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Subject-Specific Whole-Lung CFPD Coupled with PBPK/PD to Predict Inhaled Bronchodilator Response in Asthmatic and Healthy Subjects
Journal article   Open access   Peer reviewed

Subject-Specific Whole-Lung CFPD Coupled with PBPK/PD to Predict Inhaled Bronchodilator Response in Asthmatic and Healthy Subjects

Prathish K. Rajaraman, Xuan Zhang, Alejandro P. Comellas, Eric A. Hoffman and Ching-Long Lin
Journal of aerosol science, Vol.194, 106784
05/2026
DOI: 10.1016/j.jaerosci.2026.106784
url
https://doi.org/10.1016/j.jaerosci.2026.106784View
Published (Version of record) Open Access

Abstract

Accurate prediction of bronchodilator performance remains challenging. We present a coupled computational fluid and particle dynamics (CFPD) and physiologically-based pharmacokinetic /pharmacodynamics (PBPK/PD) framework that leverages subject-specific CT-derived airway trees and airflow distributions to model regional lung exposure and the resulting clinical effect, quantified as the change in Forced Expiratory Volume in 1 second (ΔFEV1). Data from six asthmatic and ten healthy subjects were analyzed. CFPD simulations predicted subject-specific airflow and drug deposition by airway generation for inhalation of 400 μg albuterol using a metered dose inhaler (MDI) and a dry powder inhaler (DPI). The deposited dose was input into the PBPK model at the epithelial lining fluid (ELF) to predict drug concentrations in plasma and tissues. The PD model predicted ΔFEV1 at the subepithelium effect-site. Two key observations emerged. First, MDI use shifted the inhaled dose toward the respiratory region, whereas DPI delivery resulted in greater deposition in generations G2-G5. Second, asthmatic subjects exhibited higher resistance than healthy subjects in generations G5-G10, resulting in larger ΔFEV1. Fitted PD model parameters, yielded a half-maximal effective concentration (EC50 =1.1±0.07 nM) and Hill slope (n =1.6±0.1), with R2 = 0.98. In summary, we developed a subject-specific coupled CFPD-PBPK/PD framework to predict inhaled albuterol exposure in plasma and ELF, as well as the resulting ΔFEV1 clinical response. This approach has the potential to inform inhaler selection, optimize dosing strategies, and enable disease-specific inhalational therapies. The present study was limited to male subjects, and future work should extend the framework to include sex-specific physiological differences. •Albuterol transport and deposition were simulated in imaging-based subject-specific asthmatic and healthy airways.•Plasma and subepithelial albuterol concentrations were predicted across subject cohorts.•MDI shifts dose to the respiratory zone, whereas DPI deposits more in proximal conducting airways.•Subepithelial effect-site concentrations in generations G5-G10 closely matched observed ΔFEV1.
Albuterol Computational Fluid-Particle Dynamics (CFPD) Drug deposition Dry Powder Inhaler (DPI) Metered Dose Inhaler (MDI) Pharmacodynamics (PD) Pharmacokinetic (PK)

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