Experimental and CFD study of the deposition of inhalable particles in the induction port of a cascade impactor

DE CHARRAS, YAMILA; RAMÍREZ RIGO, M. VERÓNICA; BERTIN, DIEGO E.

Buenos Aires

Congreso; WCCE11 - 11th Congress Of Chemical Engineering; 2023

AAIQ Asociación Argentina de Ingenieros Químicos

The testing of pharmaceutical aerosols includes measuring the aerodynamic particle size distribution, which is usually performed on cascade impactors. In particular, in the Next Generation Impactor (NGI), the aerosol dose is introduced to the NGI through an induction port (IP), being separated into different aerodynamic diameter ranges by seven stages and a micro-orifice collector. The IP play an important role to estimate the oropharyngeal deposition fraction. While IP retains mainly large particles, it also tends to retain particles in the respirable range. In this work, the deposition of particles in the IP of an NGI is studied, both experimentally and through CFD simulations. Experimental assays are performed for a pressurized metered-dose inhalers (pMDI) alone and with 2 commercial valved holding chambers (VHCs). For each case, the total mass deposition that occurs in the IP is measured, as well as the MMAD of the aerosol leaving the IP.The CFD model, used to study the deposition of particles of different sizes in the IP, was validated with the experimental values obtained. The results indicate that the IP effectively retains a fraction of particles corresponding to the breathable range, although the greatest retention occurs for larger particles. A particle separation efficiency curve is obtained from the CFD results of the IP, which is used to predict the MMAD of the aerosol emitted by the pMDI.