Antitumor Effect of Liposome‐entrapped Adriamycin Administered via the Portal Vein

Abstract

We examined the distribution in tissues and antitumor effect of freeze-dried liposome-entrapped adriamycin (Lipo-ADM) administered via the portal vein to rabbits bearing VX2 tumors. Liposomes composed of egg phosphatidylcholine (cholesterol 50 mol%) were used as drug carriers. The liver concentration of ADM increased after delivery and cardiac uptake decreased compared with free drug treatment. The in vivo antitumor effect of Lipo-ADM was determined in rabbits inoculated with VX2 tumor. Repeated injections of free ADM via the portal vein prolonged the life span of tumor-bearing rabbits. The life span was further prolonged by Lipo-ADM treatment compared with the control group and the free ADM group. Histological examination revealed that the damage to the liver caused by Lipo-ADM administered via the portal vein did not differ from that observed in animals treated with free ADM. These results indicate that portal vein administration of Lipo-ADM may be more effective in dealing with liver metastases than treatment with free ADM and may be therapeutically useful without toxic side effects.