel nanospheres is carried out as follows.

An aqueous solution of a surfactant or a polymer of 0.025 to 10% by weight, as dispersing agent and stabilizer, is poured on the liquefied organogel to reach a mass proportion of organic liquid of 1% to 50%, and preferably 20%. The mixture is stirred while hot at a temperature above T gel by "ultraturax" or sonication, preferably by sonication, over a period of 5 to 20 minutes, preferably 10 minutes, in steps of 5 minutes. Once the emulsion or microemulsion has been carried out, the mixture is cooled to ambient temperature (close to 25 ^° C., T <T gel). According to preferential implementations of the process, the surfactants, the cosurfactant or the polymers are chosen as follows: the surfactants are cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulphate (SDS) or polyoxyethylene (20) sorbitan monooleate ( Tween 80). the cosurfactant is sodium taurocholate the polymers are polyvinyl alcohol (PVA) hydrolyzed to 80%, average molecular weight M _w = 10,000 or hydroxypropylmethyl cellulose.

The invention also relates to aqueous dispersions of nanospheres that can be obtained according to the method described above.

These dispersions have the advantage of having a better stability than the corresponding emulsions which are in the form of oil droplets without organogelling agent. The organogelling content (HSA), the viscosity of the organic liquid to be gelled and the type of stabilizer used (surfactant or polymer) play a vital role in the stabilization process and makes it possible to obtain stable dispersions over several months. The synergy between the gelation and the viscosity of the oil in the development of a dispersion of nanospheres also determines the choice of the stabilizer. An ionic surfactant will be preferred for stabilizing dispersions of semi-solid particles made from a low viscosity oil. On the other hand, for highly viscous systems with a high content of organogelling agent, the nanospheres become very rigid and close to a solid, and in this case their steric stabilization with a polymer will be preferred.

In particular, the aqueous dispersions of nanospheres obtained according to the invention exhibit non-Newtonian behavior. The apparent viscosity of these systems varies non-linearly, it decreases with the increase in the shear rate, which corresponds to the rheofluidizing or pseudoplastic behavior characteristic of very concentrated emulsions or dispersions. This rheological behavior can be very interesting in the case of the spreading of a cosmetic cream.

The aqueous dispersions of nanospheres according to the invention are in particular characterized by modulus values of elasticity G 'of between 10 Pa and 10,000 Pa, and viscosity modulus values G' of between 10 Pa and 1000 Pa.

The rheological behavior of the aqueous dispersions of corresponding nanospheres is studied by following the viscoelastic modules G 'and G "and the tangent γ as a function of the shear frequency in the linear viscoelastic domain (determined by scanning the shear stress). results obtained it can be concluded that the viscosity of the constituent oil, as well as the in HSA strongly increase the elasticity of the aqueous dispersions of organogel nanospheres. This results in the existence of strong interactions between nanospheres, hence a rheological behavior characteristic of gels or solid materials of cosmetological interest.

In another aspect of the invention, the nanosphere preparation process further comprises a final lyophilization step to isolate them from the aqueous medium.

Thus, advantageously, the present invention also relates to the nanospheres that can be obtained according to the process above.

The nanospheres according to the present invention are intended to be used for the preparation of compositions whose utility depends on the nature of the active principle contained in said nanospheres. In another aspect, the present invention therefore relates to cosmetic or pharmaceutical compositions comprising the nanospheres or aqueous dispersions of nanospheres as defined above, and a physiologically acceptable excipient. Preferably, the amount of nanospheres varies from 5% to 50% by weight relative to the total mass of the composition.

The following examples serve to illustrate the invention, but do not limit it in any way. Example A

Preparation of the organogel: the gel is prepared from a 3% by weight solution of 12-hydroxystearic acid (HSA), ie 0.15 g in 5 g of dicapryl carbonate. In order to completely dissolve the HSA in the oil, the mixture is homogenized at a temperature of 75 ° C under ultrasound before being cooled to room temperature to form a compact and translucent gel.

