Numerical evaluation of spray position for improved nasal drug delivery.

For sinus diseases, targeted delivery at diseased sinonasal sites is essential to improve efficacy of topical sprays as a nasal therapeutic. Considering that ostiomeatal complex (OMC) is the mucociliary drainage pathway and airflow exchange corridor between the main airway and the frontal, maxillary, and anterior ethmoid sinuses, we have identified sprayer techniques that are more effective in targeting OMC, along with the sinus cavities. Nasal airflow and drug transport were numerically simulated in five CT-based sinonasal airway reconstructions, drawn from pre-operative chronic rhinosinusitis patients. In each digital model, we applied two different spray orientations at 5-mm insertion: (a) package insert-based direction - an upright spray axis with subject-head inclined slightly forward (22.5 degrees), (b) line-of-sight (LoS) - with spray axis directed at OMC and through centroid of visible OMC's projection on the view-plane for best OMC-sighting. LoS protocol registered an average 8-fold higher targeted delivery, with the finding supported (p 0.85. Finally, observational LoS scores, based on how much of OMC was visible from nostrils, correlated well with the ratio of the projected area of the OMC on the nostril plane to the area of the nostril plane itself.These CFD-based findings can eventually translate to new personalized spray usage instructions, to be recommended by physicians to individual patients during clinic visits