Chemical analysis of fresh and aged Australian e-cigarette liquids.

OBJECTIVES: To assess the chemical composition of electronic cigarette liquids (e-liquids) sold in Australia, in both their fresh and aged forms. DESIGN, SETTING: Gas chromatography-mass spectrometry analysis of commercial e-liquids sold in Australia (online and physical stores). MAIN OUTCOME MEASURES: Chemical composition of 65 Australian e-liquids - excipients/solvents, flavouring chemicals, other known e-liquid constituents (including nicotine), and polycyclic aromatic hydrocarbons - before and after an accelerated ageing process that simulated the effects of vaping. RESULTS: The measured levels of propylene glycol and glycerol often diverged from those recorded on the e-liquid label. All e-liquids contained one or more potentially harmful chemicals, including benzaldehyde, menthol, trans-cinnamaldehyde, and polycyclic aromatic hydrocarbons. Nicotine or nicotyrine were detected in a small proportion of e-liquids at extremely low concentrations. CONCLUSIONS: Australian e-liquids contain a wide variety of chemicals for which information on inhalation toxicity is not available. Further analyses are required to assess the potential long term effects of e-cigarette use on health.

Biocompatible SPME fibers for direct monitoring of nicotine and its metabolites at ultra trace concentration in rabbit plasma following the application of smoking cessation formulations.

The ultra-trace determination of nicotine and its 4 major metabolites (cotinine, nornicotine, norcotinine and anabasine) from rabbit plasma was achieved by a newly developed solid phase microextraction-liquid chromatography-tandem mass spectrometry method. Extraction of the target analytes was performed with hydrophilic/lipophilic balance-polyacrylonitrile SPME fibers. Dual fiber extraction was necessary to guarantee improved recovery at parts-per-trillion levels. Liquid chromatographic analysis was achieved in a 6-min run using a C18 (1.9 µm C18, 50 mm x 2.1 mm) column with a mobile phase flow rate of 0.4 mL/min. Tandem mass spectrometry was used for detection and quantification in positive electrospray ionization (ESI+) mode for all the targeted analytes. Two stable isotope-labeled internal standards were used for signal correction and accurate quantification. The mass spectrometer with laminar flow ion flux transport, guaranteed improved signal stability, minimal contamination of the ion guide and reproducibility into the first quadrupole analyzer. The method was validated in line with the Food and Drug Administration (FDA) guidelines for bioanalytical method validation. The results met the acceptance criteria as proposed by the FDA: accuracy was tested at 0.35, 10 and 75 µg L - 1 and ranged between 98.3-112.2% for nicotine, 94.1-101.9% for cotinine, 94.7-107.0% for nornicotine, 81.1-107.2% for norcotinine and 94.3-115.2% for anabasine, with precision up to 14.2%. Stability tests indicated that all the targeted analytes were stable in the desorption solution for at least 1 week. LOQs ranged from 0.05 to 1 µg L-1. The method was successfully applied to analyze plasma samples obtained from rabbits following transdermal application of a smoking cessation formulation loaded with solid lipid nanoparticles containing a nicotine-stearic acid conjugate.

Mouth-Level Nicotine Intake Estimates from Discarded Filter Butts to Examine Compensatory Smoking in Low Nicotine Cigarettes.

BACKGROUND: A mandated reduction in the nicotine content of cigarettes could reduce smoking rate and prevalence. However, one concern is that smokers may compensate by increasing the intensity with which they smoke each cigarette to obtain more nicotine. This study assessed whether smokers engage in compensatory smoking by estimating the mouth-level nicotine intake of low nicotine cigarettes smoked during a clinical trial. METHODS: Smokers were randomly assigned to receive cigarettes with one of five nicotine contents for 6 weeks. An additional group received a cigarette with the lowest nicotine content, but an increased tar yield. The obtained mouth-level nicotine intake from discarded cigarette butts for a subset of participants (51-70/group) was estimated using solanesol as described previously. A compensation index was calculated for each group to estimate the proportion of nicotine per cigarette recovered through changes in smoking intensity. RESULTS: There was no significant increase in smoking intensity for any of the reduced nicotine cigarettes as measured by the compensation index (an estimated 0.4% of the nicotine lost was recovered in the lowest nicotine group; 95% confidence interval, -0.1 to 1.2). There was a significant decrease in smoking intensity for very low nicotine content cigarettes with increased tar yield. CONCLUSIONS: Reductions in nicotine content did not result in compensatory changes in how intensively participants smoked research cigarettes. IMPACT: Combined with data from clinical trials showing a reduction in cigarettes smoked per day, these data suggest that a reduction in nicotine content is unlikely to result in increased smoke exposure.

