The Way to Spray: Modeling Nasal Spray Deposition
Mahtani, Amrita; Mendoza, Guilly; Yang, Weilin; Zhou, Robin
Intranasal drug delivery is an alternative method in addition to traditional oral and intravenous doses. Nasal drug delivery has proven to be a very effective technique for nicotine cessation (Hjalmarson et al., 1994), the influenza vaccine (Jackson et al. 1999), and drugs that need to be take continuously, such as insulin (Dondeti et al., 1995). Studies have found that for effective fast-acting body response, the drug needs to be deposited in the highly vascularized mucosal tissue lining the bony turbinates in the nasal cavity. Commercial nasal sprays are continuously optimizing parameters to develop the most effective deposition patterns. In this project, drug deposition is modeled using a simplified 2D depiction of the nasal passageway with uniformly-shaped, spherical spray particles. This problem is implemented in COMSOL by using 2D Navier Stokes fluid flow equations to model the airflow through the nose, and the Particle Tracing module to model the spray trajectory and deposition. The model output was validated by determining the percentages of particles in each region of the nasal passage - anterior, turbinate, posterior, and outlet - and comparing with published experimental data by Cheng et al (2001). A sensitivity analysis was done on the following parameters: particle density, particle size, nozzle spray angle, and nozzle penetration depth. It was found that this model was sensitive to only penetration depth. As penetration depth through the nostril increased, there was a decrease in the particle deposition in the anterior region of the nasal cavity and an increase in the percentage of particles that exited through the outlet. Deposition in the middle and posterior regions was not affected by variation in penetration depth. Our sensitivity analysis demonstrated that variations in spray angle, particle size, and density of the nasal spray fluid do not significantly affect deposition pattern. Therefore, when designing nasal sprays, as long as these parameters remain within the specified ranges, consistent deposition patterns will be achieved. This result also allows for further research on creating sprays that are more concentrated and have encapsulated drugs.
BEE 4530 Project
intranasal spray; particle deposition; drug delivery