Abstract

Determine the particle size distribution of drug particles in the binary blend (API-Carrier) of dry powder inhaler formulations is challenging. Direct approaches like Scanning Electron Microscope (SEM) may be used but may not be statistically representative of the larger population. Cascade impaction techniques are typically used to study the aerodynamic particle size of the emitted API but this may not reflect the actual primary particle size used to create the formulation as not all particles are deaggregated or separated from the lactose carrier during testing. In this work, we developed a fast and reproducible method to analyze the particle size distribution (PSD) of an API within binary lactose blends using a modified powder disperser and laser diffraction technique. Our goal was to provide a simple tool to DPIs formulations when the original particle size of the API is unknown.