| abstract |
The present invention concerns a process for the preparation of microcapsules having a core-shell structure, wherein said microcapsules have a diameter of approximately 0.1 to 100 micron, wherein each core includes at least one active ingredient, said core is encapsulated within a microcapsular shell, and wherein said shell is comprised of at least one inorganic polymer obtained by a sol-gel process, and said microcapsular shell protects the active ingredient prior to topical application and releases said active ingredient after topical application, said process comprises the steps of; (a) preparing a hydrophobic solution or a hydrophobic dispersion comprising sol-gel precursors and an ingredient to be encapsulated; (b) emulsifying the hydrophobic solution or dispersion of step (a) in an aqueous solution under high shear forces to obtain an emulsion; (c) mixing and stirring the emulsion obtained, with a second aqueous solution, at a selected pH to obtain the sol-gel microcapsules. |