Characterization of smoke and aerosol deliveries from combustible cigarettes, heated tobacco products and electronic nicotine delivery systems in the Vitrocell® Mammalian 6/48 exposure module.

Introduction:
This text describes a study that characterizes the Vitrocell ® Mammalian 6/48 exposure module, a system used to expose in vitro test systems to cigarette smoke, e-cigarette aerosol, and heated tobacco product aerosol. The study uses multiple dosimetry techniques to ensure the system's suitability and replicability for exposure to these aerosols.

Key points:

* The study used two Vitrocell ® Mammalian 6/48 exposure modules and characterized them using a range of dosimetry techniques.
* Cigarette smoke, e-cigarette aerosol, and heated tobacco product aerosol were generated using a Vitrocell ® VC10 ® smoking machine.
* Photometers were used to measure the aerosol particle concentration, and nicotine concentrations were determined analytically by LC/MS.
* humectant amount and distribution were assessed for e-cigarettes and heated tobacco products by the quantification of free glycerol in a phosphate buffered saline (PBS) trap.
* Total particulate matter (TPM) was assessed in the 3R4F cigarettes by the fluorescence of the particulate at 485 nm in anhydrous dimethyl sulfoxide (DMSO) trap within the exposure.
* Dose was adjusted by means of the addition of ambient air to dilute the whole smoke/aerosol in L/min and sampled into the system at a rate of 5 mL/min.
* Dosimetric analysis of the system showed good concordance within replicates and demonstrated that the Vitrocell ® Mammalian 6/48 is a viable means for genotoxic assessment of aerosol generated from both conventional cigarettes and NGTP.
* The study highlights the need to tailor dosimetry approaches to different aerosols due to variations in the physio-chemical composition and recommends a multi-dosimetry approach.

Main message:
The Vitrocell ® Mammalian 6/48 exposure module is a suitable system for genotoxic assessment of aerosol generated from both conventional cigarettes and NGTP. however, the study demonstrates the need to tailor dosimetry approaches to different aerosols due to variations in the physio-chemical composition. The authors recommend a multi-dosimetry approach to ensure accurate and reliable assessment of these aerosols.

Keyser BM, Leverette R, hollings M, et al. Characterization of smoke and aerosol deliveries from combustible cigarettes, heated tobacco products and electronic nicotine delivery systems in the Vitrocell® Mammalian 6/48 exposure module. Toxicology reports. 2022;9:1985-1992. doi:10.1016/j.toxrep.2022.11.001