High Resolution Visualization and Analysis of Nasal Spray Drug Delivery

Purpose: Effective nasal drug delivery of new-generation systemic drugs requires efficient devices that can achieve targeted drug delivery. It has been established that droplet size, spray plume, and droplet velocity are major contributors to drug deposition. Continual effort is needed to better understand and characterise the physical mechanisms underpinning droplet formation from nasal spray devices. Methods: High speed laser photography combined with an in-house designed automated actuation system, and a highly precise traversing unit, measurements and images magnified in small field-of-view regions within the spray was performed. Results: The qualitative results showed a swirling liquid sheet at the near-nozzle region as the liquid is discharged before ligaments of fluid are separated off the liquid sheet. Droplets are formed and continue to deform as they travel downstream at velocities of up to 20 m/s. Increase in actuation pressure produces more rapid atomization and discharge time where finer droplets are produced. Conclusions: The results suggest that device designs should consider reducing droplet inertia to penetrate the nasal valve region, but find a way to deposit in the main nasal passage and not escape through to the lungs.