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Development of an Idealized Nasal Geometry for Estimation of Regional Deposition of Nasal Sprays

Finlay WH, Chen J, Kiaee M, Martin AR.

Respiratory Drug Delivery 2021. Volume , 2021: 127-134.

Abstract:

Delivery of therapeutic agents via nasal sprays is influenced by a large number of factors. As a result, in vitro testing is often used to guide research and development of nasal spray products. The use of a realistic nasal replica, typically 3D printed using measurements from computed tomography (CT) scans, allows benchtop parameter exploration for a given single subject. An alternative approach is to develop an idealized nasal geometry that replicates average deposition for a population of subjects. To this end, we simulated the fluid dynamics and particle motion over a wide range of parameter values in seven realistic replicas obtained from CT scans of human subjects. This large computational fluid dynamics (CFD) dataset was then used to develop an idealized nasal geometry that replicated average regional deposition over the range of this dataset. The resulting idealized geometry was manufactured using rapid prototyping, and in vitro regional deposition in the idealized geometry compared to that measured in five realistic replicas using NasalCrom® nasal spray, as well as to previously published regional deposition seen in vivo using gamma scintigraphy in five subjects. Good agreement was found, indicating that the present idealized nasal geometry behaves as intended.