Liposome stability and formation: experimental parameters and theories on the size distribution.

The most important characteristics of liposomes, in addition to chemical composition and surface properties, are size distribution and lamellarity. Liposomes can be formed by many different preparation techniques, which according to the literature yield rather well defined vesicle preparations. In contrast to abundant information on the experimental procedures and preparation protocols the theoretical understanding of these processes is lacking. Only geometrical models of structural changes exist for few preparation procedures and size of the liposomes prepared by sonication and detergent depletion method were estimated using simple models. In this paper we first outline different theories on the stability of liposomes and their influence on the size distribution. In the experimental section we shall briefly present the importance of size distribution in experimental work and influence of various experimental parameters on the size distributions obtained.