Microcapsules comprising active ingredients and a metal oxide shell, a method for their preparation and uses thereof

Abstract

The present invention provides a process for preparing microcapsules comprising a core material encapsulated by a metal oxide shell, microcapsules obtained therewith and uses thereof.

What is claimed is: 
     
         1 . Microcapsules comprising a core material encapsulated by a metal oxide shell, wherein the microcapsules are prepared by a process comprising:
 (a) preparing an oil-in-water emulsion by emulsification of an oily phase that comprises a core material, in an aqueous phase, wherein one or both of the oily phase and the aqueous phase comprise a sol-gel precursor;   (b) adding metal oxide nanoparticles to said aqueous phase prior to the preparation of the emulsion of step (a), or adding the metal oxide nanoparticles during the preparation of the emulsion of step (a) or adding the metal oxide nanoparticles after the preparation of the emulsion of step (a); and thereby obtaining a stable emulsion; and   (c) applying conditions to obtain microcapsules;   wherein said core material comprises a pharmaceutically, cosmetically, or agrochemically active ingredient, wherein the active ingredient is in a solid form and dispersed in the core, and wherein said metal oxide is selected from silica, titania, zirconia, ZnO, and mixtures thereof.   
     
     
         2 . The microcapsules of  claim 1 , wherein said core material is a dispersion of the solid active ingredient; wherein the thickness of said metal oxide shell is in the range of 0.1-10 microns, and wherein said shell is obtained from (a) metal oxide nanoparticles, and (b) a hydrolyzed and polymerized sol gel precursor. 
     
     
         3 . The microcapsules of  claim 1 , wherein said core material comprises a dermatologically active agent selected from antifungal agents, antibacterial agents, anti-inflammatory agents, antipruritic agents, anti psoriatic agents, anti acne agents, anti rosacea agents, and combinations of any of the above. 
     
     
         4 . The microcapsules of  claim 1 , wherein said core material comprises an anti acne agent selected form benzoyl peroxide, retinoid, and mixtures thereof. 
     
     
         5 . A composition comprising microcapsules according to  claim 1  and a carrier. 
     
     
         6 . A method for treating a surface condition in a subject, comprising topically administering onto the surface a composition according to  claim 5 , wherein core material comprises a topically acting active agent. 
     
     
         7 . The method of  claim 6 , wherein said surface is skin or mucosal membrane. 
     
     
         8 . The method of  claim 6 , wherein said surface condition is a skin disease or disorder selected from acne, infection, inflammation, pruritis, psoriasis, seborrhea, contact dermatitis, rosacea, and a combination thereof. 
     
     
         9 . A composition comprising microcapsules according to  claim 1 , wherein the core material comprises a topically acting active agent, for treatment of a disease or disorder selected from acne, infection, inflammation, pruritis, psoriasis, seborrhea, contact dermatitis, rosacea, and combination thereof. 
     
     
         10 . A composition for pest control comprising microcapsules according to  claim 1 , wherein said core material comprises a pesticide. 
     
     
         11 . The composition of  claim 10  for crop protection or noncrop pest control. 
     
     
         12 . The composition of  claim 10 , wherein said pesticide is selected from a herbicide, an insecticide, a fungicide, and mixtures thereof.