Biology subjects

Erythropel, H. C.

Publications and source records attributed to Erythropel, H. C..

5 recordsLinked to original sources

bioRxiv2026

Effects of commercial unflavored and vanilla-flavored e-liquids on nicotine intake and withdrawal

Electronic cigarette liquids (e-liquids) often contain flavors and solvents that may influence nicotine addiction. In this study, we characterized the dose-response relationship of commercial unflavored nicotine e-liquids and investigated the impact of vanilla-flavored e-liquids on nicotine vapor self-administration (VSA) and withdrawal in rats. Male adolescent Sprague Dawley rats self-administered aerosols generated from commercial e-liquids containing 0, 3, 6, or 12 mg/ml nicotine in a propylene glycol (PG) and glycerol (G) vehicle. The vehicle (0 mg/ml nicotine) supported robust VSA, indicating the reinforcing effects of PG/G vapor. 3 mg/ml nicotine did not support VSA, while both 6 and 12 mg/ml nicotine concentrations produced significant reinforcement, with 6 mg/ml yielding the most stable responding. The 6 mg/ml concentration was selected for subsequent comparisons with vanilla-flavored e-liquids. Vanilla flavor (0 mg/ml nicotine) led to maintained VSA behavior, confirming its reinforcing effects. However, the combination of vanilla and nicotine (6 mg/ml) did not alter nicotine intake or withdrawal severity, as assessed by mecamylamine-precipitated somatic signs. Blood nicotine and cotinine levels were similar between nicotine and vanilla + nicotine conditions, indicating that vanilla flavor did not affect systemic nicotine metabolism. Additionally, the PG/G vehicle induced significant somatic signs, suggesting that vapor exposure itself, independent of nicotine, contributes to these physiological responses. These findings provide critical insights into the reinforcing and physiological effects of both nicotine and non-nicotine constituents in e-cigarette aerosols, underscoring the need for future studies and regulatory strategies that consider the abuse liability of flavors and solvents, such as PG/G, particularly among adolescents. Significance StatementFlavored electronic nicotine delivery systems raise concern for promoting nicotine use in youth. Using a rat vapor self-administration model, we show nicotine produces concentration-dependent reinforcement, while vanilla flavor is reinforcing but does not enhance nicotine intake or withdrawal.

pharmacology and toxicology↗

bioRxiv2025

Absence of Sensory Cooling Activity and Cooling Agents from California's New ''Non-Menthol'' Cigarettes Marketed in 2025

BackgroundSince late 2022, the sale of most flavoured tobacco products has been prohibited in California, including menthol cigarettes. Tobacco companies responded by introducing "non-menthol" cigarettes in which menthol was replaced with WS-3, an odorless synthetic cooling agent to elicit cooling sensations similar to menthol. Legislation enacted in 2024 banned the addition of cooling characterizing flavours in tobacco products in California. However, the industry continues to market "non-menthol" cigarettes in the state, with very similar package designs. It is unknown whether these cigarettes contain a cooling agent. MethodsAvailable Newport-branded "non-menthol" cigarettes were purchased in California in 2025, extracted and tested for sensory cooling activity by Ca2+ microfluorimetry of HEK293T cells expressing the human TRPM8 cold/menthol receptor. Chemical analysis was performed by gas chromatography - mass spectrometry (GCMS). "Non-menthol" and menthol cigarettes marketed in 2023-24 served as controls. ResultsExtracts from Newport-branded "non-menthol" cigarettes marketed in California in 2025 did not elicit sensory cooling activity. Chemical analysis confirmed the absence of menthol and any of the major commercial synthetic cooling agents. ConclusionsThe tobacco industry removed sensory cooling agents from "non-menthol" cigarettes marketed in California. However, this did not result in the market withdrawal of "non-menthol" cigarettes in the state. "Non-menthol" cigarettes in California continue to be marketed with package designs resembling those of former menthol cigarettes, signaling the potential presence of a characterising flavour.

