SLOW-RELEASE FROM A COATED SPHERE WITH SLIGHT DEFORMATIONS OF COATINGFILM AND DRUG MATRIX

This paper, a continuation of our previous work, is a presentation of the effects of slight deformations of both the coating film and the dr ug matrix on the concentration distributions and the slow release char acteristics of a coated drug particle, The coated particle shape, in p ractice, is not perfectly spherical. With restriction of the deformati on shape functions considered, it is noted that if the deformation is slight or if only the average release rate is of interest! the effects of shape deformation are secondary. Otherwise, the shape deformation can have a significant effect on the concentration profiles and/or the release rate from different parts of the particle surface. The deform ations of both coating film and the drug matrix could introduce a grea ter deviation from the spherical case than those considering only coat ing film or drug matrix shape deformation.