Overview of Inhaled Nanopharmaceuticals.

Nanopharmaceuticals represent a group of nanoparticles engineered for medical purposes. Nowadays, nanotechnology offers several possibilities to improve the safety and efficacy of medicines by designing advanced carrier systems which have been found to offer particular advantages when formulated in the nanoscale. Some of the initially marketed nano-formulations already demonstrate advantages over conventional formulations. Innovative delivery systems offer the possibility to not only control drug release but also to overcome biological barriers. For the translation of new drug products from bench to bedside, however, it is pivotal to test and prove their safety. This is of course also true for nanopharmaceuticals, where in particular the biocompatibility and also the clearance/biodegradation of the carrier material after drug delivery has to be demonstrated. The pulmonary route offers some great opportunities for noninvasive drug delivery but also implicates peculiar challenges. Advanced aerosol formulations with innovative drug carriers have already contributed to the significant progress of inhalation therapy. However, in spite of the large alveolar epithelial surface area, the respiratory tract still features diverse efficient biological barriers, primarily designed by nature to protect the human body against inhaled pollutants and pathogens. Only a thorough understanding of particle-lung interactions will allow the rational design of novel nanopharmaceuticals capable of overcoming these barriers, while of course always keeping in mind the strict demands for their safety. While the recent resurrection of inhaled insulin has already confirmed the potential of the pulmonary route for systemic delivery of biopharmaceuticals, inhaled nanopharmaceuticals, currently under investigation, promise to improve also local therapies like anti-infectives.