Analysis and differentiation of tobacco-derived and synthetic nicotine products: Addressing an urgent regulatory issue

E-cigarette market share by nicotine claims

Background

Nicotine forms (salt vs. freebase) and isomers (synthetic vs. tobacco-derived) are key characteristics of e-cigarettes that manufacturers manipulate, and "tobacco-free" claims may have served to attract new consumers and increase their intention to use.

Method

This study presents a snapshot of nicotine marketing claims for e-cigarettes using Nielsen ScanTrack data from brick-and-mortar stores. Market share was calculated as the ratio of unit sales of each nicotine claim category to the total unit sales of e-cigarettes during the four weeks ending 1-20-2024.

Results

We summarized the market share for the following six nicotine form/isomer category: 1) nicotine (77%), 2) nicotine salt (10%), 3) synthetic nicotine (2%), 4) zero tobacco or tobacco-free (2%), 5) zero nicotine or nicotine-free (0.03%), and 6) no claim or CBD/hemp/cannabis (9%).

Conclusion

The market share of products that explicitly carried nicotine salt claims (10%) or synthetic nicotine or tobacco-free claims (2% each) was notable. This study informs regulatory authorities on the recent trend of nicotine claims marketed by the e-cigarette industry, which may be contributing to the use of these products or addiction to nicotine among young people and non-users.

Qualitative and Quantitative Analyses of the Enantiomers of Nicotine and Nornicotine Employing Chiral Supercritical Fluid Chromatography

An optimized method employing chiral supercritical fluid chromatography with diode array UV-VIS detection has been developed for the quantitative analysis of nicotine and nornicotine enantiomer distributions. The method parameters that were optimized included: column type (stationary phases, Chiralpak IG-3), column temperature (40°C), modifier types and concentration (isopropyl alcohol, 10%), additive types and concentrations (diethylamine, 0.2%), elution times (<6 min, flow rate 3 mL/min) and resolution factor (>1.2). These optimized conditions led to nicotine and nornicotine enantiomer detection limits of ~5 ng/μL with accompanying %RSD values of <2% from the analyses of commercially available nicotine-containing formulations.

Reliable biological indicator identification and evaluation of tobacco-derived nicotine using an ultra-sensitive gas chromatography-tandem mass spectrometric method

Several countries have exempted synthetic nicotine from existing regulatory frameworks, resulting in the widespread substitution of synthetic nicotine (SN) in almost all e-cigarette products available. However, it remains uncertain whether the purported synthetic nicotine is indeed genuine SN. There is a need to develop biological indicators and an analytical method that more clearly distinguishes between the two sources. Impurities in neat tobacco-derived nicotine (TDN) were characterized and identified through non-targeted and targeted analysis. Gas chromatography-tandem mass spectrometry (GC-MS/MS) conditions were optimized for detecting biological indicators in e-cigarette products. Nine tobacco-related alkaloids were identified and selected as biological indicators for TDN. A liquid-liquid extraction and GC-MS/MS quantitative method were developed to detect nine biological indicators in e-cigarette products with the limit of quantification ranging from 0.2 to 4.2 µg L-1 using 0.5 mL of e-liquid. This method was applied to 50 e-cigarette brands purchased in the Korean market. The developed method was able to easily and accurately identify the origin of nicotine even using a small amount of e-liquid sample. It is expected that effective e-cigarette regulation will be possible if the nicotine biological indicator and high-sensitivity analysis method developed in this study are used.

Tobacco-derived and tobacco-free nicotine cause differential inflammatory cell influx and MMP-9 in mouse lung

BACKGROUND

Electronic nicotine delivery systems (ENDS) or electronic cigarettes (e-cigarettes) aerosolize an e-liquid composed of propylene glycol (PG) and vegetable glycerin (VG) as humectants, flavoring chemicals, and nicotine. Nicotine naturally occurs in two isomers R- and S-nicotine, with tobacco-derived nicotine (TDN) composed of S-nicotine, and tobacco-free/synthetic nicotine (TFN) composed of a racemic mixture of R- and S-nicotine. Currently, there is limited knowledge of the potential differences in the toxicity of TFN versus TDN. We hypothesized that exposure of TFN and TDN salts to C57BL/6J mice would result in a differential response in lung inflammation and protease/ antiprotease imbalance.

