Studies on liposome-encapsulated carboquone. IV. Enhancement of antitumor activity of carboquone against Ehrlich ascites carcinoma by encapsulation.

The antitumor effects of liposome-encapsulated carboquone (CQ-liposome) were studied following intraperitoneal administration into mice bearing Ehrlich ascites carcinoma (EAC). CQ-liposome showed nearly 3 times superior efficiencies to parent CQ (free CQ) in the growth inhibitory effect on EAC cells inoculated in mice, and also showed almost the same toxicity as free CQ in normal mice. CQ-liposome prolonged the life span of EAC bearing mice about 2 times that of free CQ. In the results of electrophoresis, it was found that CQ-liposome and EAC cells had positive and negative surface charges, respectively. These observations suggest that CQ-liposome is a favorite delivery system to enhance the efficiency of CQ to EAC in mice. One of the reasons for its excellent effect may be explained by an easy contact of CQ-liposome with EAC cells because of its opposite surface charges.