Brian M. Keyser,1 Robert Leverette,1 Michael Hollings,2 Adam Seymour,2 Randy J. Weidman,3 Carlton J. Bequette,3 and Kristen Jordan1
1 Scientific & Regulatory Affairs, RAI Services Company, Winston-Salem, North Carolina, USA.
2 Labcorp Early Development Laboratories Ltd., Harrogate, North Yorkshire, United Kingdom.
3 RJ Reynolds Tobacco Company, Winston-Salem, North Carolina, USA
This study utilized a Vitrocell Ames 48 exposure module climatic chamber. Cigarette smoke and eHTP/ENDS aerosol was generated using a Vitrocell VC10. Different concentrations of whole smoke or aerosol were achieved by altering the diluting airflow using mass flow controllers The dosimetry measure used for assessing both combustible and NGTP aerosols in this characterization exercise was the laser photometer purchased from Vitrocell Systems and harmonized for each tobacco product type used in this study. To evaluate the multiple dosimetry techniques, pairwise comparisons were made between the two Vitrocell Ames 48 exposure modules for each of the three test articles.
Introduction: The Vitrocell Ames 48 whole-aerosol exposure module offers a high-throughput platform for airagar-interface exposures that mimic human exposure conditions for assessing potential mutagenic activity of a test article. The aim of this study was to characterize the Vitrocell Ames 48 exposure module for assessment of aerosolized tobacco products utilizing multiple dosimetry techniques and nicotine deposition as determined by chemical analysis.
Materials and Methods: Characterization was performed using the Vitrocell VC10 smoking machine and three nicotine containing tobacco product test articles: Kentucky Reference cigarettes (3R4F), a commercially available electrically heated tobacco product (eHTP), and an Electronic Nicotine Delivery System (ENDS). The following dosimetry tools were used: Aerosol photometers (using area under curve values, +AUC), free glycerol deposition in phosphate-buffered saline (PBS), fluorescence of anhydrous dimethyl sulfoxide (DMSO)-captured smoke particulate matter, and analytical determination of nicotine in PBS and DMSO. Characterization of 3R4F Kentucky Reference cigarettes was examined over a diluting airflow range 8 to 0.5 L/min; eHTP and ENDS were examined over a diluting airflow range of 4 to 0 L/min (undiluted).
Results: Results from the dosimetry techniques showed that whole smoke from 3R4F cigarettes and whole aerosol from eHTP and ENDS demonstrated reproducible and consistent delivery, with results being consistent between experiments and within each airflow.
Conclusion: These results show that this exposure module is fit for purpose using these three tobacco product types.