Vesicular and Stealth Vesicular Drug Delivery – A Review

Vesicular systems (liposomes), one of several potential novel drug delivery systems, provide an advanced technology for delivering active compounds to the site of action, and numerous formulations are currently in clinical use. Liposome technology has developed from typical vesicles to sterically stabilised vesicles, which produce long-circulating liposomes by varying the lipid content, size, and charge of the vesicle. Several compounds, such as glycolipids, have been used to create liposomes with changed surfaces. The addition of the synthetic polymer poly-(ethylene glycol) (PEG) in liposome composition was a crucial milestone in the creation of long-circulating liposomes. PEG on the liposomal carrier's surface has been found to increase blood circulation time while decreasing mononuclear phagocyte system uptake (Stealth Liposomes). As a consequence of this technique, a vast variety of liposome formulations encapsulating active compounds have been developed, all of which have excellent target efficiency and activity. Stealth liposomes can also be actively targeted with monoclonal antibodies or ligands thanks to a synthetic alteration of the terminal PEG molecule. This article focuses on vesicular drug delivery as well as stealth technology and presents preclinical and clinical data for the most common liposome formulations, as well as discussing developing developments in this promising technology.