Variability in Constituents of E-Cigarette Products Containing Nicotine Analogues.

This study characterizes and quantifies constituents in 2 e-cigarette products to assess product consistency and inform future risk assessments.

Toxicity of waterpipe tobacco smoking: the role of flavors, sweeteners, humectants, and charcoal.

Waterpipe tobacco (WPT) smoking is a public health concern, particularly among youth and young adults. The global spread of WPT use has surged because the introduction of pre-packaged flavored and sweetened WPT, which is widely marketed as a safer tobacco alternative. Besides flavorants and sugars, WPT additives include humectants, which enhance the moisture and sweetness of WPT, act as solvents for flavors, and impart smoothness to the smoke, thus increasing appeal to users. In the United States, unlike cigarette tobacco flavoring (with the exception of menthol), there is no FDA product standard or policy in place prohibiting sales of flavored WPT. Research has shown that the numerous fruit, candy, and alcohol flavors added to WPT entice individuals to experience those flavors, putting them at an increased risk of exposure to WPT smoke-related toxicants. Additionally, burning charcoal briquettes-used as a heating source for WPT-contributes to the harmful health effects of WPT smoking. This review presents existing evidence on the potential toxicity resulting from humectants, sugars, and flavorants in WPT, and from the charcoal used to heat WPT. The review discusses relevant studies of inhalation toxicity in animal models and of biomarkers of exposure in humans. Current evidence suggests that more data are needed on toxicant emissions in WPT smoke to inform effective tobacco regulation to mitigate the adverse impact of WPT use on human health.

A review of the toxicity of ingredients in e-cigarettes, including those ingredients having the FDA's "Generally Recognized as Safe (GRAS)" regulatory status for use in food.

INTRODUCTION: Some firms and marketers of electronic cigarettes (e-cigarettes; a type of electronic nicotine delivery system (ENDS)) and refill liquids (e-liquids) have made claims about the safety of ingredients used in their products based on the term "GRAS or Generally Recognized As Safe" (GRAS). However, GRAS is a provision within the definition of a food additive under section 201(s) (21 U.S.C. 321(s)) of the U.S. Federal Food Drug and Cosmetic Act (FD&C Act). Food additives and GRAS substances are by the FD&C Act definition intended for use in food, thus safety is based on oral consumption; the term GRAS cannot serve as an indicator of the toxicity of e-cigarette ingredients when aerosolized and inhaled (i.e., vaped). There is no legal or scientific support for labeling e-cigarette product ingredients as "GRAS". This review discusses our concerns with the GRAS provision being applied to e-cigarette products and provides examples of chemical compounds that have been used as food ingredients but have been shown to lead to adverse health effects when inhaled. The review provides scientific insight into the toxicological evaluation of e-liquid ingredients and their aerosols to help determine the potential respiratory risks associated with their use in e-cigarettes. IMPLICATIONS: The rise in prevalence of e-cigarette use and emerging evidence of adverse effects, particularly on lung health, warrant assessing all aspects of e-cigarette toxicity. One development is manufacturers' stated or implied claims of the safety of using e-cigarette products containing ingredients determined to be "Generally Recognized As Safe" (GRAS) for use in food. Such claims, typically placed on e-cigarette product labels and used in marketing, are unfounded, as pointed out by the United States Food and Drug Administration (FDA)1 and the Flavor and Extract Manufacturers Association (FEMA)2. Assessment of inhalation health risks of all ingredients used in e-liquids, including those claimed to be GRAS, is warranted.

Cardiovascular Health Effects and Synthetic Cooling Agents in E-cigarettes Labeled as 'clear' Marketed in Massachusetts After the Tobacco Product Flavoring Ban.

Introduction: Massachusetts (MA) enacted statewide regulation on all flavored tobacco products in June 2020. Thereafter, electronic cigarettes (e-cigarettes) labeled 'clear' emerged on the market. We aimed to combine cardiovascular health effects with chemical analysis of 'clear' e-cigarettes. Methods: We measured acute changes in blood pressure and heart rate following a 10-minute structured use of participants' own e-cigarette, comparing 'clear' e-cigarette users with other flavored e-cigarette users and non-users. Chemical characterization and quantification of relevant flavorings and cooling agents (WS-3, WS-23) of 19 'clear'-labeled disposable e-cigarette liquids was carried out by GC/MS. Results: After the ban, participants that used 'clear' labeled e-cigarettes increased from 0% to 21%. Increase in diastolic blood pressure and heart rate was significantly greater in 'clear' e-cigarettes users (n=22) compared to both non-'clear' flavored e-cigarette users (n=114) and non-users (n=72). We saw similar results in heart rate when comparing Juul e-cigarette and 'clear' users; Juul was used as a reference as synthetic coolants WS-3 or WS-23 were not detected in these.All (19/19) 'clear' e-liquids were found to contain synthetic cooling agents WS-23 and/or WS-3, menthol (18/19), as well as other flavorings (12/19). Discussion: The detected presence of menthol alongside other flavorings in tested 'clear' products is a direct violation of the MA flavored tobacco product regulation, warranting stricter monitoring for new products and constituents. 'clear' e-cigarette use led to greater hemodynamic effects compared to other flavored e-cigarettes and Juul, which raises questions about the effect of cooling agents on users.

