Computational Studies of Aerosolized Drug Deposition in Human Respiratory Tract Vivek Kumar Srivastav, Anuj Jain, and Akshoy Ranjan Paul Abstract The administration of drug and vaccine using pMDI through mouth in a human respiratory tract (HRT) is important for treatment of local and systemic diseases. Computational fluid dynamics (CFD) is used to gain an insight on the effect of various parameters on aerosol drug deposition in a CT-scan-based three- dimensional model of human respiratory tract (HRT). In the present study, the aerosol drug deposition is estimated using discrete phase model (DPM) and LRN k-ω turbulence model in CFD. The effect of variation of inhalation rates, particle size, aerosol injection velocity, nozzle spray angle on aerosol deposition efficiency in oral cavity and up to sixth-generation bronchi model was studied. The results reveal that optimum nozzle spray angle is around 45–50°, the particle size should be below 5 μm, and inhalation rate above 40 L/min. The outcome of the present study will be helpful for efficient design of pMDI inhaler and for the effective treatment of respiratory and other diseases. Keywords Human respiratory tract (HRT) · CT-scan model · Pressurized metered-dose inhaler (pMDI) · Aerosol transport · Drug deposition 1 Introduction A pressurized metered-dose inhaler (pMDI) is a medical device that on operating delivers a specific amount of medication in the form of a short burst of aerosolized medicine [1]. The medication is usually self-administered by the patient into the body through the oral cavity into the human respiratory tract via inhalation. It is the most widely used drug delivery system for treating asthma, chronic obstructive pulmonary disease (COPD), and other respiratory and systemic diseases. V. K. Srivastav Motihari College of Engineering, Motihari, Bihar, India A. Jain · A. R. Paul (B ) Motilal Nehru National Institute of Technology Allahabad, Prayagraj, Uttar Pradesh, India e-mail: arpaul@mnnit.ac.in © Springer Nature Singapore Pte Ltd. 2021 L. Venkatakrishnan et al. (eds.), Proceedings of 16th Asian Congress of Fluid Mechanics, Lecture Notes in Mechanical Engineering, https://doi.org/10.1007/978-981-15-5183-3_2 11