AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Transient Deposition Functions Applicable to Inhaled Pharmaceutical Aerosols
Philip Ophus, CARLOS LANGE, University of Alberta
Abstract Number: 602 Working Group: Health Related Aerosols
Abstract Single breath devices, which have strong transient effects, are becoming more common in the delivery of aerosol medications. Most current mathematical functions used to predict the deposition of inhaled aerosol particles in the human lung are based on Lagrangian models of particle flow. These models work well for certain particle effects that occur during respiration, but they are ill-suited for modelling instantaneous time-dependent effects. The alternative to Lagrangian models is Eulerian models, which can handle transient effects much more easily, though they are difficult to create. Deposition functions truly based on Eulerian models are needed to accurately simulate the short-term single-breath effects of a typical breathing pattern and thus provide better dosage estimates.
In the interest of developing such Eulerian deposition models, mathematical techniques were employed to develop fully time-dependent Eulerian deposition functions. These methods were used to describe the velocity fields of simple particle flows. Analytic expressions describing the time-dependent flow of particles through a curved pipe were created and solved numerically. The results compared well with classical analytical and experimental results for the steady-state case. Numerical simulations with the new functions were used to determine which flow regimes required the use of Eulerian modelling for deposition prediction. Solutions to simple cases such as this will provide the functional form for more complicated geometries and flows, such as that in the mouth/throat region or the flow past a bifurcation in the lung pathways.