In vitro assessment of an idealized nose for nasal spray testing: Comparison with regional deposition in realistic nasal replicas

[Display omitted] An idealized nasal replica that mimics average regional deposition of nasal spray pump droplets in human nasal airways would potentially be useful in expediting the development of nasal spray products. The aim of this study was to validate an idealized nose, previously developed using in silico simulations, by comparing with regional deposition in realistic, sectioned nasal replicas obtained from in vitro deposition experiments. The realistic nasal airway replicas of five subjects obtained from computerized tomography were manufactured in plastic using rapid prototyping. The idealized nose was made using the same build procedure. A commercial nasal spray pump (NasalCrom, 5.2 mg cromolyn sodium per spray) was then actuated repeatably into each replica under a steady inspiratory flow of 7.5 L/min at two different orientations (45° and 60° from the horizontal). Sectioned replicas were disassembled, and the mass fraction of drug deposited on the surface of each anatomical region was determined. It was found that regional deposition of spray droplets in the idealized replica agreed well with average regional deposition in the realistic replicas. Regional deposition also agreed with previously published in vivo regional deposition using the same spray pump.