Inhalative nanomedicine--opportunities and challenges.

Inhalation therapy is still limited by the low bioavailability of the administered drugs. Advantages of the pulmonary administration site like large resorption area, low enzymatic equipment, and circumvention of the first pass effect are set into perspective by the rigid barrier properties of the alveolar region. As a consequence, the systemic bioavailability of peptides and proteins is still relatively limited, even when administered by modern pharmaceutical aerosol technologies. In the context of advanced pulmonary drug therapy the use of nanoparticles as alternative to micronsized drug formulation could be of special interest, because nanoparticles seem to overcome some cellular barriers quite efficiently. Besides such outstanding permeation properties, nanoparticles may also hold promises to escape from pulmonary clearance mechanisms and to allow for cell-specific targeting within the lung. Such opportunities and challenges of inhalative nanomedicine are reviewed in this short review.