PULMONARY DELIVERY OF LIPOSOMES

An overview of current data on pulmonary delivery of liposomes is provided, entailing fate of aerosols in the respiratory tract, physicochemical characterization of liposome aerosols, their therapeutic applications, pulmonary fate and kinetics, and pulmonary safety. Drugs that have been investigated for pulmonary delivery via liposomes include anticancer agents (ara-C), antimicrobials (enviroxime, amikacin, pentamidine), peptides (glutathione), enzymes (superoxide dismutase). antiasthmatic and antiallergic compounds (metaproterenol, salbutamol, cromolyn sodium, corticosteroids). Promising developments including pulmonary delivery of immunomodulators, antiviral agents and gene constructs (cystic fibrosis, alpha1-antitrypsin gene) are also discussed. Finally, pulmonary deposition and kinetics of drugs delivered via liposome aerosols, and targeting strategies to deliver drugs selectively to infected or impaired phagocytic (alveolar macrophages) and nonphagocytic (epithelial) cells in the lung are outlined. Based on the data on therapeutic efficacy and pulmonary safety currently available, we conclude that liposome aerosols may play an important future role in the therapy of pulmonary diseases including intracellular infections, immunologic disorders, and gene defects.