Liposomes as Systemic and Mucosal Delivery Vehicles
Background Liposomes are microscopic, spherical phospholipid bilayers which contain an aqueous internal environment They were first described by Bangham et al. (1965), who demonstrated that liposomes could entrap solutes such as cations and anions. In these studies it was revealed that liposomes containing entrapped anions, Cl−, and I−, were shown to be more permeable than liposomes containing entrapped cations, such as Na+ and K+. Subsequent work identified the utility of liposomes in drug delivery and liposomes have since been used to administer a wide range of pharmaceutical compounds such as anti-microbial and anti-cancer agents. Entrapment of drugs into liposomes often resulted in reduced toxicity and prolonged circulation time compared with the drug alone. Licensed products include AmBisomes® and Abelcet® which contain amphotericin B in a liposome formulation, for the treatment of systemic fungal infections, and DOX-SL® and DaunoXome® which respectively contain doxorubicin and daunorubicin in a liposome formulation for the treatment of Karposi’s sarcoma.