Preparation and disposition of asialofetuin-labelled liposome.

A liposome labelled with asialofetuin(AF-liposome) was prepared by the detergent dialysis method. Asialofetuin in the amount of 34-68 micrograms were imposed among the 1 microM of phospholipids constituting the outer surface of liposome. The AF-liposome containing [14C]-cholesterol in the lipid layer and [3H]-sucrose in the aqueous layer was intravenously administered to rats. Both radioactivities were biphasically cleared from systemic circulation at rates faster than that of the fetuin-labelled liposome. These radioactivities were recovered in the liver by about 90 per cent within 60 min, and per gram of tissue, were highest in this organ. In an in vitro experiment using isolated rat hepatocytes, the high affinity of the AF-liposome toward hepatocytes was observed from scanning electron micrographs. Based on these findings, the AF-liposome may possibly be stable in circulation and function as a carrier of encapsulated drugs to hepatocytes.