New liposome development: Screening and biological evaluation of liposomal formulations containing Adriamycin(R)

Liposomal Adriamycin(R) (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(R) (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(R) (L-ADM) are discussed.