Sustained release of cisplatin from multivesicular liposomes: Potentiation of antitumor efficacy against S180 murine carcinoma

Cisplatin was encapsulated into multivesicular liposomes (MVLs) and the entrapment efficiency, size distribution, and in vitro drug release characteristics of the cisplatin‐MVLs were studied. Pharmacokinetics, tissue distribution, and therapeutic efficacy of cisplatin‐MVLs were compared against injection of cisplatin solution into mice inoculated with the murine carcinoma 180 (S180) tumor. The results showed that the cisplatin‐MVLs were capable of high drug loading (0.148:1 mg cisplatin/mg lipid) and high encapsulation efficiency (>80%). The mean diameter of cisplatin‐MVLs was 17 μm. In vitro studies of cisplatin‐MVLs in saline solution showed that they sustained release of encapsulated drug for >7 days. Cisplatin‐MVLs showed higher drug accumulation in the liver, spleen, and tumor regions than cisplatin solution, as well as higher plasma concentrations and a longer circulation time. The therapeutic efficacy of the cisplatin‐MVL preparation against S180 tumor‐bearing mice is significantly higher than that of cisplatin solution. © 2004 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:1718–1724, 2004