Intranasal Spray Characteristics for Best Drug Delivery in Patients With Chronic Rhinosinusitis

Abstract

Objectives: To determine parameter combinations for effective drug delivery of intranasal spray steroids to the ostiomeatal complex (OMC) and maxillary sinus (MS) in patients with chronic rhinosinusitis (CRS).

Methods: Each patient's sinonasal cavity was reconstructed from computed tomography scans. Intranasal airflow and drug particle transport were simulated using computational fluid dynamic modeling. Airflow simulations were performed at 15 Pascal inhalation pressure. Intranasal spray particles of 1-100 μm were simulated at release speeds of 1, 5, and 10 m/s from 6 release locations (Bottom, Center, Top, Lateral, Lateral-Bottom, and Lateral-Top) at a nozzle insertion depth of 15 mm. Drug delivery simulations were performed in the head tilted forward position.

Results: Maximal OMC deposition was 0.78%-12.44%, while maximal MS deposition was 0.02%-1.03% across all simulations. In general, particles between 6 and 10 μm had the best OMC (at 1 m/s particle velocity) and MS (at 10 m/s particle velocity) deposition. Particles ranging from 21 to 30 μm also had superior OMC deposition. The lateral and lateral-top spray release locations produced maximum OMC deposition, but no one release location demonstrated an increase in MS deposition.

Conclusion: This preliminary study suggests that it is challenging to determine a common set of intranasal spray parameter combinations for effective drug delivery to the OMC and MSs. Although drug particle size and spray particle velocity seem to impact particle deposition patterns, spray release location appears to vary with anatomical differences between subjects, particularly when the MS is the target location for particle deposition. Laryngoscope, 133:1036-1043, 2023.

Keywords: chronic rhinosinusitis; computational fluid dynamics; drug delivery.

Figure 1.

Coronal views from CT scans of all patients. A. Subject 1, B. Subject 2, C. Subject 3, D. Subject 4, E. Subject 5. F. Schematic diagram of the sinonasal airway.

Figure 2.

Drug particle deposition on each side in A. MS, and B. OMC

Figure 3.

Particle deposition in the paranasal airway by release location.

Figure 4.

Deposition by particle size group. A. Subject 1 MS, B. Subject 1 OMC, C. Subject 2 MS, D. Subject 2 OMC. (G01=1–5 microns, G02=6–10 microns, G03=11–20 microns, G04=21–30 microns, G05=31–40 microns, G06=41–50 microns, G07=51–60 microns, G08=61–70 microns, G09=71–80 microns, G10=81–90 microns, G11=91–100 microns)

Figure 5.

Deposition by particle size group. A. Subject 3 OMC, B. Subject 5 OMC, C. Subject 4 MS, D. Subject 4 OMC. Note Subjects 3 and 5 had zero MS deposition and were not displayed on the plot. (G01=1–5 microns, G02=6–10 microns, G03=11–20 microns, G04=21–30 microns, G05=31–40 microns, G06=41–50 microns, G07=51–60 microns, G08=61–70 microns, G09=71–80 microns, G10=81–90 microns, G11=91–100 microns)