title: Transport and deposition of pharmaceutical particles in three commercial spacer-MDI combinations.
abstract: Respiratory drug delivery has been under the research spotlight for the past few decades, mainly due to the high incidence of pulmonary diseases and the fact that this type of delivery offers the highest efficiency for treatment. Despite its invaluable benefits, there are some major drawbacks to respiratory drug delivery, the most important of which being poor delivery efficiency and relatively high drug deposition in undesirable regions, such as the mouth cavity. One way to improve the efficiency of respiratory drug delivery with metered-dose inhalers is placing a respiratory spacer between the inhaler exit and the mouth. It is argued that high drug deposition in the immediate airways of the respiratory system is strongly affected by relatively high initial momentum of pharmaceutical particles leaving the inhaler. A respiratory spacer, however, can provide an expansion region in which the initial momentum of particles can subside. As a result, particles enter the patient׳s oral cavity more gradually and are more likely to reach the desired regions. In this study, the effectiveness of using three commercial spacers paired with a commercial inhaler is examined through numerical investigation of fluid flow and particle transport phenomena. Particles ranging from 1 to 50 µm in diameter are tracked using a Lagrangian point of view and fluid flow fields are resolved using the LRN k-ω turbulence model. A novel particle injection method is introduced and is demonstrated to be able to adequately capture the effects of particle initial momentum. Lastly, a few design suggestions are made.
authors.affiliation: Center of Excellence in Energy Conversion (CEEC), School of Mechanical Engineering, Sharif University of Technology, P.O. Box 11155-9567, Tehran, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Yazdani
authors.affiliation: Center of Excellence in Energy Conversion (CEEC), School of Mechanical Engineering, Sharif University of Technology, P.O. Box 11155-9567, Tehran, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Normandie
authors.affiliation: Micro-Nano Research Facility, RMIT University, Melbourne, Victoria 3001, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Yousefi
authors.affiliation: Center of Excellence in Energy Conversion (CEEC), School of Mechanical Engineering, Sharif University of Technology, P.O. Box 11155-9567, Tehran, Iran. Electronic address: mssaidi@sharif.edu.
authors.forename: M S
authors.initials: MS
authors.lastname: Saidi
authors.affiliation: Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY 13699-5725, USA.
authors.forename: G
authors.initials: G
authors.lastname: Ahmadi
mesh_terms: D000280:Administration, Inhalation; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D036501:Metered Dose Inhalers; D008962:Models, Theoretical; D019141:Respiratory System Agents / Q000008:administration & dosage* / Q000737:chemistry*; D012212:Rheology / Q000379:methods*
chemical_list: D019141:Respiratory System Agents
keywords: Lagrangian particle tracking; Metered-dose inhaler; Pharmaceutical particles; Respiratory drug delivery; Respiratory spacer