Drug-carrier Property of Albumin Microspheres in Chemotherapy. V. Antitumor Effect of Microsphere-entrapped Adriamycin on Liver Metastasis of AH 7974 Cells in Rats

Bovine serum albumin microspheres containing adriamycin were prepared by heat solidification of albumin in albumin-adriamycin aqueous solution in cottonseed oil emulsions. The efficiency of the microspheres as a drug carrier of adriamycin was evaluated in liver metastasis caused by the injection of AH 7974 tumor cells into the portal vein of rats as a model of release of such cells into the vein during the course of surgical removal of gastric cancer. Adriamycin entrapped in the microspheres exhibited sustained in vitro release which followed first-order kinetics. After intraportal injection in rats, the microspheres and entrapped agent distributed mainly in the liver, and the disappearance rate from the tissue was very slow in comparison with that of free drug. The survival times of rats bearing AH 7974 liver metastasis were prolonged by intraportal administration of microspheres containing adriamycin. In contrast, free adriamycin or microspheres without entrapped drug did not significantly increase the life span over the control. These results suggest that albumin microspheres containing adriamycin may be applicable as a drug carrier in the adjuvant chemotherapy of liver metastasis