Non Uniform Deposition of pMDI Aerosol in a Large Volume Spacer

Chronic lower respiratory tract diseases have been cited as the fourth leading cause of death in Canada in both 2000 and 2009 [1]. Pressurised metered dose inhalers (pMDIs) administer medication for patients suffering from these disorders, in particular for asthma. Medication released from a pMDI can be difficult to inhale directly, and add-on devices have been designed to aid delivery. While add-on devices, or spacers, increase the percentage of medication that reaches the patient, medication also deposits on the walls of the device. The deposition of medication within a large volume spacer is studied, using spectrophotometry for experiments and computational fluid dynamics, implementing mean-flow and turbulent tracking of particles. Regions of deposition are of interest, as well as the way that the deposition varied for different inhalation flow rates. The aim is to determine optimal inhalation flow rate as well as studying the cause of the non-symmetrical deposition.