Porous particles loaded with cosmetically or pharmaceutically active compounds

Abstract

The present invention relates to individualized porous particles, characterized in that they have a volume-average diameter of less than or equal to 10 μm and a specific surface area of greater than or equal to 1 m2/g, and in that they comprise at least one cosmetically or pharmaceutically active compound at least present inside said particles.

Description

The present invention relates to individualized porous particles having a volume-average diameter of less than or equal to 10 μm and containing at least one cosmetically or pharmaceutically active compound, and to their use in particular for transporting and releasing said active compound in the pilosebaceous unit.

To increase the efficacy of formulations for topical application, whether they are cosmetic or pharmaceutical in type, a certain number of methods have already been proposed which aim to improve the penetration of the active molecules into the stratum comeum forming the superficial layer of the skin. By way of examples of these methods, mention will be made of those using, as vehicle for these active molecules, liposomes, nanocapsules, O/W emulsions, short alcohols, glycols, etc.

The pilosebaceous unit forms, within the stratum corneum, the epidermis and the dermis, an invagination comprising a hair follicle and a sebaceous gland. It is the site of considerable biological and enzymatic activity which has a major effect on the appearance of the skin. Among these effects, mention may be made, for example, of the influence of the production of the sebum on the greasy or dry nature of the skin, and the influence on the growth or on the loss of growth of the body hair or of the head hair on the pilosity of the skin. The pilosebaceous unit can also be the subject of an inflammatory process. Such a process can have various causes and can in particular be related to the presence of microorganisms. This process can result in or contribute to the manifestation of a certain number of skin conditions such as acne. In addition, the pilosebaceous unit constitutes a potential route of passage for agents intended to act on deep skin tissues, for example for agents of the deep antiwrinkle type, of the slimming type, etc.

The structure of this pilosebaceous unit, both by virtue of its morphology with the presence of a hair, and by virtue of its physiology with a continuous flow of sebum, naturally opposes the penetration and/or the diffusion of active compounds within and into the depths of this structure.

However, methods for targeting active compounds into the pilosebaceous unit have already been proposed.

Thus, Application EP 0 375 520 describes the use of microspheres of natural or synthetic polymers or of fatty substances with a melting point above 50° C., loaded at least with an active product, and in which at least 80% by weight of these microspheres are between 3 μm and 10 μm in diameter, for preferentially transporting the active product into the pilosebaceous unit. The microspheres described in that application are either microspheres consisting of crosslinked materials, or solid microspheres loaded by partial solubilization of their constitutive materials, and which have a specific surface area of less than 1 m²/g. In addition, the processes for preparing microspheres described in that document, which comprise the encapsulation of the active compound either by means of solvents having sufficient affinity with respect to the material making up the microsphere, or by the “emulsification-evaporation” method, only allow an approximate control of the homogeneity of the microspheres obtained and therefore result, besides their low capacity to load the active compound(s), in a variation of this capacity and also in a variation of their capacity to release the active compound(s) in the pilosebaceous unit.

Application WO 02/07674 proposes a method for increasing the penetration of an active compound into the pilosebaceous unit using a composition in the form of microspheres or of liposomes having the property of being introduced into the follicle and of swelling therein by virtue of subsequently being in contact with a swelling agent, so as to generate therein a passage into the follicle. However, WO 02/07674 does not provide any concrete example illustrating the method proposed and does not therefore make it possible to verify the effectiveness thereof.

U.S. Pat. No. 6,287,549 describes a method of hair removal using a composition comprising organic microparticles loaded with chromophore agents, in which at least 80% by weight of the microparticles used are between 3 and 10 μm in size, in order to transport the chromophore agent into the pilosebaceous unit. These microparticles may be of various types and may be loaded with chromophores either as they are formed, or by impregnation of already formed microcapsules. In these microparticles, the compounds transported are not active compounds as such, since they require the intervention of an outside factor in order to be able to exercise an effect. In addition, the exercising of this effect does not require their release from the microparticles. Moreover, that document, which explicitly provides for an optional step of application of a composition for solubilizing the chromophores so as to allow their release from the microparticles, does not suggest the possibility of a passive release and even illustrates the existence of a preconceived idea against this.

