Screening and biological evaluation of liposomal formulations containing Adriamycin

Liposomal Adriamycin® (L-ADM) suppressed phagocytic activity for more than 1 week. This would contribute to the variation in the biodistribution and toxicological characteristics of L-ADM after repeat administration. This finding suggests that the interval in repeat administration of L-ADM should be more than 1 week. Blood toxicity of L-ADM was affected by the administration schedule. It is expected that the blood toxicity of Adriamycin® (ADM) would be reduced by liposomal encapsulation in clinical use where administration of antitumor agents is usually repeated at intervals of 2–3 weeks. L-ADM had greater antitumor activity against a liver metastatic model, M5076, than ADM. However, no significant enhancement of the effects of liposomal encapsulation was observed in another model, L5178Y-ML. Based on these findings, the problems in exploratory and preclinical studies of liposomal Adriamycin® (L-ADM) are discussed.