ABSTRACT
The system most investigated for controlled release comprises incorporating a biologically active agent in a matrix, commonly a polymeric material, shaping the obtained composite into a convenient form, and implanting it into the body tissue or body cavity by surgery or injection. Composites of drugs with erodible matrices, which are consumed or biodegraded during therapy, were developed by S. Yolles in the study of controlled release of narcotic antagonists. An erodible intrauterine device has been made by crosslinking gelatin with ketones and incorporating prostaglandin. In searching the literature for erodible matrices, very few references have been found on the following polymers and copolymers and their use as matrices. However, investigation in the field of controlled release is going forward at a feverish rate, including the search for new and patentable bioerodible polymers.