METHODS

Five-week-old male and female C57BL/6J mice were exposed to air, PG/VG, PG/VG with TFN salts (TFN), or PG/VG with TDN salts (TDN) by nose-only exposure. Lung inflammatory cell counts, cytokine/chemokine levels, and matrix metalloproteinase (MMP) protein abundance and activity levels were determined by flow cytometry, ELISA, immunoblotting, and gel zymography, respectively.

RESULTS

Exposure to the humectants (PG/VG) alone increased cytokine levels- IL-6, KC, and MCP-1 in the BALF and KC levels in lung homogenate of exposed mice. While no change was observed in the cytokine levels in lung homogenate of TDN aerosol exposed mice, exposure to TFN aerosols resulted in an increase in KC levels in the lungs of these mice compared to air controls. Interestingly, exposure to TDN aerosols increased MMP-9 protein abundance in the lungs of female mice, while exposure to TFN aerosol showed no change. The metabolism of nicotine or the clearance of cotinine for TFN exposure may differ from that for TDN.

CONCLUSION

Exposure to humectants, PG/VG alone, induces an inflammatory response in C57BL/6J mice. TFN and TDN salts show distinct changes in inflammatory responses and lung proteases on acute exposures. These data suggest variable toxicological profiles of the two forms of nicotine in vivo. Future work is thus warranted to delineate the harmful effects of synthetic/natural nicotine with humectants to determine the potential toxicological risks for users.

Tobacco-Derived and Tobacco-Free Nicotine cause differential inflammatory cell influx and MMP9 in mouse lung

Electronic nicotine delivery systems (ENDS) or electronic cigarettes (e-cigarettes) have propylene glycol (PG) and vegetable glycerin (VG) as humectants, flavoring chemicals, and nicotine. Nicotine naturally occurs in two isomers R- and S-nicotine, with both tobacco-derived nicotine (TDN) composed of S-nicotine and synthetic nicotine (TFN) composed of a racemic mixture of R- and S-nicotine. Currently there is limited knowledge of the potential differences in the toxicity of TFN vs TDN. We hypothesized that exposure of TFN salts to C57BL/6J mice will result in a differential response in inflammation and lung protease and antiprotease imbalance compared to TDN salts exposed mice. We studied the toxicological impact of these isomers by exposing mice to air, PG/VG, PG/VG with TFN salts, or PG/VG with TDN salts by nose-only exposure and measured the cytokine levels in BALF and lung homogenate along with MMP protein abundance in the lungs of exposed mice. Exposure to the humectants, PG/VG, used in e-cigarettes alone was able to increase cytokine levels-IL-6, KC, and MCP-1 in BALF and KC levels in lung homogenate. Further, it showed differential responses on exposure to PG/VG with TDN salts and PG/VG with TFN salts since PG/VG with TDN salts did not alter the cytokine levels in lung homogenate while PG/VG with TFN salts resulted in an increase in KC levels. PG/VG with TDN salts increased the levels of MMP9 protein abundance in female exposed mice, while PG/VG with TFN salts did not alter MMP9 levels in female mice. The metabolism of nicotine or the clearance of cotinine from TFN may differ from the metabolism of nicotine or the clearance of cotinine from TDN. Thus exposure of humectants alone to induce an inflammatory response while PG/VG with TFN salts and PG/VG with TDN salts may differentially alter inflammatory responses and lung proteases in acute exposures. These data suggest the harmful effects of synthetic/natural nicotine and PG/VG and potential toxicological risk for users.

Quick nic: novel smokeless nicotine products and pediatric trends

PURPOSE OF REVIEW

The development and marketing of smokeless nicotine products in recent years have become increasingly popular among adolescents. In addition to well known conventional inhaled nicotine products, noninhaled products, such as nicotine toothpicks, orbs, lozenges, strips, and more, have dangerously captivated a new youth audience. Although smokeless nicotine products may seem to be less threatening than conventional inhaled nicotine products, there are significant risks associated with the use of these products, including addiction and severe health issues. The purpose of this review is to provide up-to-date information about alternative nicotine products currently on the market that may appeal to youth, and the dangers of nicotine use for pediatric populations.

RECENT FINDINGS

Smokeless nicotine products appeal to minors with their varying flavors and discrete packaging. These products may lead to nicotine toxicity as well as severe health problems, such as cancer, issues with reproduction, and heart attacks. Nicotine is extremely dangerous for young children; in fact, using nicotine products before the age of 18 years can lead to addiction and is linked to an increased likelihood of experimenting with stronger nicotine products or illicit drugs. The development of inconspicuous nicotine packaging has led to increasing concerns for accidental nicotine exposure and overdose in youth.