Hot dispersion without stabilizer: 20g of water are added to the organogel thus obtained.

The mixture is heated at 75 ° C (T °> T ° gel) in an oven for 20 minutes. The liquefied organogel rises to the surface forming an oily layer (20% by mass). The mixture is then dispersed while hot (75 ° C.) by sonication (20kHz, 600W), twice 5 minutes.

Cooling at room temperature: the dispersion thus formed is cooled to room temperature to form organogel nanospheres. Size and size distribution: the gelosomes have a mean diameter of 3000 nm and a polydispersity index of 0.8 (light scattering).

Example B:

Preparation of the organogel: the gel is prepared from a 3% by weight solution of HSA, ie 0.15 g in 5 g of dicapryl carbonate. In order to completely dissolve the HSA in the oil, the mixture is homogenized at a temperature of 75 ° C under ultrasound before being cooled to room temperature to form a compact and translucent gel.

Hot Emulsification: to the organogel thus obtained are added 20g of a 2% by weight aqueous solution of cetyltrimethylammonium bromide (CTAB). The mixture is heated at 75 ° C (T> Tgel) in an oven for 20 minutes. The liquefied organogel rises to the surface forming an oily layer (20% by mass). The mixture is then emulsified while hot (75 ° C.) by sonication (20kHz, 600W), twice 5 minutes.

Cooling at room temperature: the emulsion thus formed is left at room temperature to form a stable dispersion of gelosomes.

Size and size distribution: the gelosomes have an average diameter of 300 nm and a polydispersity index of 0.15 (light scattering).

Example C

Hot emulsification: to the organogel thus obtained are added 20 g of a 2% by weight aqueous solution of polyoxyethylene (20) sorbitan monooleate (Tween 80) .The mixture is heated at 75 ° C. (T> T gel) to oven for 20 minutes. The liquefied organogel rises to the surface forming an oily layer (20% by mass). The The mixture is then emulsified while hot (75 ° C.) by sonication (20kHz, 600W), twice 5 minutes.

Size and size distribution: the gelosomes have an average diameter of 360 nm and a polydispersity index of 0.22 (light scattering).

Example D:

Preparation of the organogel: the gel is obtained by dissolving 0.15 g of HSA (3% by mass) in 5 g of isopropyl myristate. The solution is homogenized hot (T = 75 ° C) under ultrasound in order to completely dissolve the HSA in the oil. After cooling to room temperature, a compact and translucent gel is formed.

Preparation of the aqueous phase: the aqueous phase is prepared by dissolving 3% by weight of deoiled soy lecithin. The solution is then homogenized hot (75 ° C) by sonication (2OkHz, 600W), 2 times 10 minutes.

Hot Emulsification: to the organogel thus obtained are added 20 g of the 3% aqueous solution of soy lecithin. The mixture is heated at 75 ^° C. (T> T gel) in an oven for 20 minutes. The liquefied organogel rises to the surface forming an oily layer (20% by mass). The mixture is then emulsified while hot (75 ° C.) by sonication (20kHz, 600W), twice 5 minutes.

Size and size distribution: the gelosomes have a mean diameter of 100 nm and a polydispersity index of 0.15 (light scattering).

Example E:

Preparation of the organogel: the gel is prepared from a 3% by weight solution of HSA, ie 0.15 g in 5 g of isopropyl myristate. In order to completely dissolve the HSA in the oil, the mixture is homogenized while hot (T = 75 ° C.) under ultrasound before being cooled to ambient temperature to form a compact and translucent gel. Hot microemulsification: the organogel thus obtained is supplemented with 20 g of an aqueous solution containing 12% by weight of sodium taurocholate (co-surfactant) and 2% by weight of Tween 80 (surfactant). The mixture is heated at 75 ° C (T> Tgel) in an oven for 20 minutes. The liquefied organogel rises to the surface forming an oily layer (20% by mass). The mixture is then hot-micemulsified (75 ° C.) by sonication (20kHz, 600W), twice 5 minutes.

