Innovative pMDI formulations of spray-dried nanoparticles for efficient pulmonary drug delivery

Abstract For drug delivery to the lungs, the aerodynamic size of drug particles plays a predominant role in determining the sites of deposition in the airway, and the particles with the size less than 2 μm are highly expected as they will be preferably delivered to the ideal site of alveolar regions. In this paper, a novel platform technology has been developed, where the water (containing pharmaceutically active agents)-in-oil (w/o) microemulsions were spray-dried to generate nanosized drug particles that were able to be homogeneously dispersed in the propellant to form an exceptionally stable suspensions with no precipitates or flocculates during a long time storage. High fine particle (