pharmacology and toxicology↗

bioRxiv2023

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

RATIONALEThe 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 Californias 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. METHODSCalcium 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. RESULTSCompared 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. CONCLUSIONTobacco 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 menthols 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.

pharmacology and toxicology↗

bioRxiv2023

Synthetic Cooling Agent in Oral Nicotine Pouch Products Marketed as "Flavor Ban Approved"

BackgroundUS sales of oral nicotine pouches (ONPs) have rapidly increased, with cool/mint-flavored ONPs the most popular. Restrictions on sales of flavored 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 "Flavor-Ban Approved", probably to evade flavor bans. At present it is unclear whether these ONPs are indeed free of flavor additives that can impart pleasant sensations such as cooling. MethodsSensory cooling and irritant activities of "Flavor-Ban Approved" ONPs, Zyn-"Chill" and "Smooth", along with "minty" varieties (Cool Mint, Peppermint, Spearmint, Menthol), were analyzed by Ca2+ microfluorimetry in HEK293 cells expressing the cold/menthol (TRPM8) or menthol/irritant receptor (TRPA1). Flavor chemical content of these ONPs was analyzed by GC/MS. ResultsZyn-"Chill" ONP extracts robustly activated TRPM8, with much higher efficacy (39-53%) than the mint-flavored ONPs. In contrast, mint-flavored ONP extracts elicited stronger TRPA1 irritant receptor responses than Zyn-"Chill" extracts. Chemical analysis demonstrated the presence of WS-3, an odorless synthetic cooling agent, in Zyn-"Chill" and several other mint-flavored Zyn-ONPs ConclusionsSynthetic cooling agents such as WS-3 found in Flavor-Ban Approved Zyn-"Chill" can provide a robust cooling sensation with reduced sensory irritancy, thereby increasing product appeal and use. The label "Flavor-Ban Approved" is misleading and may implicate health benefits. Regulators need to develop effective strategies for the control of odorless sensory additives used by the industry to bypass flavor bans.

pharmacology and toxicology↗

bioRxiv2021

Synthetic Cooling Agents in US-marketed E-cigarette Refill Liquids and Disposable E-cigarettes: Chemical Analysis and Risk Assessment.

BackgroundMenthol, through its cooling and pleasant sensory effects, facilitates smoking and tobacco product initiation, resulting in the high popularity of mint/menthol-flavored E-cigarettes. More recently, E-cigarette vendors started marketing synthetic cooling agents as additives that impart a cooling effect but lack a characteristic minty odor. Knowledge about content of synthetic coolants in US-marketed E-cigarette products and associated health risks is limited. MethodsE-liquid vendor sites were searched with the terms "koolada", "kool/cool", "ice", or WS-3/WS-23, denoting individual cooling agents, and relevant refill E-liquids were purchased. "Ice" flavor varieties of Puffbar, the most popular disposable E-cigarette brand, were compared with non-"Ice" varieties. E-liquids were characterized, and synthetic coolants quantified using GC/MS. Margin of exposure (MOE), a risk assessment parameter, was calculated to assess the risk associated with synthetic coolant exposure from E-cigarette use. ResultsWS-3 was detected in 24/25 refill E-liquids analyzed. All Puffbar flavor varieties contained either WS-23 (13/14) or WS-3 (5/14), in both "Ice"- and non-"Ice" flavors. Modeling 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. Puffbar power specifications are identical to Juul devices. ConclusionsSynthetic 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. ImplicationsSynthetic cooling agents are widely used in "kool/cool"- and "ice"-flavored E-liquids and in E-liquids without these labels, both as a potential replacement for menthol or to add cooling notes to non-menthol flavors. These agents may be used to bypass current and future regulatory limits on menthol content in tobacco products, and not just E-cigarettes. Since synthetic cooling agents are odorless, they may not fall under the category of "characterizing flavor", potentially circumventing regulatory measures based on this concept. Regulators need to consider the additional health risks associated with exposure to synthetic cooling agents.

pharmacology and toxicology↗