Moving boundary problem for diffusion release of drug from a cylinder polymeric matrix

An approximate analytical solution of moving boundary problem for diffusion release of drug from a cylinder polymeric matrix was obtained by use of re fined integral method. The release kinetics has been analyzed for non-erodi ble matrices with perfect sink condition. The formulas of the moving bounda ry and the fractional drug release were given. The moving boundary and the fractional drug release have been calculated at various drug loading levels , mid the calculated results were in good agreement with those of experimen ts. The comparison of the moving boundary in spherical, cylinder, planar ma trices has been completed. An approximate formula for estimating the availa ble release time was presented. These results are useful for the clinic exp eriments. This investigation provides a new theoretical tool for studying t he diffusion release of drug from a cylinder polymeric matrix and designing the controlled released drug.