Effect of Adriamycin Entrapped in Sulfatide-Containing Liposomes on Colon Tumor Cells Metastasized to the Liver

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Antineoplastic effect of adriamycin entrapped in sulfatidecontaining liposomes on colon tumor cells metastasized to the liver and preventive effect of the liposome-entrapped adriamycin on liver metastasis were studied by use of an in vivo murine model for liver metastasis made by portal injection of cells of colon 26, a murine colon cancer cell line. The levels of adriamycin in the liver at 24 and 72h after intravenous administration of the drug entrapped in sulfatide-containing liposomes were 68.2±8.7 and 47.5±12.0 nmol/g liver tissue, respectively. In the case of free adriamycin, those levels were 3.1±1.0 and 2.4±1.0nmol/g tissue. These results indicate that upon entrapment of adriamycin in the liposomes, a higher level of the drug was maintained in the liver for a longer time than the free drug. Administration of 6mg/kg of adriamycin entrapped in liposomes at 7 days after the injection of colon 26 cells brought about a significant reduction in the number of colonies on the liver surface counted at 14 days after cell injection compared with the free drug (p<0.05). The pretreatment with adriamycin entrapped in liposomes resulted in the absence of colonies in 4 of 6 mice and significantly prolonged their survival time (p<0.05). These results indicate that liposomal adriamycin is effective in the treatment of liver metastasis.