ABSTRACT
I. INTRODUCTION In the early 1960s, Alec Bangham [1] first described how membrane molecules, e.g., phospholipids, interact with water to form unique structures now recognized as liposomes. Considered a mere curiosity just some 30 years ago, liposomes are now established as a useful model membrane system, and they have demonstrated potential for delivering molecules as large as DNA to the intracellular compartment of cells. More important, liposomes have shown great potential as a drug delivery system. An assortment of molecules, including peptides and proteins, have been incorporated in liposomes, which can then be administered by different routes. Various amphiphathic molecules have been used to form the liposomes, and the method of preparation can be tailored to control their size and morphology. Drug molecules can either be encapsulated in the aqueous space or intercalated into the lipid bilayer; the exact location of a drug in the liposome depends on its physicochemical characteristics and the composition of the lipids.
