The deposition of drug particles in the respiratory tract is closely related to their aerodynamic diameter.Generally,only those particles with the size less than 7 μm can be inhaled into the lower respiratory tract,and less than 2 μm can further go into the alveolar regions that are the ideal sites for drug delivery to the lungs.Spray-drying is a one step process that can be used to prepare drug particles for inhalation.But the general spray-drying process employs air pressure to produce millions of droplets containing drugs,which would generate dry particles with the typical size of 3-10 im.The newly developed nano spray drying employs high frequent vibration to produce a cloud of miniature droplets that are subsequently dried to generate dry particles with the size of approximately 1 μm that is the ideal size for the drug delivery to the peripheral regions of the lungs [1].