Parametric numerical analysis of targeted drug delivery for intranasal sprays inside the upper respiratory airspace

Efficient drug delivery to clinical target sites along the upper airway strongly depends on variables associated with the delivery device and the drug solution, e.g., the device plume angle and the formulation density. Our study considers the nasopharynx, which is the main initial viral infection site, and the ostiomeatal complex (OMC), which is the common drainage pathway for sinus inflammations, as the preferred target zones for drug delivery. We have used Large Eddy Simulation and Lagrangian techniques to replicate breathing at 15 L/min and quantify regional drug deposition; the latter as a function of the device plume angle and the formulation material density. Three anatomic nasal geometries are being studied with conically injected spray droplet sizes of 10–50 microns, while the formulation density is varying between 1100–1500 kg/m³ and the plume angles are 15–70 degrees. The results comprise novel 3D surface maps (for each formulation density) with plume angles and particle size distributions along the horizontal plane and regional deposition (at nasopharynx and OMC) along vertical axis. Sample findings show that nasopharyngeal deposition peaks for particle diameters 15–25 microns for plume angles < 20 degrees.