A Novel Dissolution-Diffusion Model for Investigation of Drug Release from Polymeric Microspheres

A new model was developed for drug release from microspheres. Drug dissolution, diffusion, moving front, and size distribution were considered as main release mechanisms. The proposed dissolution-diffusion model was solved numerically for analysis of dissolved drug concentration profiles. In comparison with Fickian diffusion model and Koizumi model, the proposed model is characteristic of the whole release process without limitation of dissolution rate or dissolubility. Further, the in vitro controlled release kinetics of nifedipine loaded microspheres of PLA and PLGA was investigated by the proposed modelling method.