Synthetic Cooling agents in US-marketed E-cigarette Refill Liquids and Popular Disposable E-cigarettes: Chemical analysis and Risk assessment.

Introduction:
This text presents a study on the presence and potential health risks of synthetic cooling agents in US-marketed e-cigarettes. The study analyzed the levels of synthetic cooling agents (WS-3 and WS-23) as well as important pepper-mint (menthol and menthone) and spearmint (carvone) flavor chemicals in US-marketed e-cigarettes and disposable e-cigarettes of the brand Puffbar. Power specifications and chemical analysis of these products were performed, and the health risks associated with synthetic coolant exposure from e-cigarette use were assessed using the Margin of Exposure (MOE) risk assessment parameter.

Key Points:

* Synthetic cooling agents (WS-3/WS-23) were present in US-marketed e-cigarettes, at levels that may result in consumer exposures exceeding safety thresholds set by regulatory agencies.
* Synthetic coolants are not only found in mint- or menthol-flavored products but also in fruit- and candy-flavored products, including popular disposable e-cigarette products such as Puffbar.
* The study found that Puffbar power specifications are identical to Juul devices.
* The analysis revealed that 24 out of 25 refill e-liquids contained WS-3, and 13 out of 14 Puffbar flavors contained either WS-23 or WS-3.
* The modeling of consumption of WS-3 from vaped e-liquids resulted in MOEs below the safe margin of 100 for most daily use scenarios.
* MOEs for WS-23 were <100 for 10/13 Puffbar flavors in all use scenarios.
* Exposure of airway-epithelial cells in vitro to various concentrations of synthetic coolants and WS-23 containing e-liquids demonstrated a dose-dependent cellular toxicity.
* The study suggests that synthetic cooling agents are widely used in e-cigarettes, potentially as a replacement for menthol or to add cooling "notes" to nonmenthol flavors, and may bypass current and future regulatory limits on menthol content in tobacco products.

Main Message:
The study highlights the widespread use of synthetic cooling agents in e-cigarettes and the potential health risks associated with their exposure. These agents are not only found in mint- or menthol-flavored products but also in fruit- and candy-flavored products, including popular disposable e-cigarette products. The levels of these agents in e-cigarettes may exceed safety thresholds set by regulatory agencies, and they may be used as a replacement for menthol or to add cooling notes to nonmenthol flavors, potentially bypassing current and future regulatory limits on menthol content in tobacco products. Therefore, regulators need to consider the additional health risks associated with exposure to synthetic cooling agents in e-cigarettes.

Jabba SV, Erythropel hC, Torres DG, et al. Synthetic Cooling agents in US-marketed E-cigarette Refill Liquids and Popular Disposable E-cigarettes: Chemical analysis and Risk assessment. Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco. 2022;24(7):1037-1046. doi:10.1093/ntr/ntac046