Experimental measurements of particle deposition in the human nasal airway.

Abstract

Intranasal drug delivery is a promising non-invasive method for administering both local and systemic medications. While previous studies have extensively investigated the effects of particle size, airflow dynamics, and deposition locations on deposition efficiency, they have not focused on the thickness of deposited particles, which can significantly affect drug dissolution, absorption and therapeutic efficacy. This study investigates the deposition patterns of dry powder particles within the nasal airway, specifically examining how factors such as flow rates, particle size, and particle cohesiveness influence deposition patterns and their thickness. Using optical coherence tomography (OCT), this study assessed the deposition behaviour of three different lactose powders in a reconstructed nasal airway model at three key anatomical locations under varying flow rates (15, 35 and 55 L/min). Computational fluid dynamics (CFD) simulations were conducted to complement the experimental data, demonstrating the airflow dynamics in the nasal airway and highlighting recirculation zones that impact deposition patterns. The results revealed that the anterior section of the nasal airway is particularly effective at capturing particles, with localised flow patterns playing a critical role in particle accumulation. These flow patterns, combined with particle size and cohesiveness, are key factors in determining where and how particles cluster, leading to thicker deposition in specific areas of the nasal airway. This study addresses the gap in understanding how these factors influence deposition thickness and spatial distribution, ultimately contributing to the optimisation of nasal drug delivery systems.