The Impact of Exclusive Use of Very Low Nicotine Cigarettes on Compensatory Smoking: An Inpatient Crossover Clinical Trial.

BACKGROUND: The FDA is considering a mandated reduction in the nicotine content of cigarettes. Clinical trials have been limited by non-study cigarette use (noncompliance), which could mask compensation. The goal of this study was to assess whether compensation occurs when smokers provided with very low nicotine cigarettes cannot access normal nicotine cigarettes. METHODS: In a within-subjects, crossover design, current smokers (n = 16) were confined to a hotel for two 4-night hotel stays during which they were only able to access the research cigarettes provided. The hotel stays offered normal nicotine cigarettes or very low nicotine content (VLNC) cigarettes, in an unblinded design, available for "purchase" via a study bank. RESULTS: In the context of complete compliance with the study cigarettes (n = 16), there was not a significant increase during the VLNC condition for cigarettes smoked per day, expired carbon monoxide, or N-acetyl-S-(cyanoethyl)-l-cysteine (cyanoethyl-MA, metabolite of acrylonitrile). There was a significant nicotine × time interaction on urine N-acetyl-S-(3-hydroxypropyl)-l-cysteine (hydroxypropyl-MA, metabolite of acrolein), driven by an increase in the VLNC condition during the first 24 hours. By the end of the VLNC condition, there was no evidence of compensation across any measure of smoking or smoke exposure. CONCLUSIONS: Among current smokers who exclusively used VLNC cigarettes for 4 days, there was no significant compensatory smoking behavior. IMPACT: These data, combined with the larger body of work, suggest that a mandated reduction in nicotine content is unlikely to result in an increase in smoking behavior to obtain more nicotine.

A Procedure to Standardize Puff Topography During Evaluations of Acute Tobacco or Electronic Cigarette Exposure.

INTRODUCTION: Documenting factors that influence differential sensitivity to acutely inhaled nicotine products requires carefully controlling the amount of exposure (dose), and thus a procedure by which to control such exposure. METHODS: We evaluated consistency of puff volume from intermittent acute exposures to smoked tobacco cigarettes (study 1, n = 45, plus a comparison study of uninstructed use with n = 59) and to vaped electronic cigarettes (e-cigarettes; study 2, n = 27 naive to e-cigarettes) in adult-dependent smokers. All in primary studies 1 and 2 participated in research administering different nicotine levels in each product under blind conditions, one per session using within-subject designs. In both studies, participants followed an automated instructional procedure on a computer monitor standardizing the timing and amount of exposure to each product during a given trial, with four trials per session, each separated by 20 minutes. Puff volume per trial via Clinical Research Support System (CReSS) was the primary dependent measure to determine consistency across trials via intraclass correlation coefficients (ICCs). RESULTS: Control over topography with both inhaled products was demonstrated by highly significant ICCs for puff volume across trials. Instructed control with own brand was generally better in study 1 than with uninstructed smoking in the comparison sample, as expected. As intended, reliability of puff volume generally did not differ by menthol preference or sex in either study, but ICCs in study 2 tended to be lower for some men using the placebo e-cigarette. CONCLUSIONS: This instructional procedure may substantially improve control over amounts of acute exposure to tobacco or e-cigarette use. IMPLICATIONS: Control over topography in studies of acute exposure to these inhaled products can potentially aid validity of research into differential sensitivity to use, so findings can be attributed to factors of interest and not to variable exposure. Our procedure minimized variability in exposure to the same product and between moderate nicotine products, but remaining differences suggest that compensation for very low or no nicotine commercial products may be difficult to totally eliminate with these instructions alone. Further study is needed to determine this procedure's utility with other inhaled products among experienced users and when comparing different products in between-groups analyses.

Development and Piloting Testing of an Experimental Tobacco and Nicotine Product Marketplace.

