Simulation of the Performance of a Dry Powder Inhaler Using Computational Fluid Dynamics
Rapid development in inhalation drug delivery over the past decade has led to the invention of a wide range of innovative dry powder inhaler systems. One such commercially available device is the Aerolizer, which utilises a spinning capsule for powder dispersion. Upon inhalation, the air flow entering the inhaler through the tangential air inlets acts to rotate the capsule at high speed, ejecting the drug powder into the surrounding flowfield. The de-agglomerating forces required to disperse the drug agglomerates are provided by the air flowfield generated within the device. However there is a distinct lack of knowledge in the literature examining how the flowfield generated in dry powder inhalers interacts with the drug agglomerates to generate respirable aerosol clouds. This thesis aims to address this by combining computational fluid dynamics (CFD) with experimental powder dispersion analysis to develop tools to examine the fundamental factors affecting agglomerate dispersion in a dry powder inhaler, with specific focus on the effects of device design and operating conditions.