A NEW GRADIENT MATRIX - FORMULATION AND CHARACTERIZATION

A gradient matrix system for potential zero order release of drug is p resented. The device consists of a cylinder composed of a hydrophobic polymer which is characterized by a concentration gradient along its l ength. The manufacturing process is described. It consists of controll ed sedimentation by centrifugation in a melted polymer. The gradient i s characterized by measuring concentration and particles distribution. The effects of the process parameters are studied. It is shown that t he device can approximate a zero order kinetic of release.