Particle depositions in multi stage liquid impinger as simplified lung model using computational fluid dynamic

Abstract

Inhaled medication is typically used to treat obstructive pulmonary disease and systemic diseases. The effectiveness of pulmonary drug delivery depends on the amount of drug deposited beyond the oropharyngeal region, the place where the deposition and the uniform distribution occurred. In this study, the performance of multistage liquid impinger (MSLI) simplified model which imitates the physiological lung in delivering the drug was analyzed. In order to achieve this main aim, the airflow patterns and particle depositions efficiency were evaluated in MSLI simplified model using computational fluid dynamic of COMSOL® software. The particle deposition efficiency is studied by varying flowrates (30.0 L/min, 60.0 L/min and 100.0 L/min) and particle sizes (0.1, 1.0, 3.0, 5.0, 10.0 pm) of salbutamol sulphate (density 20.0 kg/m3). The highest particle deposition occurred at flowrate 100.0 L/min and particle size of 1.0 pm as the deposition yield was 15.55% compared to flowrate 60 L/min and 30 L/min which were 10.50% and 3.09% respectively. Previous studies claimed that higher inhalation flowrate generated dispersion forces for sufficient inhalation flowrate thus enhanced higher deposition efficiency. The paired-samples T-test shows there were significant different (t= -15.400, df= 4, p <0.05) in the performance of particle depositions in MSLI simplified model with different flow rates (60.0 L/min and 100.0 L/min). Thus, the efficient fine particle deposition was significantly contributed by higher flowrate. This study also revealed that particle size ranges from 1.0 to 3.0 pm was the most suitable for inhalation treatment. Smaller particle size less than 1.0 pm was not suitable as it tended to exhale before it deposit of while larger particle (more than 5.0 pm) was not suitable for inhaled drug. In conclusion, vigorous air flow pattern promotes higher particle deposition. For efficient fine particle depositions, it is important to consider not only the particle size distribution, but also the flowrate as vital aerosol transportation agent. Statistical analysis, two-way ANOVA indicated that there was a statistically significant interaction between the effect of flowrate and particle size on particle deposition efficiency, F (8, 30)=5.857, p=0.00.