Airway deposition of two fixed-dose triple combination pMDI drugs at different inhalation flow rates and insertion...

The objective of this study was to establish a robust experimental and computational framework for characterizing pressurized metered-dose inhaler (pMDI) plumes and quantifying regional deposition fractions of two triple-combination aerosol drugs, Trimbow® (BDP/GLY/FF) and Trixeo Aerosphere® (BUD/GLY/FF). Specifically, we investigated the influence of inhalation flow rate and inhaler insertion angle on whole-airway and regional drug deposition. To achieve this, laser-based measurement techniques were developed and coupled with advanced image-processing algorithms. Computational fluid and particle dynamics simulations, combined with analytical particle-tracking methods, were employed to model the fate of aerosol particles from inhalation to deposition or exhalation. Results demonstrated efficient lung deposition for both drugs across a wide range of inhalation flow rates. For BDP/GLY/FF, total lung deposition accounted for 32.1%, 39.8%, 41.2%, and 36.1% of the emitted dose at flow rates of 30, 60, 90, and 120 L/min, respectively. Corresponding deposition fractions for BUD/GLY/FF were 31.9%, 43.0%, 44.0%, and 38.9%. Regional analysis revealed that BDP/GLY/FF exhibited comparable deposition in the first eight bronchial generations (large bronchi) and in the distal airways. In contrast, BUD/GLY/FF showed higher deposition (4 to 6 times greater) in the large bronchi compared to deeper regions. Furthermore, inhaler orientation significantly affected deposition outcomes. A slightly upward mouthpiece insertion enhanced lung deposition, whereas a downward orientation reduced it compared to horizontal positioning. These findings underscore the importance of inhalation technique and device orientation in optimizing therapeutic efficacy of pMDI-delivered triple-combination drugs.