Resorcinolic lipids improve the properties of sphingomyelin-cholesterol liposomes.

Alkylresorcinolic lipids isolated from cereal grains and their semi-synthetic myristoyl-sulphonyl derivatives (MSAR) were used to modify small long-circulating sphingomyelin-cholesterol liposomes. Those SM:Chol vesicles modified with 10-30 mol% resorcinolic lipids had stable size and low membrane permeability in vitro at 4 degrees C and 37 degrees C. Liposomes containing 30 mol% MSAR showed very fast solute release in the presence of human plasma at 37 degrees C, which was drastically diminished in heat-inactivated plasma. In vivo studies showed that unmodified SM:Chol liposomes and those modified with alkylresorcinols were eliminated from the circulation more slowly than liposomes with the highest concentration of MSAR in membrane and were located mostly in the liver and spleen.