EFFECT OF SULFATIDE-INSERTED LIPOSOMES CONTAINING ENTRAPPED ADRIAMYCIN ON METASTASIZED CELLS IN LYMPH-NODES

The delivery of adriamycin (ADM) to mouse inguinal lymph nodes containing metastasized mammary adenocarcinoma cells was investigated. Tumor cells of a transplantable mammary adenocarcinoma (MM48) were implanted into a hind footpad of a mouse to produce a model of inguinal lymph node metastasis. Upon subcutaneous injection into the thigh of the mouse, ADM entrapped in sulfatide-inserted liposomes (Lip-ADM) brought about much more efficient delivery of the drug than did free ADM. The administration of 8 mg ADM/kg body weight of Lip-ADM resulted in a tissue concentration of 12.5-mu-g/g tissue (23.0 nmol/g tissue) in the lymph node containing metastasized cells, which value was approximately 2-fold higher than that achieved in the group administered free ADM. In accordance with the efficient delivery, Lip-ADM resulted in an increase in the growth suppression effect of the drug on the tumor as compared with free ADM. As the data indicated that the antitumor effect was significantly greater in the group receiving Lip-ADM than in the one receiving free ADM, Lip-ADM would be useful for treatment of tumor cells that have metastasized to the lymph nodes.