Dry Powder form of Polymeric Nanoparticles for Pulmonary Drug Delivery.

Delivery to the lungs is an efficient way to deliver drugs directly to the site of action or to the blood circulation. Because of limitations of direct administration of free drugs, particulate drug delivery systems such as DPI formulations based on nanoparticles (NPs) have been of interest for pulmonary drug delivery. The prolonged residence of NPs in the lungs due to ability to escape from the clearance mechanisms such as mucociliary escalator, macrophage uptake (a size of 1-2 µm is ideal for macrophage phagocytosis), and translocation to the systemic circulation is amongst the key advantages of NPs. By this approach, the controlled pulmonary delivery of drugs, peptides, proteins, genes, siRNA, and vaccines is possible. Both natural (albumin, gelatin, alginate, collagen, cyclodextrin, and chitosan) and synthetic (poly (lactide-co-glycolide) (PLGA), polyacrylates and polyanhydrides) polymers have been used in formulation of pulmonary nanovectors. As direct pulmonary administration of NPs is not feasible, by using the safe excipients, NPs could be converted to dry powder inhaler (DPI) formulations. These can provide a promising deposition and stability of NPs. In this article, the DPI formulations based on polymeric nanoparticles have been reviewed and categorized based on the polymer type used for preparation of NPs.