U.S. Pat. No. 4,690,825 describes vehicles consisting of porous particles which are between 10 μm and 100 μm in size, for the controlled release of active ingredients. These particles are prepared by copolymerization of monomers based on styrene or on vinyl stearate and on divinylbenzene, or on methyl methacrylate and on ethylene glycol dimethyl methacrylate, in the presence of a porogen which is also the active ingredient. There is therefore a risk that the product obtained will contain residues from the process for preparing it, which is likely to affect its innocuity.

Application WO 99/53904 describes soft capsules containing an oily suspension or a silicone/polyethylene glycol emulsion and spherical porous microparticles prepared in particular according to U.S. Pat. No. 4,690,825 mentioned above. More precisely, this application describes porous microparticles having a mean particle diameter by weight of 20 μm, loaded either with retinol or with ascorbic acid.

Finally, U.S. Pat. No. 6,387,995 describes a process for producing an adsorbent polymer in the form of agglomerated, i.e. non-individualized, microparticles with a very low mass by volume ranging from 0.02 g/cm³ to 0.1 g/cm³, capable of trapping lipophilic compounds. The amount of compound trapped in the particles is negligeable compared with that of the compound trapped in the space formed by the agglomerated particles.

It has now been discovered that it is possible to transport at least one active compound and to release it in the pilosebaceous unit with increased effectiveness compared to the embodiments discussed above. The means found also makes it possible to improve the encapsulation of the active compound, compared to the solutions proposed to date, while at the same time exhibiting a particularly satisfactory innocuity.

According to a first aspect, the present invention relates to individualized porous particles having a volume-average diameter of less than or equal to 10 μm and a specific surface area of greater than or equal to 1 m²/g, comprising at least one cosmetically or pharmaceutically active compound at least present inside said particles.

According to a second aspect, the present invention relates to a cosmetic or pharmaceutical composition comprising particles as defined above.

The expression “porous particles” denotes particles having a structure containing pores.

This structure may be of matricial type, like a sponge. It may also be of vesicular type, i.e. the particle has an internal cavity delimited by a porous wall.

The porosity associated with the size of the particles is characterized quantitatively by their specific surface area. The porous particles of the invention have a specific surface area, measured according to the BET method, of greater than or equal to 1 m²/g.

The expression “individualized particles” denotes particles which are not grouped together in the form of an aggregate or of an agglomerate. These particles have in particular a mass by volume of greater than or equal to 0.15 g/cm³, and in particular ranging from 0.2 to 5 g/cm³.

The expression “cosmetically or pharmaceutically active compound” is intended to mean, in the context of the present invention, a compound which, by itself, i.e. not requiring the involvement of an outside agent to activate it, has biological activity. In addition, this activity needs the compound to be in direct contact with its target.

The particles used according to the present invention derive from preformed porous particles, i.e. particles formed in the absence of the compound(s) to be encapsulated.

For the purpose of the present invention, the expression “loaded particles” will be used hereinafter to denote the particles according to the invention in such a way as to distinguish them from the particulate material from which they derive and which does not contain active compound.

The loaded particles according to the invention do not therefore substantially contain residues related to the process for producing the particles from which they derive, which of course constitutes an improvement in terms of innocuity compared to particles which, in order to load the active compound, must be formed in its presence. Moreover, they are not solid.

The particles of the invention are in particular characterized by a high specific surface area, measured by BET.

The BET (BRUNAUER-EMMET-TELLER) method is a method well known to those skilled in the art. It is in particular described in “The journal of the American Chemical Society”, vol. 60, page 309, February 1938, and corresponds to the international standard ISO 5794/1 (annexe D). The specific surface area measured according to the BET method corresponds to the total specific surface area, i.e. it includes the surface area formed by the pores.

According to a particular embodiment, the particles of the invention have a specific surface area, measured by BET, ranging especially from 2.5 to 1000 m²/g, in particular from 3 to 750 m²/g.

As mentioned above, the particles according to the present invention have a volume-average diameter of greater than or equal to 10 μm.

In fact, such particles can penetrate into the sebaceous follicle by application of a mechanical force. This mechanical force generally comes from a massage which, besides the pushing that it exerts, generates a pump effect in the follicle.

