MODELING AND SIMULATION OF DRUG-RELEASE FROM GRANULE COATED WITH AN AQUEOUS-BASED SYSTEM OF ACRYLIC COPOLYMER

In a previous paper, [Watano et al., Chem. Pharm. Bull., 42, 2338 (199 4)], we proposed a simple model which could be used to analyze data of controlled release of a water-soluble drug from spherical particles c oated with an aqueous-based system of acrylic copolymer by a tumbling fluidized bed process. The model predicted that the fractional release of drug was related to exponential of release time, and drug release data of several samples prepared with various levels of operational mo isture content were studied to determine the effect of this content on film thickness and drug permeability. In this study, to confirm the m ethod's validity, we simulated the drug release rate at various moistu re content and coating levels using the proposed model. The simulated results were compared with the experimental data to evaluate the accur acy of the model. The mechanism of aqueous coating was also described using the simulated results.