INTRODUCTION: We describe the development and pilot testing of the experimental tobacco and nicotine product marketplace (ETM)-a method for studying tobacco and nicotine product (TNP) choices and use behavior in a standardized way. AIMS AND METHODS: The ETM resembles an online store populated with TNPs. Surveillance activities and data from a US representative survey and consumer reports were used to determine the most popular TNPs for inclusion in the ETM. Standardized information and videos demonstrating how to use the TNPs were provided. To test the feasibility of using the ETM, smokers (n = 119) underwent monitoring of usual brand cigarette smoking and other TNP use (Baseline Phase) followed by access to the ETM (ETM Phase) that included their usual brand cigarettes, e-cigarettes, moist snuff, snus, and nicotine replacement therapy. During the ETM Phase, participants were provided points based on their baseline TNP consumption to exchange for TNPs in the ETM. Participants were advised to exchange points for enough TNPs to last until their next visit and to refrain from using TNPs not obtained in the ETM. A subset of the participants (n = 62) completed a survey on their experience with the ETM. RESULTS: The majority of the participants stated they were comfortable with navigating the ETM (97%), it was easy to determine product characteristics (89%), and they were satisfied with the products included in the marketplace (85%). CONCLUSIONS: The ETM was well received by the vast majority of the participants and can be utilized by researchers to investigate a variety of TNP policy and regulatory science research questions. IMPLICATIONS: Patterns of TNP use are complex due to greater availability, marketing, and promotion of a diverse array of TNPs. Innovative methods are needed to experimentally study TNP choices and patterns. Through describing the development of the ETM, we provide researchers with a tool that can be readily adapted to studying a variety of phenomena challenging public health.

Research on Behavioral Discrimination of Nicotine May Inform FDA Policy on Setting a Maximum Nicotine Content in Cigarettes.

INTRODUCTION: The Food and Drug Administration may set a maximum nicotine content in cigarettes to minimize smoking's addictiveness. Our recent research may indirectly support setting levels applicable to the population of dependent smokers below 1 mg/g (mg nicotine/g of tobacco filler). METHODS: Using a within-subjects design in laboratory-based studies totaling 61 nontreatment seeking adult dependent smokers, Spectrum research cigarettes with nicotine contents ranging from 1.3 to 17 mg/g (just one per session) were compared with the lowest content available, 0.4 mg/g. Identified for each participant was the smallest difference in nicotine content, or "threshold," between cigarettes that still supported behavioral discrimination (ie, ability to objectively distinguish their difference). The next lower nicotine content cigarette, not discriminated (by definition), was labeled their "subthreshold." Subjective perceptions and choice behavior were also assessed. RESULTS: Thresholds varied widely among all 61 smokers but, importantly, fewer than 7% of smokers could discriminate the two lowest, 1.3 versus 0.4 mg/g nicotine, meaning more than 90% could not do so. Moreover, we found a consistent association between their nicotine discrimination threshold and their subjective perceptions and subsequent reinforcement behavior later in the session. Specifically, a participant's discrimination threshold cigarette was also more highly rated and preferred (ie, self-administered), whereas their subthreshold cigarette was rated similarly to the 0.4 mg/g and not preferred. CONCLUSIONS: Cigarette nicotine content below the threshold for perceiving nicotine's effects (ie, its discriminability) in nearly all smokers from a no nicotine comparison is likely below 1.0 mg/g, or less than or equal to 10% of that in typical commercial cigarettes. IMPLICATIONS: Cigarettes with nicotine contents able to be discriminated (threshold) are also reinforcing, and those unable to be discriminated are not reinforcing, as anticipated. Yet, research explicitly comparing cigarettes with contents below 1.0 mg/g versus no nicotine (ie, a "placebo") is needed with larger samples. Results may confirm what nicotine content lower than 1.0 mg/g is below the threshold for discrimination (and self-administration) in the vast majority (>95%) of adult dependent smokers as well as teens beginning to smoke. Identifying that content would strongly support the Food and Drug Administration policy to establish a maximum nicotine content in cigarettes that will not maintain dependence.

The Importance of Estimating Causal Effects for Evaluating a Nicotine Standard for Cigarettes.

Recent evidence from randomized clinical trials (RCTs) of very low nicotine content (VLNC) cigarettes indicates that smokers randomized to VLNC cigarettes had significantly lower cigarette use, dependence, and biomarkers of exposure than smokers randomized to normal nicotine content control cigarettes. In these trials, a substantial number of participants did not adhere to their randomized treatment assignment, i.e., they used commercial cigarettes not provided by the trial in place of or in addition to the VLNC cigarettes provided by the trial. As with most RCTs, the analysis of these trials followed the intention-to-treat principle, where participants are analyzed according to their randomized treatment assignment regardless of adherence. Alternately, the analysis of an RCT could focus on the estimation and testing of the causal effect of the intervention, which is the treatment effect if all subjects were to adhere to their randomized treatment assignment. In this commentary, we compare these two approaches, highlighting the important role of causal estimation and inference for evaluating the regulatory effect of a nicotine standard for cigarettes. Additionally, we review the results of the secondary analyses of randomized trials of VLNC cigarettes using causal inference methodology to account for non-adherence to the assigned treatment and discuss the implications for a nicotine standard for cigarettes.

