Supplementary data for "Mechanics-guided parametric modeling of intranasal spray devices and formulations for targeted drug delivery to the nasopharynx"

Improving the performance of nasal sprays through optimization of key device and formulation parameters, such as the formulation density, spray cone angle, and sprayed droplet sizes—is hypothesized to be an effective strategy to enhance deposition efficiency at target tissue sites along the airway, marked for their proclivity for the initial onset of infection. This study identifies the nasopharynx, a primary locus of early viral entry, as the optimal target for intranasal drug delivery. Three-dimensional anatomical geometries reconstructed from high-resolution computed tomography scans were employed to evaluate a cone injection approach, considering monodispersed sprayed particle sizes between 10 – 50 μm, six formulation densities ranging from 1.0 – 1.5 g/ml, and twelve plume angles spanning 15^◦ – 70^◦. Large Eddy Simulation mimicking the inhaled airflow within the anatomical domains was coupled with a Lagrangian particle-tracking framework to derive the drug deposition trend. The resulting three-dimensional deposition contour map revealed that nasopharyngeal deposition was maximized for droplet sizes of 25 – 45 μm and plume angles ≤ 30^◦, when the nasopharyngeal deposition rates are averaged across all the test airway geometries and formulation densities. In addition, the formulation density of 1.0 g/ml yielded the highest mean deposition rate, over the tested range of sprayed particle sizes and plume angles. The findings collectively demonstrate that rational optimization of intranasal spray design is achievable and can substantially enhance targeted drug delivery to the nasopharynx, thereby aiding in the mitigation of airway diseases.