SUMMARY

Greater knowledge regarding current nicotine products on the market, specifically smokeless nicotine products, will help clinicians be more aware of the dangers associated with these products. Clinicians will be better able to provide their patients and families with proper guidance to avoid nicotine addiction, further drug use, and detrimental health issues. Caregivers and medical professionals must recognize novel and inconspicuous nicotine products commonly used among youth, understand the signs of nicotine abuse and dependence, and take measures to address possible nicotine-related health risks.

Synthetic nicotine e-liquids sold in US online vape shops

Synthetic nicotine (relative to tobacco-derived, or "natural" nicotine) is an emerging feature of e-cigarettes including e-liquids in the online marketplace. This study investigated a total of 11,161 unique nicotine e-liquids sold in online stores in the US during 2021, using keyword matching approach to identify the feature of synthetic nicotine based on product description texts. We showed that in 2021, 2.13% of nicotine-containing e-liquids in our sample were marketed as synthetic nicotine e-liquids. About a quarter of the synthetic nicotine e-liquids that we identified were salt-based; the nicotine strength varied; and those synthetic nicotine e-liquids had a variety of flavor profiles. Synthetic nicotine containing e-cigarettes are likely to remain in the market and manufacturers might market those products as "tobacco-free," to attract consumers who this feature as healthier or less addictive. It is important to monitor synthetic nicotine in the e-cigarette marketplace and assess how this feature influences consumer behaviors.

A Systematic Review of Analytical Methods for the Separation of Nicotine Enantiomers and Evaluation of Nicotine Sources

The introduction of synthetic nicotine by the tobacco industry, also promoted as tobacco-free nicotine, presented new challenges for analytical chemists working in tobacco regulatory science to develop and optimize new methods to assess new nicotine parameters, namely enantiomer ratio and source. We conducted a systematic literature review of the available analytical methods to detect the nicotine enantiomer ratio and the source of nicotine using PubMed and Web of Science databases. Methods to detect nicotine enantiomers included polarimetry, nuclear magnetic resonance, and gas and liquid chromatography. We also covered methods developed to detect the source of nicotine either indirectly via determining the nicotine enantiomer ratio or the detection of tobacco-specific impurities or directly using the isotope ratio enrichment analysis by nuclear magnetic resonance (site-specific natural isotope fractionation and site-specific peak intensity ratio) or accelerated mass spectrometry. This review presents an accessible summary of all these analytical methods.

Classification, Perception, and Toxicity of Emerging Flavored Oral Nicotine Pouches

INTRODUCTION

Oral Nicotine Pouches (ONPs) are the new form of nicotine pouches that have become a type of emerging smokeless tobacco product sold by various tobacco companies. These smokeless tobacco products are marketed for usage all over as snus containing tobacco-derived nicotine (natural) or as tobacco-free nicotine (synthetic) as substitutes for other tobacco products. Based on perception and socio-behavioral aspects, ONPs have become popular tobacco products among adolescents/young adults, and over 50% of young adult users of ONP use flavored ONPs, such as menthol/mint, tobacco, dessert/candy, and fruity, which are the most popular flavors. Various new ONP flavors are currently popular locally as well as in the online market. Tobacco, menthol, and fruit-flavored ONPs could motivate cigarette smokers to change to ONPs.

METHODS

We expanded our knowledge on natural/synthetic ONP flavor wheels to available data on ONPs, describing, in detail, their flavors and brands (US and Europe) in both natural and synthetic ONP categories. We classified over 152 snus and 228 synthetic ONPs into the following flavor categories: "Tobacco", "Menthol/Mint", "Fruity", "Candy/Deserts", "Drink", "Aroma", "Spices", and "Mixed Flavors".

RESULTS

Based on total numbers, we found the most popular ONP flavors, sold as tobacco and menthol, to be among natural ONPs; among synthetic ONPs, fruity and menthol are the most prominent flavors, with varying concentrations of nicotine and other flavoring chemicals, including coolant WS-23. We also showed possible molecular targets and toxicities, due to exposure to ONPs, activating several signaling cascades such as AKT and NF-kappaB, which might possibly lead to apoptosis and epithelial mesenchymal transition (EMT).

