The impact of flow rate on inhaler dose delivery from a dry powder inhaler using a two stage impinger

Abstract EN

The purpose of this study is to investigate the effect of various flow rates and morphology of spray-dried transferosomes depending on the amount of drug delivered in “respirable” fractions from a monodose dry powder inhaler (DPI).

A two-stage impinger (TSI) was used to investigate the deposition of salbutamol sulphate (SS) as a model drug incorporated within four different carrier-based transferosomes (sorbitol, inulin, trehalose and maltodextrin).

The amount of drug was collected from each stage of the TSI, as well as the device and capsule at three different flow rates: 30, 60 and 90 L/min, and subsequently quantified by high performance liquid chromatography (HPLC).

Results from this study showed that the 30L/min flow rate was not as effective as 60L/min or 90L/min at delivering drug to the lower stage of the TSI.

However, 90L/min flow rate had a higher drug deposition in the lower impinger when compared to 60L/min.

Sorbitol was found to be the least effective carrier at delivering drug to the lower chamber of the TSI, followed by maltodextrin, whereas trehalose and inulin were more spherical and smaller in size and were found to be the most effective carrier systems in the spray-dried formulations.

In conclusion, trehalose and inulin-based transferosomes were the most effective delivery system for depositing the drug into the lower part of two stage impinger.