Characterization of a rapid condensate collection apparatus for in vitro assays of electronic nicotine delivery systems.

In vitro testing of Electronic Nicotine Delivery System (ENDS) aerosol condensates is important in evaluating their potential toxicity. Collecting sufficient condensate for these tests is a time consuming and costly procedure. The "triple puff (TP)" is a novel system which collects the aerosol from three ENDS devices sequentially into a single filter pad and impinger. The TP substantially reduces condensate collection time relative to the conventional single ENDS, single puff (SP), device system. Both the TP and SP (using two puffing profiles) were used to generate condensates from JUUL ENDS e-liquid Mint 5.0% (nicotine by weight). Aerosols were collected using the filter pad and ethanol-containing impinger method. Condensates produced with the SP and TP were compared for concentrations of primary constituents and carbonyl compounds as well as for their cytotoxicity (OECD 129), mutagenicity (OECD 471) and genotoxicity (OECD 487). Condensates generated with the SP and TP, regardless of puffing regimen, were very similar chemically and equivalent in the biological assays tested (not cytotoxic, mutagenic, or genotoxic). The TP device significantly reduces production time of ENDS condensates relative to the standard SP method and thus may facilitate further research by reducing the time and effort required to collect ENDS condensates.

Comparison of experimentally measured and computational fluid dynamic predicted deposition and deposition uniformity of monodisperse solid particles in the Vitrocell® AMES 48 air-liquid-interface in-vitro exposure system.

Accurately determining the delivered dose is critical to understanding biological response due to cell exposure to chemical constituents in aerosols. Deposition efficiency and uniformity of deposition was measured experimentally using monodisperse solid fluorescent particles with mass median aerodynamic diameters (MMAD) of 0.51, 1.1, 2.2 and 3.3 µm in the Vitrocell® AMES 48 air-liquid-interface (ALI) in vitro exposure system. Experimental results were compared with computational fluid dynamic, (CFD; using both Lagrangian and Eulerian approaches) predicted deposition efficiency and uniformity for a single row (N = 6) of petri dishes in the Vitrocell® AMES 48 system. The average experimentally measured deposition efficiency ranged from 0.007% to 0.43% for 0.51-3.3 µm MMAD particles, respectively. There was good agreement between average experimentally measured and the CFD predicted particle deposition efficiency, regardless of approach. Experimentally measured and CFD predicted average uniformity of deposition was greater than 45% of the mean for all particle diameters. During this work a new design was introduced by the manufacturer and evaluated using Lagragian CFD. Lagragian CFD predictions showed better uniformity of deposition, but reduced deposition efficiency with the new design. Deposition efficiency and variability in particle deposition across petri dishes for solid particles should be considered when designing exposure regimens using the Vitrocell® AMES 48 ALI in vitro exposure system.