[Drug release kinetics of ibuprofen coated granules and their in vitro-in vivo correlation].

A sustained release of ibuprofen granules coated with ethyl cellulose has been studied both in vitro and in vivo with a selected formulation. The drug release process follows Higuchi equation when coating extent is low, and zero-order kinetics when coating extent is high. The primary factors that influence drug release include granule size, coating extent, pH of dissolution medium and pressure. The release rate decreases when either granule size or coating extent increases or pH value decreases. The release rate increases greatly when the coated granules are compressed directly into tablets in that the coating film is destroyed. The results from oral administration of coated granules by seven healthy volunteers show that the in vitro and in vivo correlation of drug release from coated granules is highly significant.