CONTROLLED-RELEASE OF POLY-D,L-LACTIC ACID-CONTAINING BLEOMYCIN

By use of four types of in vivo degradable polylactic acid (PLA), i.e. PLA with an average molecular weight of 1500 (1500DL), 2200 (2200DL), 2800 (2800DL) and 3500 (3500DL), preparations of bleomycin (BLM)-cont aining solid forms (polymers) were tested. The in vitro release of BLM from the polymers was also examined in an immersion system. By the me lt-pressing technique, five types of BLM (2.5 mg) containing solid for ms, i.e. 1500DL polymer, 2200DL polymer, 2800DL polymer, 3500DL polyme r and 1500DL + 3500DL (a mixture of 1500DL and 3500DL) polymer were pr epared. In all five types of polymers, cumulative BLM release was cont rolled to less than 5% by the third day and no initial burst of the re lease was observed. BLM release from the polymer continued for 3 weeks at the shortest and 6 weeks at the longest. Various polymers containi ng BLM could be useful for the site of drug administration or anti-can cer release pattern.