Effect of temperature and moisture on the uniformity of delivered dose, emitted dose and fine particle fraction for three different DPI formulations

The development of a stable dry powder inhalation (DPI) product with the delivery of consistent fine particle fraction until the product expires is challenging for many drug companies. The main purpose of this study was to investigate the influence of both temperature and humidity on the uniformity of delivered dose, emitted dose and fine particle fraction on three different DPI products in two different packs viz. HDPE container and Alu Alu blister during the stability studies. The study has been performed on Budesonide 400 mcg, Formoterol fumarate dihydrate 12 mcg and Tiotropium bromide 18 mcg DPI products. The uniformity of delivered dose (UDD) is calculated by using the Dosage Unit Sampling Apparatus (DUSA) and the emitted dose (ED) and fine particle fraction (FPF) are calculated by using the Next Generation Impactor (NGI). All three products have shown no significant reductions in the UDD, Formoterol fumarate showed a significant reduction in ED value and all of them showed a significant reduction in the FPF values. The reduction in FPF was more in Alu Alu blisters as compared to HDPE containers.The outcome of the study could be extrapolated to other DPI formulations.