Nanosized and Nanostructured Particles in Pulmonary Drug Delivery

Nanosized objects can be used as the drug carriers with specific functionalities which are introduced to the body via the respiratory system, i.e., by inhalation. They can be carried in as aerosol nanoparticles (NPs), nanostructured particles (NSPs) or components of nanosuspensions atomized into micrometer-sized droplets. In the first part of the paper physical factors required for the effective inhalation of nanocarriers are discussed, including the flow dynamics of NPs and NSPs in the respiratory tract. Selected problems related to designing of the required properties of inhalable drug carriers are also addressed. In the next part of the paper, the importance of direct physicochemical interactions between deposited nanoparticles and pulmonary fluids (pulmonary surfactant and bronchial mucus) is emphasized. This perspective allows for a more rational definition of the efficient strategies of the delivery of nanoparticle drug carriers via inhalation.