High Variability in Nicotine Analog Contents, Misleading Labeling, and Artificial Sweetener in New E-Cigarette Products Marketed as "FDA-Exempt".

The recent introduction of electronic cigarette products containing a synthetic nicotine analog, 6-methyl nicotine (6MN), challenges FDA's tobacco regulatory authority. A similar strategy is pursued by vendors of recently introduced e-cigarette liquids containing nicotinamide (NA), marketed as 'Nixotine' or 'Nixamide'. Compared to nicotine, 6MN is pharmacologically more potent at nicotinic receptors, and more toxic, raising concerns about increased addictiveness and adverse effects. Here, combinations of gas chromatography, high performance liquid chromatography and mass spectrometry were used to determine nicotine analogs, flavor and sweetener contents of e-cigarette liquids of the brands "SpreeBar" and ECBlend "Nixotine" products. All SpreeBar products, labelled as containing 5% 6-methyl nicotine, contained only 0.61-0.64% 6-methylnicotine, while "Nixotine" samples contained 7-46% less of the declared nicotinamide contents. Although "Nixotine" product labels did not list 6MN as an ingredient, small amounts of 6-methyl nicotine were detected. All 'SpreeBar' samples contained the artificial sweetener neotame (0.20-0.86µg/mg). Results identified significant discrepancies between declared and measured constituents of e-cigarette products containing nicotine alternatives. The discrepancy is misleading for consumers and raises concerns about production errors. 'SpreeBar' products also contained neotame, a high-intensity sweetener with high heat stability, likely increasing appeal to young and first-time users. Novel e-cigarette products with misleading labels containing nicotine analogs instead of nicotine on the US market is concerning and should be urgently addressed by lawmakers and regulators.

Chemical and physiological interactions between e-liquid constituents: cause for concern?

Studies of Electronic Nicotine Delivery Systems (ENDS) toxicity have largely focused on individual components such as flavour additives, base e-liquid ingredients (propylene glycol, glycerol), device characteristics (eg, model, components, wattage), use behaviour, etc. However, vaping involves inhalation of chemical mixtures and interactions between compounds can occur that can lead to different toxicities than toxicity of the individual components. Methods based on the additive toxicity of individual chemical components to estimate the health risks of complex mixtures can result in the overestimation or underestimation of exposure risks, since interactions between components are under-investigated. In the case of ENDS, the potential of elevated toxicity resulting from chemical reactions and interactions is enhanced due to high operating temperatures and the metallic surface of the heating element. With the recent availability of a wide range of e-liquid constituents and popularity of do-it-yourself creation of e-liquid mixtures, the need to understand chemical and physiological impacts of chemical combinations in ENDS e-liquids and aerosols is immediate. There is a significant current knowledge gap concerning how specific combinations of ENDS chemical ingredients result in synergistic or antagonistic interactions. This commentary aims to review the current understanding of chemical reactions between e-liquid components, interactions between additives, chemical reactions that occur during vaping and aerosol properties and biomolecular interactions, all of which may impact physiological health.

Comparison of emissions across tobacco products: A slippery slope in tobacco control.

In this narrative review, we highlight the challenges of comparing emissions from different tobacco products under controlled laboratory settings (using smoking/vaping machines). We focus on tobacco products that generate inhalable smoke or aerosol, such as cigarettes, cigars, hookah, electronic cigarettes, and heated tobacco products. We discuss challenges associated with sample generation including variability of smoking/vaping machines, lack of standardized adaptors that connect smoking/vaping machines to different tobacco products, puffing protocols that are not representative of actual use, and sample generation session length (minutes or number of puffs) that depends on product characteristics. We also discuss the challenges of physically characterizing and trapping emissions from products with different aerosol characteristics. Challenges to analytical method development are also covered, highlighting matrix effects, order of magnitude differences in analyte levels, and the necessity of tailored quality control/quality assurance measures. The review highlights two approaches in selecting emissions to monitor across products, one focusing on toxicants that were detected and quantified with optimized methods for combustible cigarettes, and the other looking for product-specific toxicants using non-targeted analysis. The challenges of data reporting and statistical analysis that allow meaningful comparison across products are also discussed. We end the review by highlighting that even if the technical challenges are overcome, emission comparison may obscure the absolute exposure from novel products if we only focus on relative exposure compared to combustible products.

