Nano spray-dried powders for pulmonary drug delivery

XU En-yu; JIANG Jun-feng; XU Ying; WANG Yang; LI Hao-ying

Abstract：Objective:To prepare nano spray-dried (NSD) drug particles with diameters in the range for efficient delivery to alveoli and investigate the effects of different excipients on the NSD powders to obtain dry powder inhalation (DPI)with improved flowability,dispersibility,and deposition in lungs.Methods:The NSD powders loaded with salbutamol sulphate were prepared with lactose monohydrate (LAC),water soluble starch (STA),trehalose (TRE) and-cyclodextrin(-CD) as excipients.The morphology of NSD powders was investigated using scanning electron microscope.The particle size and its distribution were determined by laser diffraction with dry dispenser.In vitro deposition performance and emitted dose of NSD powders were determined by a new generation of impactor (NGI).Results:The LAC-1 NSD powders demonstrated exact spherical shapes with smooth surface and strong adhesion,and the yield and volume average diameter were 12.184 μm and 77.7％,respectively.The powders generated a poor aerosolization performance with the emitted dose (ED)and fine particle fraction (FPF,＜ 4.46 μm) of only 78.9％ w/w and 11.2％,respectively.However,the STA-,TRE-and-CD-modified NSD powders showed wrinkled surfaces with volume average diameters of 2.2 ～ 2.4 μm and yields of 80.1％～81.6％.Unsurprisingly,these types of NSD powders demonstrated amazing EDs of 90％～ 93％ and remarkably augmented FPFs of 40％～47％.Conclusion:NSD technology may improve the recovery of powders and obtain powders with smaller aerodynamic diameter,suggesting that NSD is a powerful technique to prepare respirable powders for efficient pulmonary drug delivery.