Tumor cell growth inhibition by liposome-encapsulated aromatic polyamidines.

Apart from its antiproteinase activity, the aromatic polyamidine TAPP-Br [the bromo derivative of 1,3-di-(p-amidinophenoxy)-2,2-bis-(p-amidinophenoxymethyl)propane (TAPP-H)] is able to inhibit the in vitro growth of a variety of tumor cell lines, including human melanoma, and breast and kidney carcinoma. We have now shown that TAPP-Br can efficiently be encapsulated into egg phosphatidylcholine vesicles. When incorporated into these liposomes, the inhibitory effect of TAPP-Br is significantly enhanced compared with that of the free drug. Based on these promising results, a proposal is made for the delivery of this antiproliferative agent to tumor cells by using liposomes as the vehicle.