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Comparative Study
. 2020 Jul 20;33(7):1882-1887.
doi: 10.1021/acs.chemrestox.0c00088. Epub 2020 Jun 2.

Free Radical Production and Characterization of Heat-Not-Burn Cigarettes in Comparison to Conventional and Electronic Cigarettes

Zachary T Bitzer  1 , Reema Goel  1 , Neil Trushin  1 , Joshua Muscat  1 , John P Richie Jr  1
Affiliations
Comparative Study

Free Radical Production and Characterization of Heat-Not-Burn Cigarettes in Comparison to Conventional and Electronic Cigarettes

Zachary T Bitzer et al. Chem Res Toxicol. .

Abstract

With conventional cigarettes, the burning cone reaches temperatures of >900 °C, resulting in the production of numerous toxicants and significant levels of highly reactive free radicals. In attempts to eliminate combustion while still delivering nicotine and flavorings, a newer alternative tobacco product has emerged known as "heat-not-burn" (HnB). These products heat tobacco to temperatures of 250-350 °C depending on the device allowing for the volatilization of nicotine and flavorants while potentially limiting the production of combustion-related toxicants. To better understand how the designs of these new products compare to conventional cigarettes and different styles of electronic cigarettes (e-cigs), we measured and partially characterized their production of free radicals. Smoke or aerosols were trapped by a spin trap phenyl-N-tert-butylnitrone (PBN) and analyzed for free radicals using electron paramagnetic resonance (EPR). Free radical polarity was assessed by passing the aerosol or smoke through either a polar or nonpolar trap prior to being spin trapped with PBN. Particulate-phase radicals were detected only for conventional cigarettes. Gas-phase free radicals were detected in smoke/aerosol from all products with levels for HnB (IQOS, Glo) (12 pmol/puff) being similar to e-cigs (Juul, SREC, box mod e-cig) and hybrid devices (Ploom) (5-40 pmol/puff) but 50-fold lower than conventional cigarettes (1R6F). Gas phase radicals differed in polarity with HnB products and conventional cigarettes producing more polar radicals compared to those produced from e-cigs. Free radical production should be considered in evaluating the toxicological profile of nicotine delivery products and identification of the radicals is of paramount importance.

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Figures

Figure 1.
Figure 1.
Heat-not-burn products and their associated heatsticks/caps.
Figure 2.
Figure 2.
Gas-phase and particulate-phase radicals per puff. Different letters represent statistical differences (p < 0.05) between gas-phase radicals. Asterisk (*) represent statistically significant difference (p < 0.05) between particulate-phase radicals.
Figure 3.
Figure 3.
Gas-phase and particulate-phase radicals on a per mg nicotine basis. Different letters represent statistical differences (p < 0.05) between gas-phase radicals. Asterisk (*) represent statistically significant difference (p < 0.05) between particulate-phase radicals.
See this image and copyright information in PMC

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