[Drug distribution and antitumor effect of bleomycin incorporated in poly DL-lactic acid in rats].

Two bleomycin (BLM)-containing agents (BLM-PLA, BLM-SOL) were prepared, and the drug distribution and antitumor effect were studied. BLM-PLA is an agent in which BLM is incorporated into biodegradable low-molecular-weight polylactic acid, and BLM-SOL is an aqueous solution of BLM. BLM-PLA or BLM-SOL was subcutaneously administered in the back of rats. When BLM-PLA was implanted, high BLM activity of the connective tissues near the implants was maintained for 2 weeks. On the other hand, BLM activity was very low when BLM-SOL was administered. The effects of BLM-PLA, BLM-SOL and nontreatment on tumor growth and survival time were compared using subcutaneous tumor of Yoshida sarcoma in 21 rats each. The survivors and mean survival time in BLM-PLA group, BLM-SOL group and nontreatment group was 14 and 44.6 days, 5 and 23.7 days, and 0 and 11.3 days, respectively. BLM-PLA was superior to BLM-SOL in both drug distribution and antitumor effect, and consequently BLM-PLA could be a useful tool in loco-regional chemotherapy.