The particles thus gradually reach the follicle canal in which the active compound that they are carrying can then diffuse and, possibly, reach the tissues surrounding the follicle canal. On the other hand, the carrier, which constitutes the particle, is then discarded by virtue of the flow of sebum and/or the growth of the body hair, thus making it possible to avoid any adverse reaction by the organism with respect to the solid compound constituting the particles.

It should be noted that particles having a diameter of greater than 10 μm, even with application of a similar mechanical force, mostly remain located on the surface of the skin without penetrating therein, and can therefore release the active compound only on the cornified layer.

According to a particular embodiment of the invention, the particles have a volume-average diameter of greater than or equal to 0.1 μm, and in particular ranging from 0.5 to 8 μm.

According to a variant of the invention, the particles are characterized by virtue of their particle size homogeneity. In particular, they have a polydispersity index, PI, ranging from 1 to 4, and in particular less than or equal to 3. This polydispersity index is defined as the ratio D(4.3)/D(3.2), in which D(4.3) denotes the volume-average diameter and D(3.2) denotes the surface-average diameter. These two values are commonly measured using laser diffraction particle size measuring devices such as that sold under the name “Mastersizer 2000” by the company MALVERN.

The porous particles of the invention may have varied shapes, especially globular, and in particular substantially spherical.

The porous particles from which the loaded particles according to the invention derive generally consist of materials which are completely insensitive, especially in terms of solubilization and plasticization, to the process for encapsulating the active compounds, in particular when this involves an organic solvent for the impregnation.

These particles may be of organic, inorganic or mixed type and are most commonly provided in the form of a powder with, in particular, a low volatility.

As porous particles of organic type, mention will be made, by way of example, of particles of Nylon 6, Nylon 6-6, Nylon 12 or Nylon 6-12, such as those sold by the company ATOFINA under the generic name “Orgasol”, and particles of poly(methyl methacrylate) (PMMA) such as those sold under the name “Covabead®” by the company WAKER.

In a particular embodiment of the invention, the particles used are chosen from the nylon particles mentioned above.

As porous particles of inorganic type, mention will be made, by way of example, of particles consisting of silica such as those sold under the name “God Balls” by the company SUZUKI OIL AND FAT or those sold under the name “Sunsphere H series” by the company ASAHI GLASS, alumina-silica particles such as those sold under the name “Zeeosphere®” by the company 3M, hydroxyapatite particles such as those sold under the name “ASP®” by the company SEKISUI PLASTICS, or under the name “Hydroxyzomes” by the company ASAHI GLASS, titanium dioxide particles such as those sold by the company ISHIHARA, and particles made up of a mixture of these minerals.

In one embodiment of the invention, the particles used are in particular chosen from silica particles and hydroxyapatite particles.

The porous particles used in the present invention may also consist of organic and inorganic composite materials.

The loaded particles according to the present invention comprise at least one cosmetically or pharmaceutically active compound, said compound being at least present inside the said porous particles. The active compound can also be present at the surface of the loaded particles, but in such a case, it is generally present mostly inside said particles.

The ratio by weight of the active compound(s) to the porous particles not loaded with active compound(s) is generally from 1/1000 to 10/1, in particular from 1/100 to 1/1.

The active compounds may be hydrophilic or lipophilic. According to a particular variant of the invention, the loaded particles comprise at least one lipophilic active compound. They can also comprise at least one hydrophilic active compound, it being possible for the latter to be sufficiently solubilized by amphiphilic compounds present in the sebum to allow its release.

The active compounds considered hereinafter are, without distinction, hydrophilic or lipophilic.

Among the active compounds, mention may in particular be made of:

• • antibacterial agents such as triclosan, IPBC (iodo-3-propynyl-2-butyl carbamate), benzalkonium chloride, chlorhexidine, etc.,
  • antifungal agents such as piroctone olamine, zinc pyrithione, climbazole, rilopirox, ketoconazole, itraconazole, etc.,
  • sebum regulators such as the iminodibenzyl or fluorene derivatives as described in U.S. Pat. No. 6,355,687, the substituted secondary amine derivatives as described in U.S. Pat. No. 6,355,686, the glucuronic acid and glucosamine derivatives, and their salts, as described in Patent Application EP 1 219 296, or the combinations of niacinamides with a C₁₁-C₃₀ alkyl or alkenyl ester of salicylic acid as described in Patent Application WO 02/067889,
  • sebum stimulators such as DHEA and its synthetic or natural derivatives, α-hydroxylated derivatives of vitamin D1 such as those described in U.S. Pat. No. 6,369,099,
  • keratolytic agents such as salicylic acid and its derivatives, for instance more particularly 5-n-octanoylsalicylic acid, alpha-hydroxy acids such as those, for example, of glycolic acid, lactic acid or malic acid, and resorcinol,
  • agents for treating acne, such as retinol and its derivatives, retinoic acid and its all-trans or 13-cis isomers, benzoyl peroxide, the cytochrome P450 inhibitors as described in U.S. Pat. No. 6,399,774 and their derivatives, and azelaic acid,
  • antibiotics which may or may not have a macrolide structure, the avermectin compounds as described in U.S. Pat. No. 6,399,652, [(2,4,6-triisopropylphenyl)-acetyl]sulphamic acid 2,6-diisopropylphenyl ester or a salt thereof, as inhibitor of cholesteryl and wax ester synthesis, as described in Patent Application WO 01/56556,
  • hair loss inhibitors and also hair growth stimulators such as minoxidil, biotin, finasteride, 2,4 dipyrimidine N-oxide, panthenol and their derivatives, flavanone T, or more generally any plant extract, having anti-5-alpha-reductase type I or II activity,
  • agents which inhibit the growth of head hair or of body hair, such as the serine proteases described in U.S. Pat. No. 6,407,056, cafeic acid, quercetin, propyl gallate, nordihydroguaiaretic acid or NDGA, indomethacin, eflornithine hydrochloride, the plant extracts as described in U.S. Pat. No. 6,171,595, such as the extracts of clove, of rosehip, of burnet, of gambir, etc., the compounds described in U.S. Pat. No. 6,075,052, tetramisole, sodium orthovanadate, levamisole, disodium chromoglycate, vanadium nitrate and gallium nitrate as described in U.S. Pat. No. 6,020,006, and also the compounds described in Patents U.S. Pat. Nos. 4,885,289, 4,720,489, 5,132,293, 5,096,911, 5,095,007, 5,143,925, 5,328,686, 5,440,090, 5,364,885, 5,411,991, 5,648,394, 5,468,476, 5,475,763, 5,455,608, 5,674,477, 5,728,736 and 5,652,273 and in Patent Applications WO 94/27586, WO 94/27563 and WO 98/03149. Use may also be made of the extracts of juniper as described in U.S. Pat. No. 6,375,948,
  • anti-dandruff agents such as zinc pyrithione,
  • antioxidants such as butylhydroxytoluene (BHT), carotenoids such as β-carotene, lycopene, canthaxanthine, ubiquinone, dibutylpentaerythrityl tetrahydroxycinnamate, vitamin E, trolox, vitamin C and its derivatives,
  • astringents and pore-reducing agents, such as those described in Patent Application WO 02/32392,
  • antiperspirant agents such as aluminium salts and zirconium salts,
  • vitamins, other than those mentioned above, and such as vitamin B3, vitamin K, vitamin H, vitamin PP, vitamin D, vitamin B6 and their derivatives, and
  • anti-inflammatory agents such as α-bisabolol, dipotassium glycyrrhizinate, glycyrrhetinic acid and its derivatives, ellagic acid, ursolic acid, ibuprofen, naproxen, fenoprofen, carprofen, ketoprofen, steroidal anti-inflammatory agents such as cortisone, pregnenolone, desonide, and mixtures of alkolamines and of tyrosine, such as those described in Patent Application EP 1 192 939.

The loaded particles of the present invention are prepared according to conventional methods, in particular by impregnation.

In particular, the loaded particles according to the invention are obtained by impregnation of preformed porous particles with at least one active compound. Advantageously, this protocol does not require the presence of a porogen.

By way of example, the impregnation process consists in presolubilizing the compound(s) to be encapsulated in a solvent which is suitable and in an amount necessary and sufficient to impregnate the particles, and then in bringing this mixture into contact with porous particles in accordance with the invention. The solvent is then evaporated off until a dry powder is obtained. The powder thus obtained generally contains only a very small proportion of residual solvent, of the order of 1/10 ppm.