CONCLUSIONS

Considering the marketing of ONP products with various flavor profiles and with most of these products containing tobacco/menthol/fruit flavor, it is likely to have regulation and a marketing disclaimer on some of these products. Further, it would be logical to determine how the market reacts in terms of compliance and non-compliance with flavor restrictions by the regulatory agencies.

Stable isotope characterization of tobacco products: A determination of synthetic or natural nicotine authenticity

RATIONALE

"Tobacco-free" or synthetic nicotine products have appeared in some markets, increasing potential health risks and regulatory compliance challenges. Currently, there are few reliable methods for the determination of authenticity of natural and synthetic nicotine. Analytical techniques based on stable isotopes have broad application prospects in the traceability and identification of agricultural products.

METHODS

Tobacco leaves from four main tobacco production regions in China and different types of tobacco products were extracted with n-hexane and 5% sodium hydroxide to obtain nicotine extracts. Subsequent stable isotope mass spectrometry was performed by analyzing δ² H, δ¹³ C, and δ¹⁵ N values of nicotine.

RESULTS

Firstly, results from a batch of 233 samples indicated stable isotopes were closely related to climate and geographical locations and provide a basis for a determination of the origin of tobacco leaves. In addition, the δ² H values had significant differences between natural and synthetic nicotine and the results indicate a δ² H value of -163.0‰ could be the threshold for assessing synthetic and natural nicotine. Finally, a total of 239 results further validated the δ² H value as a metric for source authentication of commercial tobacco products.

CONCLUSIONS

Synthetic (S)-(-)-nicotine could be accurately and quickly identified using the method developed by measuring δ² H values in a qualitative manner. To our knowledge, this is the first time a stable isotope mass spectrometry technique has been used for distinguishing the source of nicotine. This technique will aid in the accurate identification, labelling, and regulation of synthetic nicotine-based tobacco products.

Emerging Oral Nicotine Products and Periodontal Diseases

Oral nicotine pouches are emerging as a new "modern oral" nicotine product. These prefilled pouches contain nicotine, flavorings, and filling agents that dissolve in the mouth. Nicotine can be derived from tobacco leaf or chemical synthesis. Traces of TSNAs and toxic chromium were detected in the pouch products. This raises the concern about general and periodontal health. This review aims to update the current oral nicotine products research relating to periodontal disease and its relevance in periodontal inflammation. Nicotine interacts with host cells and affects inflammatory responses to microbial challenges. It may directly or indirectly deteriorate periodontal tissues by activating nicotinic acetylcholine receptors, repressing PDL fibroblasts cells, increasing cellular ROS and cytokines/chemokines, growth factors, breaking microbiota balance, and dysregulating miRNAs expression. Studies show that appealing flavorings contained in nicotine pouches pose harm to periodontal innate immune responses and increase penetration of nitrosamines. In addition, flavored ONPs increase the risk of dual or poly-tobacco products among young adults, stacking up detrimental effects on the periodontium. Given the recent growth of users, further studies are needed to elucidate the impact of ONPs, even poly-tobacco use, on systemic and periodontal health. Moreover, policymakers should ensure to avoid generating a new wave of nicotine addiction among youths in the U.S.

Nicotine pouches: a summary of regulatory approaches across 67 countries

INTRODUCTION

Nicotine pouches are small, permeable pouches containing nicotine. The nicotine may either be derived from tobacco plants or synthetically produced. Nicotine pouches are available worldwide, but little is known as to how various countries regulate these products. This study summarises nicotine pouch regulatory policies across 67 countries.

METHODS

This research summarises insights obtained through active policy surveillance work in which we requested information on the availability of nicotine pouches and applicable policies and analysed responses from representatives of 67 countries (representatives included subject matter experts in government or civil society organisations). These countries span all WHO regions.

RESULTS

We found significant variation in how countries classify nicotine pouches, with many countries' current regulatory approach failing to regulate nicotine pouches that used synthetic nicotine. We found 34 countries regulate nicotine pouches with 23 of these countries' policies encompassing synthetic nicotine. Countries regulating both synthetic and tobacco-derived nicotine pouches generally (1) rely on existing policies for tobacco products and/or medicines or (2) have developed new policies or regulatory classifications that specify nicotine as the substance at issue rather than linking policies solely to tobacco.

