Experimental and numerical analysis of nasal spray drug delivery system
Creators: name: Tong, Xuwen
Publisher: name: RMIT University
Year: 2024
Subjects: classificationCode: 400303
subject: Biomechanical engineering
classificationCode: 401706
subject: Numerical modelling and mechanical characterisation

description: Nasal spray, as an alternative drug delivery method rather than oral medication approach, can solve the formulation break-down in the digestive system and the detox within the liver system. Moreover, human airway drug delivery method has a better level of patient compliance in comparison with the intravenous methods, especially among children. In order to improve the performance of the nasal spray, it is necessary to investigate the external characteristics of atomized particles from these pharmaceutical spray devices. However, the studies for low pressure applications are left barely touched. Owing to the narrow passage structure, it is not feasible to conduct accurate in vivo experiment regarding particle deposition study. Meanwhile in vitro experiment can magnify the tiny nasal cavity for a better visualization, but with some drawbacks that can affect the accuracy of experimental outcome. Therefore, CFD simulation helps to solve this puzzle, however literature research found out that the previous studies neglect the initial particle characteristics.<br><br>In this thesis, the detailed external characteristics of atomized particles after atomization for low pressure conditions are presented. Two commercial pharmaceutical spray devices were tested with different methods. The experiments were performed in three stages. The first stage was to mimic the real human actuation parameters by using lab equipment. The second stage was to capture the outline and break-up length of the spray cone during the fully developed stage and within the region between the nozzle and first break-up length. High Speed Camera (HSC) and spotlight were adopted to obtain the required data. The third stage was to study the droplet size and velocity distributions by using particle image velocimetry (PIV) and particle/droplet image analysis (PDIA). Furthermore, all these realistic results, gained from experimental study, were derived to form the boundary conditions, to be applied in the numerical study via CFD simulation for the first time.<br><br>In the numerical study of this thesis, the conventional and a newly designed device were compared regarding the deposition fraction and the penetration depth. For the conventional device, laminar and turbulent flows were used under the inhalation rate of 15 L/min and two spray cones with four different particle sizes were utilised. In the parametric study of this thesis, the spray alignment was included. Three different spray directions were chosen to compare, where the middle direction was set as the reference. For the newly designed one, similar methodology and procedure was performed, but with a down scaled set of considerations and a new visualization technique. One device was used with both laminar and turbulent flows and four different sized particles. Since the particles deposited in both left and right chambers, the UV-unwrapping technique was adopted for better visualization. After conducting the comparison study, two sets of optimal spray parameters were drawn for each generation of the nasal spray device. Simultaneously, the newly designed device, claimed with noticeable advantages if compared to the conventional devices, was examined in terms of deposition fraction and the relative particle penetration depth in the middle lateral region.