Characterization and tissue distribution of liposomes containing lactose mono-fatty acid derivatives

In this study we characterized liposomes containing the synthetic glycolipids, lactose mono-fatty acid esters (LFEs), whose structures were the most simple ones compared to the other synthetic glycolipids. Gel filtration chromatography was used to confirm that 78 per cent of lactose monostearic acid ester (LSE) or 85 per cent of lactose monoarachidic acid ester (LAE) existed in the liposomal fraction. The size distribution of liposomes containing LFEs was similar to that of the control liposomes which did not contain LFEs. Liposomes containing LFEs were aggregated by Ricinus communis agglutinin from caster bean (RCA120) while the control liposomes were not, with the agglutinability of the liposomes containing LAE being greater than that of those containing LSE. These findings therefore suggested that the LFEs were incorporated into the liposomal membrane with the galactose residues exposed to the outer aqueous phase. Next, the tissue distribution of liposomes containing LAE at 30 min after intravenous administration was compared to that of the control liposomes in rats. Hepatic uptake was 2-fold higher than that of the control liposomes. These results thus demonstrate that liposomes containing LFEs represent potential drug carriers to the liver.