Permeability of Liposomal Membranes composed of Unnatural Types of Synthetic Lecithin-Analogues

Abstract

Permeability properties of liposomal membranes composed of the synthetic unnatural type phospholipids (IIa-c, III, IV) are compared with those of the corresponding glyceride-type lecithins (Ia, Ib). Certain synthetic analogues (IIa, III and IV) can retain glucose in the liposomes in nearly same order as that in the saturated long-chain lecithinderived liposomes. Cholesterol fluidizing effect of the lecithin analogues was generally small compared with those of the corresponding lecithins, partly due to bulkiness of trichloromethyl group which may hinder the immobilization of cholesterol along the fatty acid chains. Interestingly, the liposomes derived from enol-type synthetic lipid (III) can regain the barrier ability at the temperatures above the transition temperature just as natural unsaturated-chain lecithins do.