Synthetic Cooling Agent and Other Flavor Additives in "Non-Menthol" Cigarettes Marketed in California and Massachusetts After Menthol Cigarette Bans.

This study uses a bioassay and chemical analysis to determine the proportion of newly introduced "non-menthol" cigarette brands with sensory cooling effects, cooling agents added, and any other flavor additives after menthol cigarette bans.

Synthetic cooling agent in oral nicotine pouch products marketed as 'Flavour-Ban Approved'.

BACKGROUND: US sales of oral nicotine pouches (ONPs) have rapidly increased, with cool/mint-flavoured ONPs the most popular flavour category. Restrictions on sales of flavoured tobacco products have either been implemented or proposed by several US states and localities. Zyn, the most popular ONP brand, is marketing Zyn Chill and Zyn Smooth as 'Flavour-Ban Approved' or 'unflavoured', probably to evade flavour bans and increase product appeal. At present, it is unclear whether these ONPs are indeed free of flavour additives that can impart pleasant sensations such as cooling. METHODS: Sensory cooling and irritant activities of 'Flavour-Ban Approved' Zyn ONPs, Chill and Smooth, along with minty varieties (Cool Mint, Peppermint, Spearmint, Menthol), were analysed by Ca2+ microfluorimetry in HEK293 cells expressing the cold/menthol (TRPM8) or menthol/irritant receptor (TRPA1). Flavour chemical content of these ONPs was analysed by gas chromatography/mass spectrometry. RESULTS: Zyn Chill ONP extracts robustly activated TRPM8, with much higher efficacy (39%-53%) than the mint-flavoured ONPs. In contrast, mint-flavoured ONP extracts elicited stronger TRPA1 irritant receptor responses than Chill extracts. Chemical analysis demonstrated that Chill exclusively contained WS-3, an odourless synthetic cooling agent, while mint-flavoured ONPs contained WS-3 together with mint flavourants. CONCLUSIONS: ONP products marketed as 'Flavour-Ban Approved' or 'unflavoured' contain flavouring agents, proving that the manufacturer's advertising is misleading. Synthetic coolants such as WS-3 can provide a robust cooling sensation with reduced sensory irritancy, thereby increasing product appeal and use. Regulators need to develop effective strategies for the control of odourless sensory additives used by the industry to bypass flavour bans.

Synthetic Cooling Agent and Candy Flavors in California-marketed "non-Menthol" Cigarettes.

RATIONALE: The ban of menthol cigarettes is one of the key strategies to promote smoking cessation in the United States. Menthol cigarettes are preferred by young beginning smokers for smoking initiation. Almost 90% of African American smokers use menthol cigarettes, a result of decades-long targeted industry marketing. Several states and municipalities already banned menthol cigarettes, most recently California, effective on December 21, 2022. In the weeks before California's ban took effect, the tobacco industry introduced several "non-menthol" cigarette products in California, replacing previously mentholated brands. Here, we hypothesize that tobacco companies replaced menthol with synthetic cooling agents to create a cooling effect without using menthol. Similar to menthol, these agents activate the TRPM8 cold-menthol receptor in sensory neurons innervating the upper and lower airways. METHODS: Calcium microfluorimetry in HEK293t cells expressing the TRPM8 cold/menthol receptors was used to determine sensory cooling activity of extracts prepared from these "non-menthol" cigarette brands, and compared to standard menthol cigarette extracts of the same brands. Specificity of receptor activity was validated using TRPM8-selective inhibitor, AMTB. Gas chromatography mass spectrometry (GCMS) was used to determine presence and amounts of any flavoring chemicals, including synthetic cooling agents, in the tobacco rods, wrapping paper, filters and crushable capsule (if present) of these "non-menthol" cigarettes. RESULTS: Compared to equivalent menthol cigarette extracts, several California-marketed "non-menthol" cigarette extracts activated cold/menthol receptor TRPM8 at higher dilutions and with stronger efficacies, indicating substantial pharmacological activity to elicit robust cooling sensations. Synthetic cooling agent, WS-3, was detected in tobacco rods of several of these "non-menthol" cigarette brands. Crushable capsules added to certain "non-menthol" crush varieties contained neither WS-3 nor menthol but included several "sweet" flavorant chemicals, including vanillin, ethyl vanillin and anethole. CONCLUSION: Tobacco companies have replaced menthol with the synthetic cooling agent, WS-3, in California-marketed "non-menthol" cigarettes. WS-3 creates a cooling sensation similar to menthol, but lacks menthol's characteristic "minty" odor. The measured WS-3 content is sufficient to elicit cooling sensations in smokers, similar to menthol, that facilitate smoking initiation and act as a reinforcing cue. Regulators need to act quickly to prevent the tobacco industry from bypassing menthol bans by substituting menthol with synthetic cooling agents, and thereby thwarting smoking cessation efforts.