U.S. Adults' Attitudes Toward Lowering Nicotine Levels in Cigarettes.

INTRODUCTION: This study assessed U.S. adults' attitudes toward lowering the nicotine levels in cigarettes to make them less addictive. METHODS: Data from the 2018 SummerStyles, a web-based panel survey of U.S. adults aged ≥18 years (n=4,037) fielded in June-July, were analyzed in 2018. Respondents were asked: Do you favor or oppose requiring cigarette makers to lower the nicotine levels in cigarettes so that they are less addictive? Responses were strongly favor, somewhat favor, somewhat oppose, and strongly oppose. Sociodemographic correlates of favorability (strongly favor or somewhat favor) were assessed using multivariable Poisson regression. RESULTS: Eighty-one percent of adults in 2018 strongly or somewhat favored requiring cigarette makers to lower the nicotine levels in cigarettes to make them less addictive, including 80.6% of current cigarette smokers, 84.3% of former smokers, and 81.3% of never smokers. Favorability was 71.5% among current noncigarette tobacco product users and 81.9% among nonusers. Following adjustment, slight variations in favorability existed by sex, age, race/ethnicity, and other tobacco product use. CONCLUSIONS: Most adults favor requiring cigarette makers to lower the nicotine levels in cigarettes, including 8 in 10 current cigarette smokers. These findings can help inform the U.S. Food and Drug Administration's recent proposal to pursue a nicotine reduction standard for cigarettes.

Basic Science and Public Policy: Informed Regulation for Nicotine and Tobacco Products.

Introduction: Scientific discoveries over the past few decades have provided significant insight into the abuse liability and negative health consequences associated with tobacco and nicotine-containing products. While many of these advances have led to the development of policies and laws that regulate access to and formulations of these products, further research is critical to guide future regulatory efforts, especially as novel nicotine-containing products are introduced and selectively marketed to vulnerable populations. Discussion: In this narrative review, we provide an overview of the scientific findings that have impacted regulatory policy and discuss considerations for further translation of science into policy decisions. We propose that open, bidirectional communication between scientists and policy makers is essential to develop transformative preventive- and intervention-focused policies and programs to reduce appeal, abuse liability, and toxicity of the products. Conclusions: Through these types of interactions, collaborative efforts to inform and modify policy have the potential to significantly decrease the use of tobacco and alternative nicotine products and thus enhance health outcomes for individuals. Implications: This work addresses current topics in the nicotine and tobacco research field to emphasize the importance of basic science research and provide examples of how it can be utilized to inform public policy. In addition to relaying current thoughts on the topic from experts in the field, the article encourages continued efforts and communication between basic scientists and policy officials.

A Survey of Nicotine Yields in Small Cigar Smoke: Influence of Cigar Design and Smoking Regimens.

Introduction: Although the popularity of small cigar brands that resemble cigarettes, including both little cigars (LC) and filtered cigars (FC), has been on the rise, little is known about the delivery of nicotine from these products. Our objective was to determine the nicotine yields of small cigars in comparison to cigarettes. Methods: Nicotine yields from LC, FC, and 3R4F and 1R6F research cigarettes were determined from mainstream smoke generated on a smoking machine under the International Organization of Standardization (ISO) and Canadian Intense (CI) methods. Market characteristics (price and package label) and physical features (filter ventilation, product weight and filter weight, product length, and diameter) were also determined for eight brands of small cigars. Results: Nicotine yields in small cigars averaged 1.24 and 3.49 mg/unit on ISO and CI regimens, respectively, compared with 0.73 and 2.35 mg/unit, respectively, for the research cigarettes. Nicotine yields per puff were similar between small cigars and cigarettes. We also found that FC did not differ from LC in nicotine yields. FC and LC differ from each other in many physical design features (unit weight, filter weight, and filter length), but are similar in others (unit length, diameter, and filter ventilation). Conclusions: Nicotine delivery from small cigars is similar to or greater than that from cigarettes. Thus, for future research and regulatory purposes, standard definitions need to be developed for small cigars, and FC and LC should be evaluated as separate entities. Implications: Small cigars are similar to cigarettes in their design and use. Although nicotine yields per puff were similar between products, small cigars delivered substantially higher amounts of nicotine per unit than cigarettes. These findings support the growing body of evidence to justify regulating all small cigars, including LC and FC in a similar fashion as cigarettes.

