Liposome Delivery Systems for Inhalation: A Critical Review Highlighting Formulation Issues and Anticancer Applications

This was a critical review on research conducted in the field of pulmonary delivery of liposomes. Issues related to mechanism of the nebulization and liposome composition were appraised and correlated with the literature reports of liposome formulations used in clinical trials to understand the role of liposome size and composition on therapeutic outcome. A major highlight was the liposome inhalation for the treatment of lung cancers. Many in-vivo studies that explored the potential of liposomes as anticancer carrier systems were evaluated including animal studies and clinical trials. Liposomes can entrap anticancer drugs and localize their action in the lung following pulmonary delivery. Safety of inhaled liposomes incorporating anticancer drug depends on the anticancer agent used and the amount of drug delivered to the target cancer in the lung. The difficulty of efficient targeting of liposomal anticancer aerosols to the cancerous tissues within the lung may result in low dose reaching the target site. Overall, following the success of liposomes as inhalable carriers in the treatment of lung infections, it is expected that more focus from research and development will be given to designing inhalable liposome carriers for the treatment of other lung diseases including pulmonary cancers. Successful development of anticancer liposomes for inhalation may depend on future development of effective aerosolization devices and better targeted liposomes to maximize benefit of therapy and reduce potential of local and systemic adverse effects.