As solvents which may be used in such an impregnation process, mention may in particular be made of acetone, ethanol, isopropanol, dichloromethane, ethyl acetate, etc. Of course, the choice of solvent is made taking into account the nature of the components of the porous particles and of the compounds to be encapsulated.

When the compound to be encapsulated is in the form of a liquid, it may be brought directly into contact with the porous particles without the addition of a secondary solvent.

Those skilled in the art will take care to choose the impregnation conditions so as to obtain a dry powder.

The loaded particles of the invention allow specific administration of said cosmetically or pharmaceutically active compound(s) into the pilosebaceous unit.

These particles can be introduced in various cosmetic or pharmaceutical formulations intended for topical application.

The present invention therefore also relates to a cosmetic or pharmaceutical composition comprising loaded particles as defined above.

Of course, said composition may comprise only one type of particles as defined above, or else a mixture of such particles.

Generally, the composition contains from 0.1 to 50% by weight, and in particular from 0.2 to 20% by weight, of particles as defined above relative to the total weight of the composition.

The composition according to the invention may also comprise:

• • at least one cosmetically or pharmaceutically active compound intended to act essentially outside the pilosebaceous unit, and/or
  • at least one cosmetically or pharmaceutically acceptable additive, and/or
  • a galenic carrier, which may be of any suitable type.

The term “carrier” is intended to denote any mode of vehicle compatible with cosmetic or pharmaceutical use, namely of liquid type such as water, an aqueous-alcoholic solvent, oil, or a mixture thereof, or of solid type such as wax for example.

Care will, however, be taken to ensure that the optional additional cosmetically or pharmaceutically active compound, the optional additive and the optional carrier do not cause the release of the active compound in the composition.

According to a particular embodiment, the compositions of the invention are substantially free of surfactants.

The cosmetic or pharmaceutical composition may be provided in the form of lotions, O/W or W/O emulsions, or aqueous or aqueous-alcoholic gels, or alternatively in anhydrous form, such as sticks, sprays or compact or free powders.

The compositions of the invention may be care compositions, hygiene compositions or makeup compositions.

They may also be intended, for example, for use on the hair and may in particular be shampoos, conditioners, hair lotions, in particular for hair care.

They may also be makeup sticks such as lipsticks, or personal hygiene sticks such as deodorants.

Examples presented hereinafter are given by way of illustration and are not limiting in nature.

FIGURE

FIG. 1: Electron micrograph consisting of silica particles containing triclosan in accordance with the invention.

EXAMPLE 1

Two compositions containing a lipophilic active compound, 5-n-octanoylsalicylic acid, namely respectively a gel containing 4 μm porous particles of nylon (“Orgasol®”), which is the subject of the invention, and an O/W emulsion with the same mean particle size are compared in terms of pilosebaceous unit-targeting effectiveness. The amount of active principle, 5-n-octanoylsalicylic acid, is identical in the two types of composition, and is set at 0.3% by weight.

The Compounds Tested

Composition 1 (according to the invention)
Poly(ammonium acryloyldimethyltaurate) 0.50 g
Porous particles of Nylon-12*    4.70 g
5-n-octanoylsalicylic acid       0.30 g
Poloxamer 338                    0.25 g
Demineralized water              94.25 g
*The porous particles of Nylon-12 are sold under the name “Orgasol 2002 UD Nat cos” by the company ATOFINA.

Composition 2 (comparative O/W emulsion)
Xanthan gum                0.10 g
Glyceryl stearate          1.00 g
Sodium hydroxide           0.10 g
Cetyl alcohol              2.00 g
Octyldodecanol             9.00 g
Glycerol                   3.00 g
Hydrogenated polyisobutene 2.00 g
Water                      71.95 g
5-n-Octanoylsalicylic acid 0.30 g
Paraffin oil               5.00 g
Carbomer                   0.30 g
PEG-100 stearate           1.00 g
Polysorbate 60             4.00 g
Methylparaben              0.25 g

The study was carried out on eight volunteer individuals who have oily skin exhibiting dilated pores on the forehead.

For each individual, after having carefully cleaned the face with soap, 4 mg/cm² of the composition to be tested are applied to the left or right side half of the forehead, and the area treated is then massaged for 1 minute and left to dry for 15 minutes. This application is repeated for 4 days under the same conditions (i.e. a total treatment period of 5 days with a single daily application).

