Multicomponent aerosol particle deposition in a realistic cast of the human upper respiratory tract

Abstract

Inhalation of aerosols generated by electronic cigarettes leads to deposition of multiple chemical compounds in the human airways. In this work, an experimental method to determine regional deposition of multicomponent aerosols in an in vitro segmented, realistic human lung geometry was developed and applied to two aerosols, i.e. a monodisperse glycerol aerosol and a multicomponent aerosol. The method comprised the following steps: (1) lung cast model preparation, (2) aerosol generation and exposure, (3) extraction of deposited mass, (4) chemical quantification and (5) data processing. The method showed good agreement with literature data for the deposition efficiency when using a monodisperse glycerol aerosol, with a mass median aerodynamic diameter (MMAD) of 2.3 lm and a constant flow rate of 15 L/min. The highest deposition surface density rate was observed in the bifurcation segments, indicating inertial impaction deposition. The experimental method was also applied to the deposition of a nebulized multicomponent aerosol with a MMAD of 0.50 lm and a constant flow rate of 15 L/min. The deposited amounts of glycerol, propylene glycol and nicotine were quantified. The three analyzed compounds showed similar deposition patterns and fractions as for the monodisperse glycerol aerosol, indicating that the compounds most likely deposited as parts of the same droplets. The developed method can be used to determine regional deposition for multicomponent aerosols, provided that the compounds are of low volatility. The generated data can be used to validate aerosol deposition simulations and to gain insight in deposition of electronic cigarette aerosols in human airways. ARTICLE HISTORY

A framework for in vitro systems toxicology assessment of e-liquids

“…Dosimetry assessment will provide the necessary context for estimating the human exposure doses. Initial efforts have augmented our understanding of aerosol deposition in the human lung, such as an evaluation of particle deposition as a function of the airway generation (Manigrasso et al., 2015 ), and a determination and quantification of the deposition of aerosol particles (of a monodisperse glycerol and multicomponent e-cig aerosols) in the human upper airway using an in vitro lung cast model (Nordlund et al., 2015 ). Nevertheless, in vitro–in vivo dosimetry remains a challenging task.…”

A Case Study for the Comparison ofIn VitroData Across Multiple Aerosol Exposure Studies with Extrapolation to Human Dose

“…To move into more quantitative measurements, Carbon monoxide and nicotine have been widely used as exposure markers. 14,[32][33][34] Recent advances have now seen vapor phase chemicals measured within the exposure module to characterize dose and aerosol delivery. 18 However, these techniques require method development and optimization to increase method sensitivity and selectivity and are currently not widely available.…”

A Review of Respiratory Anatomical Development, Air Flow Characterization and Particle Deposition

“…A wide range of in vivo, in vitro and computational fluid dynamics (CFD) studies have been performed for flow-field analysis and microparticle TD in the extrathoracic airways [15,[100][101][102][103][104][105]. The critical understanding of the local and regional micro-size aerosol deposition is important for assessing pulmonary health risk and drug deposition efficacy.…”

“…A wide range of studies has been conducted for flow field characterization and particle TD in the tracheobronchial airways [101,[116][117][118][119][120][121][122][123][124][125][126]. Almost all of these studies consider non-realistic symmetric [127][128][129][130] and non-realistic asymmetric [88,93,131] anatomical models for airflow analysis and particle TD.…”