Preparation and characterization of ceramide-based liposomes with high fusion activity and high membrane fluidity

Liposomes are useful vesicles that deliver drugs effectively to various organs. For transdermal applications, liposomes with high membrane fluidity, high fusion activity, and comprising stratum corneum lipid have been used for drug delivery. With the aim to increase drug distribution to the skin, we developed new liposomes with three characteristics: high membrane fluidity, high fusion activity to the stratum corneum lipid liposomes (SCLL), and lipid compositions based on stratum corneum lipids. New liposomes were prepared based on SCLL. First, lipid compositions of SCLL were optimized. Second, the alkyl chain length of ceramides and fatty acids, and the saturation degree of fatty acids were altered. As a result, liposomes with the highest membrane fluidity and fusion activity to SCLL were composed of C-8 ceramide/cholesterol/linolenic acid/cholesterol sulfate = 45/5/5/45 (w/w%), and named C8L. C8L had 1.54-times greater membrane fluidity and 6.57-times greater fusion activity to SCLL than SCLL. Transmission electron microscopy revealed that C8L had a spherical structure. The surface charge and the particle size were approximately -47.7 mV and 184 nm, respectively. Thus, in the future, C8L will be used to facilitate drug delivery to the skin.