CONTROLLED-RELEASE PELLETS BY EXTRUSION-SPHERONIZATION

A radial basket-type extruder and a serrated plate spheronizer were used to prepare spherical pellets with inherent modified-release properties. A Box-Behnken response surface experimental design was employed to address the effects of altering the concentrations of Eudragit RS 30 D, Avicel RC-591, fumaric acid, and acetyltributyl citrate on pelletization of a low density drug. Response surfaces were adequately described by quadratic equations which also contained significant interaction terms. Optimum ingredient concentrations were selected from the response surface equations and validated in subsequent experiments. The models successfully predicted formulation requirements for meeting selected acceptance criteria. Controlled release pellets were produced that met dissolution specifications without subsequent coating.