Development of a Cigarette Tobacco Filler Standard Reference Material.

A new tobacco filler Standard Reference Material (SRM) has been issued by the National Institute of Standards and Technology (NIST) in September 2016 with certified and reference mass fraction values for nicotine, N-nitrosonornicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, and volatiles. The constituents have been determined by multiple analytical methods with measurements at NIST and at the Centers for Disease Control and Prevention, and with confirmatory measurements by commercial laboratories. This effort highlights the development of the first SRM for reduced nicotine and reduced tobacco-specific nitrosamines with certified values for composition.

Multivariate Statistical Analysis of Cigarette Design Feature Influence on ISO TNCO Yields.

The aim of this study is to explore how differences in cigarette physical design parameters influence tar, nicotine, and carbon monoxide (TNCO) yields in mainstream smoke (MSS) using the International Organization of Standardization (ISO) smoking regimen. Standardized smoking methods were used to evaluate 50 U.S. domestic brand cigarettes and a reference cigarette representing a range of TNCO yields in MSS collected from linear smoking machines using a nonintense smoking regimen. Multivariate statistical methods were used to form clusters of cigarettes based on their ISO TNCO yields and then to explore the relationship between the ISO generated TNCO yields and the nine cigarette physical design parameters between and within each cluster simultaneously. The ISO generated TNCO yields in MSS are 1.1-17.0 mg tar/cigarette, 0.1-2.2 mg nicotine/cigarette, and 1.6-17.3 mg CO/cigarette. Cluster analysis divided the 51 cigarettes into five discrete clusters based on their ISO TNCO yields. No one physical parameter dominated across all clusters. Predicting ISO machine generated TNCO yields based on these nine physical design parameters is complex due to the correlation among and between the nine physical design parameters and TNCO yields. From these analyses, it is estimated that approximately 20% of the variability in the ISO generated TNCO yields comes from other parameters (e.g., filter material, filter type, inclusion of expanded or reconstituted tobacco, and tobacco blend composition, along with differences in tobacco leaf origin and stalk positions and added ingredients). A future article will examine the influence of these physical design parameters on TNCO yields under a Canadian Intense (CI) smoking regimen. Together, these papers will provide a more robust picture of the design features that contribute to TNCO exposure across the range of real world smoking patterns.

Randomized Trial of Reduced-Nicotine Standards for Cigarettes.

BACKGROUND: The Food and Drug Administration can set standards that reduce the nicotine content of cigarettes. METHODS: We conducted a double-blind, parallel, randomized clinical trial between June 2013 and July 2014 at 10 sites. Eligibility criteria included an age of 18 years or older, smoking of five or more cigarettes per day, and no current interest in quitting smoking. Participants were randomly assigned to smoke for 6 weeks either their usual brand of cigarettes or one of six types of investigational cigarettes, provided free. The investigational cigarettes had nicotine content ranging from 15.8 mg per gram of tobacco (typical of commercial brands) to 0.4 mg per gram. The primary outcome was the number of cigarettes smoked per day during week 6. RESULTS: A total of 840 participants underwent randomization, and 780 completed the 6-week study. During week 6, the average number of cigarettes smoked per day was lower for participants randomly assigned to cigarettes containing 2.4, 1.3, or 0.4 mg of nicotine per gram of tobacco (16.5, 16.3, and 14.9 cigarettes, respectively) than for participants randomly assigned to their usual brand or to cigarettes containing 15.8 mg per gram (22.2 and 21.3 cigarettes, respectively; P<0.001). Participants assigned to cigarettes with 5.2 mg per gram smoked an average of 20.8 cigarettes per day, which did not differ significantly from the average number among those who smoked control cigarettes. Cigarettes with lower nicotine content, as compared with control cigarettes, reduced exposure to and dependence on nicotine, as well as craving during abstinence from smoking, without significantly increasing the expired carbon monoxide level or total puff volume, suggesting minimal compensation. Adverse events were generally mild and similar among groups. CONCLUSIONS: In this 6-week study, reduced-nicotine cigarettes versus standard-nicotine cigarettes reduced nicotine exposure and dependence and the number of cigarettes smoked. (Funded by the National Institute on Drug Abuse and the Food and Drug Administration Center for Tobacco Products; ClinicalTrials.gov number, NCT01681875.).