The in vitro mutagenic potential of the aerosol from Vype^® ePen e-cigarette was assessed using the Ames assay. E-cigarette aerosol was trapped on a Cambridge filter pad, eluted in DMSO and compared to cigarette smoke total particulate matter (TPM), generated in the same manner. E-cigarette and cigarette smoke aerosols were generated on a Vitrocell^® VC 10 smoking robot and compared using a modified scaled-down 35 mm air agar interface (AAI) methodology.

E-cigarette aerosol collected matter (ACM) was found to be negative in the 85 mm Ames assay in strains TA98 and TA100 when conducted to OECD TG471, at concentrations up to 2400 µg/plate. E-cigarette aerosol was also found to be negative in both strains after an AAI aerosol exposure, when tested between 1-12 L/min dilution for up to 3-hours (360 puffs). In contrast, cigarette smoke TPM and aerosol from 3R4F reference cigarettes were found to be mutagenic in both tester strains, under comparable test conditions to that of e-cigarettes. To confirm these negative findings with e-cigarette exposure, further studies investigated extreme exposures up to 900 puffs. Some evidence of thinning of the background lawn and a marked reduction in revertants in TA98 and TA100 was observed following 900 puffs of undiluted e-cigarette aerosols. The data demonstrates that e-cigarette aerosols remained non-mutagenic under extreme testing conditions.

This novel whole aerosol approach could be used in a targeted manner to support e-cigarette assessments, and may even be useful in understanding the nature of the product in its extremes. The next key step is to contextualise against human consumption data, to ensure that these products are being tested within the constraints of their manufacturers’ specifications and intended use. Furthermore, in vitro dosimetry approaches should be considered to draw more accurate comparisons between cigarette smoke, e-cigarette aerosol exposures and human use.