Numerical and Experimental Analysis of Drug Inhalation in Realistic Human Upper Airway Model

Abstract

The demand for a more efficient and targeted method for intranasal drug delivery has led to sophisticated device design, delivery methods, and aerosol properties. Due to the complex nasal geometry and measurement limitations, numerical modeling is an appropriate approach to simulate the airflow, aerosol dispersion, and deposition for the initial assessment of novel methodologies for better drug delivery. In this study, a CT-based, 3D-printed model of a realistic nasal airway was reconstructed, and airflow pressure, velocity, turbulent kinetic energy (TKE), and aerosol deposition patterns were simultaneously investigated. Different inhalation flowrates (5, 10, 15, 30, and 45 L/min) and aerosol sizes (1, 1.5, 2.5, 3, 6, 15, and 30 µm) were simulated using laminar and SST viscous models, with the results compared and verified by experimental data. The results revealed that from the vestibule to the nasopharynx, the pressure drop was negligible for flow rates of 5, 10, and 15 L/min, while for flow rates of 30 and 40 L/min, a considerable pressure drop was observed by approximately 14 and 10%, respectively. However, from the nasopharynx and trachea, this reduction was approximately 70%. The aerosol deposition fraction alongside the nasal cavities and upper airway showed a significant difference in pattern, dependent on particle size. More than 90% of the initiated particles were deposited in the anterior region, while just under 20% of the injected ultrafine particles were deposited in this area. The turbulent and laminar models showed slightly different values for the deposition fraction and efficiency of drug delivery for ultrafine particles (about 5%); however, the deposition pattern for ultrafine particles was very different.

Computational Rhinology: Unraveling Discrepancies between In Silico and In Vivo Nasal Airflow Assessments for Enhanced Clinical Decision Support

“…Aasgrav et al [3] showed that laminar and RANS CFD models produced similar results. The conclusion has been supported by many researchers including, e.g., Larimi et al [199], who reported negligible turbulence intensity in the nasal cavity for normal, inspiratory breathing rates, and Schillaci and Quadrio [148] and Bradshaw et al [159], who reported mostly laminar flow for normal resting breathing conditions.…”

“…Also, the current paper does not review the extensive scientific literature concerning FSI, acoustic phenomena, or particle transport and deposition, in human airways. Recent literature overviews on these topics were provided by Ashraf et al [ 107 ] and Le et al [ 197 ] for FSI, Xi et al [ 198 ] for acoustics, and Larimi et al [ 199 ] for particle deposition.…”

Physical Conditions Prevailing in the Nasal and Maxillary Sinus Cavities Based on Numerical Simulation

“…Measurements based on computational fluid dynamics (CFD) have been the subject of studies demonstrating the method’s effectiveness [ 8 , 9 , 10 , 11 ]. Numerical analysis has been used in various studies such as airflow diagnostics in patients with sleep apnoea, deposition fraction, and drug delivery efficiency [ 12 , 13 ]. Recent research has confirmed that the use of numerical modelling to analyse airflow through the nasal cavity (virtual rhinomanometry) can be considered a reliable method [ 14 ].…”

Computational Human Nasal Reconstruction Based on Facial Landmarks

“…Through the digital model, the analysis and computation of parameters such as pressure, velocity, and turbulent kinetic energy (TKE) can be compared with other models. Additionally, the study [20] showed that there was tissue displacement and hypoplasia for patients with cleft lip repair. Therefore, the authors proposed 3Dprinted autologous cartilage rhinoplasty to reconstruct the nasal shape.…”