Cooling at room temperature: the microemulsion thus formed is left at room temperature to form a stable dispersion of gelosomes.

Size and Size Distribution: The resulting gelosomes have an average diameter of 200 nm and a polydispersity index of 0.3 (light scattering).

Example F

Preparation of the oil: a mixture of UVB + UVA solar filters is prepared by dissolving butylmethoxydibenzoylmethane (17% by mass) in hot (60 ^° C.) in octylmethoxycinnamate (UVB). The mixture thus obtained is then cooled to room temperature.

Preparation of the organogel: the gel is prepared from a 6% by weight solution of HSA, ie 0.3 g in 5 g of sunscreen. In order to completely dissolve the HSA in the oil, the mixture is homogenized while hot (T = 75 ° C.) under ultrasound before being cooled to ambient temperature to form a compact and slightly diffusing gel.

Hot Emulsification: to the organogel thus obtained are added 20 g of a 2% by weight aqueous solution of PVA hydrolyzed to 80%. The mixture is heated at 75 ° C (T> Tgel) in an oven for 20 minutes. The liquefied organogel rises to the surface forming an oily layer (20% by mass). The mixture is then heat-emulsified (75 ° C.) by sonication (20 kHz, 600W), twice 5 minutes.

Dehydration by lyophilization: the gelosomes are dehydrated by lyophilization for 24 hours. These can then be dispersed by simple agitation. Size and Size Distribution: The resulting gelosomes have an average diameter of 1000 nm and a polydispersity index of 0.5 (light scattering).

Example G:

Hot Emulsification: to the organogel thus obtained are added 20 g of a 2% by weight aqueous solution of hydroxypropylmethyl cellulose. The mixture is heated at 75 ° C (T> Tgel) in an oven for 20 minutes. The liquefied organogel rises to the surface forming an oily layer (20% by mass). The mixture is then emulsified while hot (75 ° C.) by sonication (20 kHz, 600W), twice 5 minutes.

Dehydration by lyophilization: the gelosomes are dehydrated by lyophilization for 24 hours. The latter can then be dispersed in water by simple agitation.

Size and Size Distribution: The resulting gelosomes have an average diameter of 750 nm and a polydispersity index of 0.35 (light scattering).

Example H:

Preparation of the organogel: the gel is prepared from a 3% by weight solution of dibenzylidene sorbitol (DBS), ie 0.13 g in 4.33 g of toluene. In order to completely dissolve the DBS in the oil, the mixture is homogenized while hot (T = 60 ° C.) under ultrasound to form a compact and opaque gel. Hot Emulsification: To the organogel thus obtained are added 20 g of a 2% by weight aqueous solution of cetyltrimethylammonium bromide (CTAB). The mixture is heated at 75 ° C (T> Tgel) in an oven for 20 minutes. The liquefied organogel rises to the surface forming an oily layer (20% by mass). The mixture is then heat-emulsified (75 ° C.) by sonication (20kHz, 600W), twice 5 minutes.

Cooling at room temperature: the emulsion thus formed is left at room temperature to form organogel nanoparticles.

Size and size distribution: the gelosomes have a mean diameter of 900 nm and a polydispersity index of 0.8 (light scattering).

Example I:

Preparation of the organogel: the gel is prepared from a solution containing 3% by weight of DBS, ie 0.13 g in 4.33 g of toluene. In order to completely dissolve the DBS in the oil, the mixture is homogenized while hot (T = 60 ° C.) under ultrasound to form a compact and opaque gel.

Hot Emulsification: To the organogel thus obtained are added 20 g of a 2% by weight aqueous solution of sodium dodecyl sulphate (SDS). The mixture is heated at 75 ° C (T> Tgel) in an oven for 20 minutes. The liquefied organogel rises to the surface forming an oily layer (20% by mass). The mixture is then heat-emulsified (75 ° C.) by sonication (20kHz, 600W), twice 5 minutes.

Size and size distribution: the gelosomes have a mean diameter of 400 nm and a polydispersity index of 0.7 (light scattering).

