Different types of liposomes composed of a variety of lipids have been compared for their ability to incorporate captopril and propranolol hydrochloride. Multilamellar liposomes (MLV) prepared from egg phosphatidylcholine (EPC) allowed only low levels of entrapment for both drugs, but the entrapment was increased by inclusion of cholesterol or charged lipids into the vesicle bilayer. The freeze - thawing vesicles (FTV) showed higher encapsulation efficiency and lower permeability properties than MLV. The Influence of surface charge, presence of trehalose and ionic strength of the medium on the encapsulation efficiency of FTV was also investigated. The results revealed that the formation of large liposomes by this technique which probably results from fusion of vesicles is strongly inhibited by increasing the ionic strength and by the presence of trehalose. Producing liposomes by the reverse -phase evaporation technique (REV) resulted in more than 2-fold increase in liposomal uptake of both drugs compared to MLV of the same composition. The rate of drug efflux from liposomes was determined in-vitro and was dependent upon bilayer composition and the method of preparation.