[Studies on biodegradable microspheres containing mitomycin C].

For the purpose of enhancing antitumor effects, we prepared heated albumin microspheres containing an antitumor drug, mitomycin C. The biodegradable MMC microspheres which have an average diameter of 45 +/- 8 mum contain approximately 10% of MMC and release in vitro approximately 20% of the MMC over 3-day period. The microspheres were injected into albino rabbit femoral artery of the hind leg into which a VX-2 tumor had been implanted. Peripheral blood levels of MMC were reduced as compared to the conventional MMC group, within 60 minutes after injection. Subsequently in the MMC-microsphere administered rabbits, the level was higher than in the conventional MMC administered group. The survival of VX-2 tumor-bearing rabbits prolonged markedly with MMC microspheres.