Effects of the deformation and size of the upper airway on the deposition of aerosols

Dazhao Gou; Qixuan Zhu; Hak-Kim Chan; Agisilaos Kourmatzis; Shaokoon Cheng; Runyu Yang

doi:10.1016/j.ijpharm.2024.124165

Effects of the deformation and size of the upper airway on the deposition of aerosols

Int J Pharm. 2024 Apr 24:657:124165. doi: 10.1016/j.ijpharm.2024.124165. Online ahead of print.

Authors

Dazhao Gou¹, Qixuan Zhu¹, Hak-Kim Chan², Agisilaos Kourmatzis³, Shaokoon Cheng⁴, Runyu Yang⁵

Affiliations

¹ School of Materials Science and Engineering, UNSW Sydney, NSW 2052, Australia.
² Advanced Drug Delivery Group, Sydney Pharmacy School, The University of Sydney, NSW 2006, Australia.
³ School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006, Australia.
⁴ School of Engineering, Macquarie University, NSW 2109, Australia.
⁵ School of Materials Science and Engineering, UNSW Sydney, NSW 2052, Australia. Electronic address: r.yang@unsw.edu.au.

PMID: 38663643
DOI: 10.1016/j.ijpharm.2024.124165

Abstract

Aerosol drug delivery in the human airway is significantly affected by the morphology and size of the airway. This work developed a CFD-DEM model to simulate and analyze air flow and powder dynamics in combined inhaler-airway systems with different degrees of airway deformation (non-deformed, 50%, and 75% deformed) and sizes (adult, 0.80, and 0.62 scaled). The airways were generated based on a regular airway constructed from the MRI images through finite element method (for deformed airways) or scaling-down (for smaller airways). The airways were connected to Turbuhaler® through a connector. The results showed that under the same flow rate, the variation in the airway geometry and size had a minimum impact on the flow field and powder deposition in the device and the connector. However, deformation caused more particle deposition in the deformed region. Notably, the airway with 50% deformation had the most particles passing through the airway with the largest particle sizes due to its lower air velocity in the deformed area. Reducing airway size resulted in more powder deposition on the airway, particularly at the pharynx and mouth regions. This was because, with the same flow rate, the flow velocity in the smaller airway was higher, causing more particle-wall collisions in the mouth and pharynx regions. More importantly, the deposition efficiency in the 0.62-scaled airway was significantly higher than the other two airways, highlighting the importance of the different administration of aerosol drugs for young children.

Keywords: Airway size; CFD-DEM; Deformation; Dry powder inhalation; Upper airway.