Biodistribution and Therapeutic Utility of Liposomal Drug Carrier Systems

Abstract

Delivery of the drug at a specific site (drug targeting) or controlled and prolonged release of the liposome-bound drug are the two major considerations for adding liposomes to the existing arsenal of drug delivery systems. In particular the concept of liposomal drug targeting has been evolving rapidly in the past 10 years with the development of 'second generation' carriers such as immunoliposomes (liposomes bearing covalently coupled antibodies as homing device) and, more recently, the long-circulating liposomes. In this contribution novel approaches in the field of liposomal drug targeting will be briefly described: (1) immunoliposomes for chemotherapy of intraperitoneal malignancies, such as ovarian carcinoma, (2) a new type of immunoliposomes for mediating the targeting of enzymes to be used for site-specific prodrug activation (immuno-enzymosomes), (3) long-circulating liposomes for the targeting of antibiotics to sites of bacterial infection, and (4) polyethyleneglycol (PEG)-modified proteoliposomes with the homing device coupled to the ends of the long PEG chains for achieving effective target binding along with prolonged circulation times.