1993 Volume 16 Issue 10 Pages 960-964
The influence of HCO60 on the blood clearance and tissue distribution of soybean phosphatidylcholine (PC) liposomes, encapsulating α-tocopherol as a marker, was studied in rats. The liposomes were prepared by the hydration method from a lipid film containing different amounts of HCO60, and by extrusion through a 0.1 μm polycarbonate membrane filter. The blood clearance and liver uptake of α-tocopherol after i.v. administration increased with increasing the amount of HCO60 the liposome contained. With 80 wt% HCO60 liposomes, the accumulation of α-tocopherol in the liver was approximately three-fold that of the 100% PC liposomes. The uptake by lungs, spleen and kidneys did not change with the addition of HCO60. The findings obtained in a gel-filtration study suggested that α-tocopherol is not removed from the liposomes, with or without HCO60, by rat plasma proteins and the HCO60 micelle may form a complex with rat plasma proteins. Our findings suggest that liposomes containing large amounts of HCO60 (more than 60 wt%) will be useful for delivering drug to the liver.