Costas Kiparissides, Aleck Alexopoulos and Jovana Milenkovic

Department of Chemical Engineering, Aristotle University of Thessaloniki, PO Box 472, 54124, Thessaloniki, Greece

Abstract:

Dry Powder Inhalers, DPIs, are a principle means of delivering pharmaceuticals via the respiratory system due to their ease of use and cost-effectiveness. The main function of a DPI device is the adequate dispersion and delivery of particles initially in the form of a loose powder. In the first part of the paper, the steady-state and dynamic flow in a commercial DPI device (i.e., Turbuhaler) is analysed during the inhalation cycle. The DPI geometry is constructed in a CAD/CAM environment (i.e., CATIA v5) and then imported into GAMBIT for the construction of a tetrahedral cells grid. The Navier-Stokes equations are solved using FLUENT (v6.3). Particle motion and deposition are described using an Eulerian/Lagrangian approach. In the second part of the paper, the investigation of airflow in the pulmonary tract as well as the analysis of particle motion and deposition of micro- and nano-particles in the lungs is carried out. Realistic flow models are applied to subsets of the pulmonary tract extending from the bronchi to the alveoli (e.g., a series of branches or branch blocks) to describe steady-state flow and particle deposition. Steady-state flow in the respiratory tract is described using a sequential computational block technique. Dynamic flow simulations are also considered by imposing a time-varying exit pressure in each computational block.

This combined DPI/respiratory tract approach can elucidate the connection between the DPI device operating parameters and particle properties and deposition profiles in the respiratory tract.