The antitumor effects of adriamycin entrapped in liposomes on lymph node metastases

Adriamycin (ADM) entrapped in liposomes (Lip-ADM) was prepared and its therapeutic effects studied using the mouse leukemia cell line, P388, which metastasized to axillary lymph nodes after inoculation into the foot pads of CDF1 mice. Lip-ADM injections (7.5 mg/kg) were given into the foot pad at two-day intervals. Two series of experiments were performed; one in which Lip-ADM was administered on days 1,3 and 5 following tumor inoculation, and the other in which it was administered on days 5 and 7. Both Lip-ADM injection regimens significantly inhibited metastases to the lymph nodes as compared with mice given injection of saline solution. Furthermore, the therapeutic effects of three Lip-ADM injections were significantly greater than the effects of free ADM. Histological examinations of lymph nodes revealed that three injections of Lip-ADM completely eliminated tumor cells, whereas viable tumor cells were still observed in the lymph nodes after treatment with free ADM. The results of this study suggest that Lip-ADM is useful for the treatment of lymph nodes metastases and that the local injection of Lip-ADM, through such means as endoscopy, would be recommended as a clinical mode of application.