Inhaled Liposomes-Current Strategies and Future Challenges

Inhalation of therapeutic aerosols is a long established means of delivering drugs topically to the lungs or to the systemic circulation. In addition to drug solutions, suspensions and particulates, liposomal formulations are being developed for aerosol administration. This review summarises the current state-of-the-art in pulmonary liposome delivery. Requirements for successful liposomal aerosol formulations are highlighted as well as the impact of different nebuliser systems on liposomal stability. The results of in vitro and in vivo studies using liposomal aerosols in the treatment of microbial infections, targeting of macrophages, anti-cancer therapy, and the delivery of biopharmaceuticals are discussed. Due to their versatility and biocompatibility, liposomes are promising candidates for pulmonary drug delivery that enable the delivery of compounds with formulation issues (e.g., lipophilic drugs and sensitive biopharmaceuticals) and to create a drug depot in the lung for sustained release.