EFFECT OF ADRIAMYCIN ENTRAPPED IN SULFATIDE-CONTAINING LIPOSOMES ON COLON-TUMOR CELLS METASTASIZED TO THE LIVER

Antineoplastic effect of adriamycin entrapped in sulfatide-containing 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 72 h 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 +/- 1.0 nmol/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 6 mg/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.