Abstract

The marketed dry powder inhalations (DPI) are based on lactose monohydrate alone and lactose anhydrous is neither studied nor used as a carrier in marketed DPIs. Lactose is not recommended as a carrier in budesonide formulations since lactose interacts with amine functional group. This study was carried out to investigate the effect of lactose anhydrous inhalation grade 40 M on the aerosolisation performance of budesonide. The work was also aimed at study of an interaction between budesonide and the lactose carriers in dry state. The powder properties of binary formulations, consisting of lactose anhydrous LA 40M and budesonide, were compared with those of lactose monohydrate LM 40 M and budesonide. In vitro drug release was determined with diffusion cell. Based on the results of the preliminary study, two promising formulations F1 and F2 were subjected to the in vitro deposition study using Twin Stage Impinger and Lupihaler®. The results revealed absence of chemical reaction between budesonide and both the grades of lactose namely, LM and LA. Hence lactose can be used as a carrier in budesonide dry powder formulations. The aerosolisation performance of DPIs, consisting of either lactose monohydrate 40M or lactose anhydrous 40M, was similar. The particle size distribution, particle density, morphology, surface roughness, flowability and moisture content of lactose carriers played a complex role in determining fine respirable fraction of budesonide. The in vitro deposition profile of budesonide was improved significantly when budesonide was blended with LM 40M or LA 40M in 1:45 ratio.

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