LIPOSOMES : A NOVEL DRUG DELIVERY SYSTEM

Almost from the time of their discovery the demonstration of their entrapment potential, liposomal vesicles have drawn attention of researchers as potential carriers of various bioactive molecules that could be used for therapeutic applications. Liposomes have been widely investigated since 1970 as drug carriers for improving the delivery of therapeutic agents to specific sites in the body. Liposomes, which are biodegradable and essentially non‐toxic vehicles, can encapsulate both hydrophilic and hydrophobic materials, and are utilized as drug carriers in drug delivery systems. As a result, numerous improvements have been made, thus making this technology potentially useful for the treatment of certain diseases in the clinics. Many liposome‐based DNA delivery systems have been described, including molecular components for targeting given cell surface receptors or for escaping from the lysosomal compartment. The insight gained from clinical use of liposome drug delivery systems can now be integrated to design liposomes that can be targeted on tissues, cells or intracellular compartments with or without expression of target recognition molecules on liposome membranes. The success of liposomes as drug carriers has been reflected in a number of liposome‐based formulations, which are commercially available or are currently undergoing clinical trials.