LIPOSOMES PREPARED FROM SYNTHETIC AMPHIPHILES .2. THEIR INTERACTION WITH EHRLICH ASCITES TUMOR-CELLS AND TISSUE DISTRIBUTION IN EHRLICH SOLID TUMOR-BEARING MICE

The interaction of 99mTc-labeled liposomes prepared from synthetic amphiphiles containing amino acid residues with Ehrlich ascites tumor cells in vitro and their tissue distributions in Ehrlich solid tumor-bearing mice were investigated. The amphiphiles used were A^,A^-didodecyl-A^-[6-(trimethylammonio)hexanoyl]-L-alaninamide bromide (N + C5 Ala-20 12), iV,Ar-didodecyl-Aa-{6-[dimethyl(2-carboxyethyl)ammonio]hexanoyl}-L-alaninamide bromide (CAC2N + C5 Ala-2012) and 5’-{l-carboxy-2-([2,3-bis(hexadecyloxy)propoxy]carbonyl)ethyl}homocysteine (HcyM“G2C16). Most of the radioactivity of N+C5Ala2C12and CAC2N + C5Ala2C12liposomes was firmly bound to Ehrlich ascites tumor cells in vitro. On the other hand, the accumulation of three 99mTc-labeled liposomes in the tumor of Ehrlich solid tumor-bearing mice was low (about 1% dose per gram of tissue), and most of the liposomes were taken up highly in the liver and spleen of the tumor-bearing mice. However, the radioactivity of the liposomes in the tumor, especially that of N+C5Ala2C12and CAC2N + C5Ala2C12liposomes, decreased more slowly with time than in the liver in up to 24 h after injection, suggesting that these liposomes were hard to separate from the tumor cells. © 1990, The Pharmaceutical Society of Japan. All rights reserved.