CONCLUSION

Our work offers novel insight into nicotine pouch markets and national regulatory approaches. Policy approaches vary from not regulating nicotine pouches at all to banning both forms of nicotine pouches. Policies used by countries regulating both tobacco-derived and synthetic nicotine pouches offer a roadmap for how other jurisdictions can add effective guardrails to the use of these and other non-medicinal nicotine products.

Flavor Classification/Categorization and Differential Toxicity of Oral Nicotine Pouches (ONPs) in Oral Gingival Epithelial Cells and Bronchial Epithelial Cells

Oral nicotine pouches (ONPs) are a modern form of smokeless tobacco products sold by several brands in the U.S., which comprise a significant portion of non-combustible nicotine-containing product (NCNP) sales to date. ONPs are available in various flavors and may contain either tobacco-derived nicotine (TDN) or tobacco-free nicotine (TFN). The growth in popularity of these products has raised concerns that flavored ONPs may cause adverse oral health effects and promote systemic toxic effects due to nicotine and other ONP by-products being absorbed into the circulatory system through oral mucosa. We hypothesized that flavored ONPs are unsafe and likely to cause oral and pulmonary inflammation in oral and respiratory epithelial cells. Before analyzing the effects of ONPs, we first classified ONPs sold in the U.S. based on their flavor and the flavor category to which they belonged using a wheel diagram. Human gingival epithelial cells (HGEP) were treated with flavored ONP extracts of tobacco (original, smooth), menthol (wintergreen and cool cider), and fruit flavor (americana and citrus), each from the TDN and TFN groups. The levels of ONP-induced inflammatory cytokine release (TNF-α, IL-6, and IL-8) by ELISA, cellular reactive oxygen species (ROS) production by CellRox Green, and cytotoxicity by lactate dehydrogenase (LDH) release assay in HGEP cells were assessed. Flavored ONP extracts elicited differential toxicities in a dose- and extract-dependent manner in HGEP cells 24 h post-treatment. Both fruit TDN and TFN extracts resulted in the greatest cytotoxicity. Tobacco- and fruit-flavored, but not menthol-flavored, ONPs resulted in increased ROS production 4 h post-treatment. Flavored ONPs led to differential cytokine release (TNF-α, IL-6, and IL-8) which varied by flavor (menthol, tobacco, or fruit) and nicotine (TDN vs. TFN) 24 h post-treatment. Menthol-flavored ONPs led to the most significant TNF-α release; fruit TFN resulted in the most significant IL-6 release; and fruit TDN and tobacco TFN led to the highest release of IL-8. Subsequently, human bronchial epithelial cells (16-HBE and BEAS-2B) were also treated with flavored ONP extracts, and similar assays were evaluated. Here, the lowest concentration treatments displayed increased cytotoxicity. The most striking response was observed among cells treated with spearmint and tobacco flavored ONPs. Our data suggest that flavored ONPs are unsafe and likely to cause systemic and local toxicological responses during chronic usage.

Adolescents, Young Adults, and Adults Continue to Use E-Cigarette Devices and Flavors Two Years after FDA Discretionary Enforcement

This study assesses the use of e-cigarette devices and flavors using a large, cross-sectional survey of adolescents, young adults, and adults (N = 6131; ages 13−40 years old; Mage = 21.9) conducted from November to December 2021, 22 months after the FDA announced its prioritized enforcement policy against some flavored pod/cartridge-based e-cigarettes. We analyzed the patterns of use by age group: adolescents and young adults (AYAs) under 21 (minimum age of e-cigarette sales), young adults (21−24 years old), and adults (25−40 years old). The participants reported using e-cigarettes ever (44.2% < 21; 67.1% 21−24; 58.0% > 24), in the past 30 days (29.8% < 21; 52.6% 21−24; 43.3% > 24), and in the past 7 days (24.5% < 21; 43.9% 21−24; 36.5% > 24). Disposables were the most used e-cigarette device type across age groups (39.1% < 21; 36.9% 21−24; 34.5% > 24). Fruit, sweet, mint, and menthol flavors were popular across age groups; however, chi-squared tests for trends in proportions revealed age-related trends in past 30-day flavor use by device type. Findings suggest current AYA e-cigarette use may be higher than recorded by the NYTS 2021. The FDA, states, and localities should adopt more comprehensive restrictions on flavored e-cigarette products in order to reduce adolescent and young adult e-cigarette use.