Designing aerosol size distribution to minimize inter-subject variability of alveolar deposition

• Published in: Journal of aerosol science Vol. 101; pp. 144 - 155
• Main Authors: Karthiga Devi, S.G., Panchagnula, Mahesh V., Alladi, Mohan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-11-2016
• Subjects: Deposition concentration; Inter-subject variability; Polydisperse aerosol; Sensitivity analysis; Sensitivity analysis; Polydisperse aerosol; Deposition concentration; Inter-subject variability
• ISSN: 0021-8502; 1879-1964
• DOI: 10.1016/j.jaerosci.2016.08.005

Lung morphometry has a great influence on the transport and deposition of therapeutic aerosols as well as disease causing micro-organisms. This study aims to establish the relation between aerosol deposition in the alveolar region and parameters determining the lung morphometry. Inter-subject variability in morphometry has been shown to be a cause of poor dosage control in pulmonary drug delivery systems. We employ a computational approach in this study to study the possibility of engineering an aerosol size distribution to minimize the effect of inter-subject variability. The human respiratory system is idealized as a one-dimensional tract, whose cross-section increases as the distance from the trachea increases. The transport of the aerosol is facilitated by inhalation induced alveolar expansion. The numerical model consists of a mass balance equation for the aerosol transport which is coupled with sub-models for deposition by impaction, sedimentation and diffusion. The model has been validated using experimental data from literature on total particle deposition as well as alveolar deposition over a wide range of particle sizes. From the sensitivity analysis it is concluded that distal airway dimensions play a major role in controlling alveolar deposition. For the parametric conditions investigated, model predictions also suggest that particle sizes near 0.01µm and 10µm will result in the least inter-subject variation in alveolar deposition. Finally, we show that total deposition data are not good indicators of subject-to-subject alveolar dosage variation.
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•Inter-subject variability in alveolar lung deposition has been studied by varying the morphometric parameters of the lung.•Aerosol of sizes 0.01µm and 10µm show the least sensitivity to changes in lung morphometry.•Total deposition data cannot be a tool to access inter-subject variability.