Transport and deposition of hygroscopic particles in asthmatic subjects with and without airway narrowing

Prathish K Rajaraman; Jiwoong Choi; Eric A Hoffman; Patrick T O'Shaughnessy; Sanghun Choi; Renishkumar Delvadia; Andrew Babiskin; Ross Walenga; Ching-Long Lin

doi:10.1016/j.jaerosci.2020.105581

Transport and deposition of hygroscopic particles in asthmatic subjects with and without airway narrowing

J Aerosol Sci. 2020 Aug:146:105581. doi: 10.1016/j.jaerosci.2020.105581. Epub 2020 Apr 28.

Authors

Prathish K Rajaraman^{1

2}, Jiwoong Choi^{1

2}, Eric A Hoffman³, Patrick T O'Shaughnessy⁴, Sanghun Choi⁵, Renishkumar Delvadia⁶, Andrew Babiskin⁶, Ross Walenga⁶, Ching-Long Lin^{1

2}

Affiliations

¹ Department of Mechanical Engineering, The University of Iowa, Iowa City, IA, USA.
² IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, USA.
³ Department of Radiology, The University of Iowa, Iowa City, IA, USA.
⁴ Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA, USA.
⁵ School of Mechanical Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea.
⁶ Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA.

Abstract

This study numerically investigates the effect of hygroscopicity on transport and deposition of particles in severe asthmatic lungs with distinct airway structures. The study human subjects were selected from two imaging-based severe asthmatic clusters with one characterized by non-constricted airways and the other by constricted airways in the lower left lobe (LLL). We compared the deposition fractions of sodium chloride (NaCl) particles with a range of aerodynamic diameters (1-8 μm) in cluster archetypes under conditions with and without hygroscopic growth. The temperature and water vapor distributions in the airways were simulated with an airway wall boundary condition that accounts for variable temperature and water vapor evaporation at the interface between the lumen and the airway surface liquid layer. On average, the deposition fraction increased by about 6% due to hygroscopic particle growth in the cluster subjects with constricted airways, while it increased by only about 0.5% in those with non-constricted airways. The effect of particle growth was most significant for particles with an initial diameter of $2 μm$ in the cluster subjects with constricted airways. The effect diminished with increasing particle size, especially for particles with an initial diameter larger than 4 μm. This suggests the necessity to differentiate asthmatic subjects by cluster in engineering the aerosol size for tailored treatment. Specifically, the treatment of severe asthmatic subjects who have constricted airways with inhalation aerosols may need submicron-sized hygroscopic particles to compensate for particle growth, if one targets for delivering to the peripheral region. These results could potentially inform the choice of particle size for inhalational drug delivery in a cluster-specific manner.

Keywords: Airway constriction; Cluster analysis; Computational fluid dynamics; Hygroscopic growth; Particle deposition.

Abstract

Grants and funding