Patent ID: 8435559
Filing Date: 2013-05-07
Classification: A61K,A61P,A61Q,B01J

Abstract:
1. A method for controlling the shell thickness of microcapsules greater than or equal to 18 nanometers, wherein the microcapsules are prepared by I) mixing an oil phase and an aqueous solution of a cationic surfactant to form an oil in water emulsion, II) adding a water reactive silicon compound comprising a tetraethoxysilane to the oil in water emulsion, III) polymerizing the tetraethoxysilane at the oil/water interface of the emulsion to form microcapsules having a core containing the oil and a shell, said method comprises: (i) selecting the weight % of cationic surfactant to the oil phase in the emulsion of step I) ranges from 0.1% to 0.3%, and (ii) selecting the oil phase, the amount of the oil phase, and the amount of tetraethoxysilane used in the process so that the thickness of the resulting microcapsules satisfies the following equation: where PS is particle size (Dv 0.5) expressed in micrometers; payload=Volume oil phase*100/(Volume oil phase+Volume shell); Volume oil phase=Mass oil phase/density of oil phase; and Volume shell=Mass tetraethoxysilane*0.288/2.