Composition for the cosmetic and/or pharmaceutical treatment of the upper layers of the epidermis by topical application to the skin, and corresponding preparation process

Abstract

Composition comprising biodegradable nanoparticles encapsulating oils which are active and/or which contain an active ingredient having a cosmetic and/or pharmaceutical action in the upper layers of the epidermis. The nanoparticles are preferably prepared from a polymer of (C 2 -C 12 ) alkyl cyanoacrylate.

1 . Composition for the cosmetic and/or pharmaceutical treatment of the upper layers of the epidermis, by topical application to the skin, characterised in that it comprises, in a suitable vehicle, biodegradable polymer nanoparticles encapsulating at least one active ingredient in the form of an oil and/or at least one active ingredient contained in an inactive carrier oil or an active oil, the active ingredient being selected from those having a cosmetic and/or pharmaceutical action.  
     
     
         2 . Composition according to    claim 1   , characterised in that the nanoparticles are between 10 and 1,000 nm in size.  
     
     
         3 . Composition according to one of claims  1  and  2 , characterised in that the weight of the nanoparticles loaded with at least one active ingredient constitutes from 0.1% to 20% of the total weight of the composition.  
     
     
         4 . Composition according to one of    claims 1    to    3   , characterised in that the polymer constituting the nanoparticles is selected from the group composed of polymers of (C 2 -C 12 ) alkyl cyanoacrylate, poly-L-lactides, poly-DL-lactides, polyglycolides, polycaprolactones, polymers of 3-hydroxybutyric acid, copoly(DL-lactides/glycolides) and copoly(glycolides/caprolactones).  
     
     
         5 . Composition according to    claim 4   , characterised in that the polymer constituting the nanoparticles is a (C 2 -C 6 ) alkyl cyanoacrylate.  
     
     
         6 . Composition according to    claim 5   , characterised in that the alkyl radical of the cyanoacrylate is selected from the group composed of ethyl, n-butyl, hexyl, isobutyl and isohexyl radicals.  
     
     
         7 . Composition according to one of    claims 1    to    6   , characterised in that the active ingredient in the form of an oil or the active oil is selected from the group composed of α-tocopherol, α-tocopherol acetate, triglycerides rich in linoleic and/or linolenic acid(s), pentaerythritol tetra(2-ethylhexanoate), clofibrate, tocopherol linoleate, fish oil, hazelnut oil, bisabolol, farnesol, farnesyl acetate, ethyl linoleate and ethylhexyl para-methoxycinnamate.  
     
     
         8 . Composition according to one of    claims 1    to    7   , characterised in that the inactive carrier oil is selected from the group composed of triglycerides, simple or modified by oxyethylenation, volatile silicone oils and mixtures thereof.  
     
     
         9 . Composition according to one of    claims 1    to    8   , characterised in that the active ingredient contained in an oil is selected from the group composed of emollients, humectants, free radical-inhibiting agents, anti-inflammatories, vitamins, depigmenting agents, anti-acne agents, antiseborrhoeics, keratolytics, slimming agents and skin colouring agents.  
     
     
         10 . Composition according to one of    claims 1    to    9   , characterised in that the weight ratio of the biodegradable polymer of the nanoparticles to the active oily phase is between 0.05 and 0.5.  
     
     
         11 . Composition according to one of    claims 1    to    10   , characterised in that it takes the form of a physiological fluid, a lotion, an aqueous, aqueous alcoholic or oily gel or a water-in-oil or oil-in-water emulsion, or alternatively of aqueous dispersions of vesicles in which the constituent lipids are ionic or nonionic lipids or a mixture of ionic and nonionic lipids, with or without an oily phase.  
     
     
         12 . Composition according to one of    claims 1    to    10   , characterised in that at least a part of its nanoparticles contains at least one lipid lamella around the polymer membrane of the nanoparticle.  
     
     
         13 . Process for preparing a composition according to one of    claims 1    to    12   , characterised in that, to obtain the nanoparticles of the composition, an interfacial polymerisation of a microemulsion of oil in an aqueous-alcoholic medium is performed by injecting, into an aqueous phase which can contain a surfactant, a mixture consisting of the oil(s) to be encapsulated, at least one (C 2 -C 12 ) alkyl cyanoacrylate and at least one solvent which can contain a surfactant, and then evaporating off the solvent.  
     
     
         14 . Process according to    claim 13   , in which the aqueous phase contains a surfactant, characterised in that the weight ratio of the surfactant used on the one hand, to the materials constituting the nanoparticles loaded with active ingredient(s) on the other hand, is between 0.01 and 0.5.  
     
     
         15 . Process for preparing a composition according to one of    claims 1    to    12   , characterised in that, to obtain the nanoparticles of the composition, a mixture containing the oil(s) to be encapsuated, at least one polymer and at least one solvent which can contain a surfactant is injected into an aqueous phase which can contain a surfactant, and the said solvent is then evaportated off.  
     
     
         16 . Process according to one of    claims 13    to    15   , characterised in that a surfactant taken from the group composed of nonionic surfactants, ionic surfactants and mixtures thereof is used.  
     
     
         17 . Process according to    claim 16   , characterised in that the nonionic surfactant is selected from the group composed of the condensates of glycerol, ethylene oxide and propylene oxide.  
     
     
         18 . Process according to    claim 16   , characterised in that a lecithin is selected as an ionic surfactant.