Liposomes for Drug Delivery

Liposomes are a novel drug delivery system (NDDS), they are vesicular structures consisting of bilalyers which form spontaneously when phospholipids are dispersed in water. They are microscopic vesicles in which an aqueous volume is entirely enclosed by a membrane composed of lipid bilayers. NDDS aims to deliver the drug at a rate directed by the needs of the body during the period of treatment and direct the place of action. Liposomes are colloidal spheres of cholesterol non-toxic surfactants, sphingolipids, glycolipids, long chain fatty acids and even membrane proteins and drug molecules or it is also called vesicular system. It differs in size, composition and charge and drug carrier loaded with variety of molecules such as small drug molecules, proteins, nucleotides or plasmids etc. Few drugs are formulated as liposomes to improve their therapeutic index. Hence a number of vesicular drug delivery systems such as liposomes, niosomes, transfersomes and pharmacosomes are developed. The focus of this chapter is to the various method of preparation, characterization of liposomes, advantages and applications, etc.