Trends and developments in liposome drug delivery systems

Since the discovery of liposomes or lipid vesicles derived from self-formin g enclosed lipid bilayers upon hydration, liposome drug delivery systems ha ve played a significant role in formulation of potent drugs to improve ther apeutics. Currently, most of these liposome formulations are designed to re duce toxicity and to some extent increase accumulation at the target site(s ) in a number of clinical applications. The current pharmaceutical preparat ions of liposome-based therapeutics stem from our understanding of lipid-dr ug interactions and liposome disposition mechanisms including the inhibitio n of rapid clearance of liposomes by controlling size, charge, and surface hydration. The insight gained from clinical use of liposome drug delivery s ystems can now be integrated to design liposomes targeted to tissues and ce lls with or without expression of target recognition molecules on liposome membranes. Enhanced safety and heightened efficacy have been achieved for a wide range of drug classes, including antitumor agents, antivirals, antifu ngals, antimicrobials, vaccines, and gene therapeutics. Additional refineme nts of biomembrane sensors and liposome delivery systems that are effective in the presence of other membrane-bound proteins in vivo may permit select ive delivery of therapeutic compounds to selected intracellular target area s. (C) 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:667-680, 2001.