On day 6, an epidermal sample is taken from each individual by cyanoacrylate strip, applying onto the forehead of each individual a glass slide onto which a drop of cyanoacrylate has been deposited, and then, after drying, removing said slide, which thus entrains an epidermal sample.

The follicles and the comedones are then removed from said samples and their content is extracted in methanol. The amount of active compound is quantified by HPLC.

The results are presented in Table 1 below.

	TABLE 1
		5-n-Octanoylsalicylic acid
	Number of comedones	in pg per comedone
	Area	Area	Area	Area
Testers	composition 2	composition 1	composition 2	composition 1	Enrichment
1	29	34	439	656	50%
2	20	16	282	566	101%
3	25	27	121	200	66%
4	30	33	709	1288	82%
5	24	13	571	986	73%
6	29	19	468	836	79%
7	11	13	57	259	353%
8	28	25	144	433	201%

It is noted, according to the results set out above, that composition 1 according to the invention, which contains the porous particles loaded with 5-n-octanoylsalicylic acid, makes it possible to significantly increase the amount of 5-n-octanoylsalicylic acid in the follicle by a rate of at least 50%, compared with a composition in the form of an emulsion containing the same amount of 5-n-octanoylsalicylic acid.

This trial shows the effectiveness of the porous particles of the invention for transporting active molecules into the pilosebaceous unit.

EXAMPLE 2

Preparation of the Organic Particles Containing an Active Compound

Particle composition
Porous particles of Nylon-12, sold under the name “Orgasol 2002 7.5 g
UD Nat Cos” ® by the company ATOFINA
Triclosan                        2.5 g

2.5 g of triclosan are solubilized in 50 ml of acetone. 7.5 g of “Orgasol®” are introduced into this mixture. The dispersion is then introduced into a rotary evaporator in order to eliminate the acetone. A powder loaded with triclosan is then obtained.

The powder thus obtained can then be redispersed in water, in a gel or in an emulsion. Care will be taken to ensure that the composition into which the particles containing the triclosan are introduced does not promote leaking of said triclosan into the galenic carrier.

EXAMPLE 3

Preparation of Organic Particles Containing an Active Compound

Particle composition
Porous particles of silica sold under the name “God Balls2 7.5 g
EC ®” by the company SUZUKI OILS & FATS
Vitamin E                        1.5 g
5-n-Octanoylsalicylic acid       1.0 g

1.5 g of vitamin E and 1 g of 5-n-octanoylsalicylic acid are solubilized in 50 ml of acetone. 7.5 g of “God Balls 2 EC®” porous particles are introduced into this mixture. The dispersion is then introduced into a rotary evaporator in order to eliminate the acetone. A powder loaded with vitamin E and with 5-n-octanoylsalicylic acid is then obtained.

The powder thus obtained can then be redispersed in water, in a gel or in an emulsion. Care will, however, be taken to ensure that the composition into which the particles containing the vitamin E and the 5-n-octanoylsalicylic acid are introduced does not promote leaking of these active agents into the galenic carrier.

Similarly, a powder of particles was prepared with 7.5 g of “God Balls 2 EC®” porous particles and 2.5 g of triclosan. The powder is observed under an electron microscope. A micrograph thereof is shown in FIG. 1.

It is noted that the powder thus obtained consists of individualized particles.

EXAMPLE 4

Anti-Acne Cream (Oil/Water Emulsion)

Poly(ammonium acryloyldimethyltaurate) 0.40 g
Xanthan gum                      0.20 g
Preserving agents                0.80 g
Disodium EDTA                    0.05 g
Glycerol                         5.00 g
Demineralized water              75.04 g
Porous particles according to Example 2 3.00 g
Mixture of cetearyl alcohol/dimyristyl tartrate/C12-15 Pareth- 1.50 g
7/PPG-25-Laureth-25
Stearyl alcohol                  1.00 g
Mixture of glyceryl stearate/PEG-100 stearate 2.00 g
Cyclohexasiloxane                10.00 g
Ethylhexyl methoxycinnamate      1.00 g
Fragrance                        0.01 g

This smooth and fresh cream makes it possible to combat problems of acne with good effectiveness.