Claims

1. Organogel nanospheres comprising a low molecular weight organogelling agent capable of gelling a cosmetic or pharmaceutical active ingredient, lipophilic or amphiphilic, nonvolatile and liquid at room temperature.

2. Nanospheres according to claim 1, characterized in that they are substantially spherical and their diameter is between 50 and 5000 nm.

3. Nanospheres according to one of claims 1 or 2, characterized in that the organogelling agent has a molecular weight of less than 1000 g / mol.

4. Nanospheres according to one of claims 1 to 3, characterized in that the proportion of organogélifïant is between 0.1% and 50% by weight relative to the total weight of the organogélifïant and the active ingredient cosmetic or pharmaceutical.

Nanospheres according to one of claims 1 to 4, characterized in that the low molecular weight organogelling agent is chosen from fatty acid esters, fatty acids and their monovalent, divalent or trivalent metal derivatives or salts, steroids and their derivatives, polyaromatic derivatives, macrocycles, sugar derivatives, fluorinated compounds, fatty amines, long-chain alkanes, long-chain ammonium carbamates, cholesterol and its derivatives, amides, bis-ureas, and mixtures of these derivatives.

6. Nanospheres according to one of claims 1 to 5, characterized in that the organogelling agent is 12-hydroxystearic acid.

7. Nanospheres according to one of claims 1 to 6, characterized in that the active ingredient cosmetic or pharmaceutical, lipophilic or amphiphilic, nonvolatile and liquid at room temperature is selected from vegetable oils, oils and the like. mineral oils, emollient oils, silicone oils, fluorinated oils, essential oils, sunscreens, and mixtures thereof.

8. Nanospheres according to one of claims 1 to 7, characterized in that they further comprise at least one dispersing agent and stabilizer.

9. Nanospheres according to claim 8, characterized in that the dispersing agent and stabilizer is selected from surfactants, cosurfactants, polymers, mineral particles and combinations thereof.

10. Nanospheres according to one of claims 7 or 8, characterized in that the dispersing agent and stabilizer is incorporated in all or part of the surface of the nanospheres.

11. Nanospheres according to one of claims 1 to 10, characterized in that the cosmetic or pharmaceutical active ingredient and the organogelling agent are distributed homogeneously within said nanospheres, from the center of the particles to the periphery.

A process for preparing aqueous dispersions of organogel nanospheres comprising:

13. Preparation process according to claim 12, characterized in that the emulsification or microemulsification step is carried out in water with vigorous stirring or by sonication.

14. A method of preparation according to one of claims 12 or 13, characterized in that the emulsification or microemulsification step is carried out in the presence of at least one dispersing agent and stabilizer.

15. Preparation process according to claim 12, characterized in that step a) is carried out at a temperature between 30 and 150 ^° C.

16. Preparation process according to one of claims 12 to 15, characterized in that the proportion of the organogelling agent in step a) is between 0.1% and 50% by weight relative to the total weight of the organogelling agent and the cosmetic or pharmaceutical active ingredient.

17. Aqueous dispersions of organogel nanospheres obtainable by a process according to any one of claims 12 to 16.

18. Aqueous dispersions of nanospheres according to claim 17, characterized in that they are obtained in a form having an apparent viscosity that varies non-linearly.

19. Aqueous dispersions of nanospheres according to claim 17, characterized in that they have elastic modulus values G 'between 10 Pa and 10,000 Pa, and viscosity modulus values G ". between 10 Pa and 1000 Pa.

20. Preparation process according to one of claims 12 to 16, characterized in that it further comprises a final lyophilization step for isolating the nanospheres of the aqueous medium.

21. Nanospheres obtainable by the process according to claim 20.

22. Cosmetic or pharmaceutical composition comprising the nanospheres according to one of claims 1 to 11 or an aqueous dispersion of nanospheres according to one of claims 17 to 19, and a physiologically acceptable excipient.

23. Composition according to claim 22, characterized in that the amount of nanospheres varies from 5% to 50% by weight relative to the total mass of the composition.