Biomechanical study of particle deposition in the nasal and nasopharyngeal cavities of healthy subjects

Abstract

To build a finite element numerical model of the nasal and nasopharyngeal cavities in healthy subjects and analyze the particle deposition characteristics of the nasal and nasopharyngeal cavities under different conditions, in order to investigate the influencing factors of particle deposition in the nasal and nasopharyngeal cavities of healthy subjects from the perspective of biomechanics, and to provide reference for the potential predisposing factors of clinical nasal and nasopharyngeal diseases and transnasal drug delivery methods. The nasal multi-layer spiral CT data of a healthy adult male volunteer was collected, and a three-dimensional numerical model was reconstructed based on the obtained image data (the model included nasal cavity, nasopharyngeal cavity, and pharyngeal cavity), and then numerical simulations were performed for particle deposition under different airflow rate, particle size and particle density conditions. In the reconstructed model, the nasal threshold, the nasal vestibule, the anterior part of the inferior and middle turbinates, and the posterior wall of the nasopharyngeal apex are the most likely areas for particle settling. When the airflow rate was 30L/min and 60L/min, the deposition efficiency(DE) of the reconstructed model was more than 80% with different particle diameters and particle densities. When the particle diameter is 10um and 15um, the deposition efficiency of the reconstructed model can reach more than 90% under different airflow rate and particle density. When the particle density and airflow rate were constant, the deposition efficiency of particles in the posterior wall of the nasopharynx decreased as the particle diameter became larger. A numerical model of nasal and nasopharyngeal cavity biomechanics can be established to explore the important influencing factors of particle deposition in the nasal and nasopharyngeal cavities from a biomechanical perspective. It was found that: 1. particle deposition mainly at the nasal threshold and nasal vestibule in the nasal cavity, and mainly at the posterior wall of the nasopharyngeal apex in the nasopharyngeal cavity; 2. airflow velocity, particle size and density all had effects on particle deposition rate, among which particle size had the greatest effect on particle deposition, followed by airflow rate, and the effect of particle density changes on particle deposition was not significant; 3. when particle density and airflow rate were constant, the smaller the particle diameter, the the more particle deposition in the nasopharyngeal cavity, the larger the particle diameter, the more particle deposition increases in the anterior part of the nasal cavity, and the less particle deposition in the nasopharyngeal cavity; 4. As the particle diameter increases, the particle deposition in this reconstructed model increases.

Modeling brain pathology to study nose-to-brain drug delivery

“…However, it remains undisputed that the intranasal administration shortens the delivery time owing to the direct transport through the ethmoid bone (1). The mucosal surface area of each nasal passage ranges from 0.15 m 2 to 0.22 m 2 and has been found to be most effective at low drug dose concentrations, with a simple route of administration and high patient compliance (2).…”