EXAMPLE 5

Tonic Lotion

Butylene glycol                  1.00 g
Zinc oxide                       0.50 g
Lactic acid                      0.10 g
Glycerol                         1.00 g
Propylene glycol                 0.20 g
PEG-60 hydrogenated castor oil   0.15 g
Ethanol                          5.00 g
30 nm colloidal silica           0.50 g
Porous particles according to Example 2 1.00 g
Demineralized water              90.33 g
Extract of Hamamelis virginiana  0.0002 g
Menthoxypropanediol              0.01 g
Methylparaben                    0.20 g
Fragrance                        0.01 g

EXAMPLE 6

W/O Emulsion

Phase A:
Isohexadecane                    8.00 g
Squalane                         3.70 g
Polydimethylsiloxane (viscosity: 10 cst) 4.10 g
Apricot kernel oils              2.30 g
Lubrizol 5603                    1.90 g
Phase B:
Ascorbic acid                    2.00 g
50% potassium hydroxide          1.20 g
Demineralized water              67.80 g
Glycerol                         5.00 g
Preserving agents                1.00 g
Phase C:
Particles according to Example 2 3.00 g

Phase B is emulsified slowly, at ambient temperature, in phase A, and then phase C is added.

Claims

1. Individualized porous particles, characterized in that they have a volume-average diameter of less than or equal to 10 μm and a specific surface area of greater than or equal to 1 m2/g, and in that they comprise at least one cosmetically or pharmaceutically active compound at least present inside said particles.

2. Particles according to claim 1, characterized in that they have a specific surface area ranging from 2.5 to 1000 m2/g, and in particular from 3 to 750 m2/g.

3. Particles according to either one of the preceding claims, characterized in that they have a mass by volume of greater than or equal to 0.15 g/cm3, and in particular ranging from 0.2 to 5 g/cm3.

4. Particles according to any one of the preceding claims, characterized in that they have a volume-average diameter of greater than or equal to 0.1 μm, and in particular ranging from 0.5 to 8 μm.

5. Particles according to any one of the preceding claims, characterized in that they have a polydispersity index ranging from 1 to 4, and in particular less than or equal to 3.

6. Particles according to any one of the preceding claims, characterized in that they are provided in the form of a powder.

7. Particles according to any one of the preceding claims, characterized in that they derive from organic porous particles.

8. Particles according to claim 7, characterized in that said organic porous particles are chosen from particles of Nylon 6, Nylon 6-6, Nylon 12 and Nylon 6-12 and particles of poly(methyl methacrylate).

9. Particles according to any one of claims 1 to 6, characterized in that they derive from inorganic porous particles.

10. Particles according to claim 9, characterized in that said inorganic porous particles are chosen from particles of silica, of alumina-silica, of hydroxyapatite, of titanium dioxide or of mixtures thereof.

11. Particles according to any one of the preceding claims, characterized in that they derive from porous particles made of an organic and inorganic composite material.

12. Particles according to any one of the preceding claims, characterized in that the ratio by weight of the active compound(s) to the porous particles not loaded with active compound(s) is from 1/1000 to 10/1, and in particular from 1/100 to 1/1.

13. Particles according to any one of the preceding claims, characterized in that they comprise at least one cosmetically or pharmaceutically active compound chosen from antibacterial agents, antifungal agents, sebum regulators, sebum stimulators, keratolytic agents, agents for treating acne, antibiotics, hair loss inhibitors/hair growth stimulators, agents which inhibit the growth of head hair or of body hair, anti-dandruff agents, antioxidants, astringents, pore-reducing agents, antiperspirant agents, vitamins, anti-inflammatory agents, and mixtures thereof.

14. Cosmetic or pharmaceutical composition, characterized in that it comprises particles as defined in any one of claims 1 to 13.

15. Cosmetic or pharmaceutical composition according to claim 14, characterized in that the proportion by weight of said particles relative to the total weight of said composition is from 0.1 to 50%, and in particular from 0.2 to 20%.

16. Cosmetic or pharmaceutical composition according to either one of claims 14 and 15, characterized in that it is provided in the form of a lotion, an O/W emulsion, a W/O emulsion, or an aqueous or aqueous-alcoholic gel, or in anhydrous form, such as a stick, a spray or a compact or free powder.