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Objectives: To describe the effect of e-liquid flavors on nicotine intake and pharmacology of e-cigarettes.Methods: 11 males and 3 females participated in a 3-day inpatient crossover study with strawberry, tobacco, and their usual flavor e-liquid. Nicotine levels were nominally 18mg/mL in the strawberry (pH 8.29) and tobacco (pH 9.10) e-liquids and ranged between 3-18mg/mL in the usual brands (mean pH 6.80). Each day consisted of a 15-puff session followed by 4h of abstinence, then 90min of ad libitum use. Subjects used a KangerTech mini ProTank 3.Results: After 15 puffs, the amount of nicotine inhaled and systemically retained were not significantly different between the strawberry and tobacco e-liquids but plasma AUC(0→180) was significantly higher with the strawberry e-liquid. While not significantly different, Cmax was 22% higher and various early time point AUCs to measure rate of rise of nicotine in blood ranged between 17 and 23% higher with the strawberry e-liquid compared to the tobacco e-liquid. During ad libitum use, systemic exposure to nicotine (AUC(0→90)) was the same for the tobacco and usual brand e-liquids but were both significantly lower than after using the strawberry e-liquid. The usual flavors were more liked and satisfying than the strawberry and tobacco e-liquids.Conclusion: Flavors influence nicotine exposure through flavor liking, may affect rate of nicotine absorption possibly through pH effects, and contribute to heart rate acceleration and subjective effects of e-cigarettes. E-cigarette users titrate their nicotine exposure but the extent of titration may vary across flavors. [ABSTRACT FROM AUTHOR]

Background: Rate of nicotine metabolism is an important factor influencing cigarette smoking behavior, dependence, and efficacy of nicotine replacement therapy. The current study examined the hypothesis that chronic alcohol abuse can accelerate the rate of nicotine metabolism. Nicotine metabolite ratio (NMR, a biomarker for rate of nicotine metabolism) and patterns of nicotine metabolites were assessed at three time points after alcohol cessation.Methods: Participants were 22 Caucasian men randomly selected from a sample of 165 smokers entering a 7-week alcohol dependence treatment program in Poland. Data were collected at three time points: baseline (week 1, after acute alcohol detoxification), week 4, and week 7. Urine was analyzed for nicotine and metabolites and used to determine the nicotine metabolite ratio (NMR, a biomarker for rate of nicotine metabolism), and total nicotine equivalents (TNE, a biomarker for total daily nicotine exposure).Results and Conclusions: There was a significant decrease in urine NMR over the 7 weeks after alcohol abstinence (F(2,42)=18.83, p<0.001), indicating a decrease in rate of nicotine metabolism. On average NMR decreased 50.0% from baseline to week 7 (9.6±1.3 vs 4.1±0.6). There was no change in urine TNE across the three sessions, indicating no change daily nicotine intake. The results support the idea that chronic alcohol abuse may increase the rate of nicotine metabolism, which then decreases over time after alcohol cessation. This information may help to inform future smoking cessation interventions in this population. [ABSTRACT FROM AUTHOR]

Background: The Hooked on Nicotine Checklist (HONC) has been used to assess nicotine dependence (loss of autonomy over tobacco) among adolescents. Existing HONC validation studies for non-cigarette products, such as electronic cigarettes (e-cigarettes), have generally not considered biomarkers of nicotine exposure.Methods: Within a cross-sectional sample of California (USA) high school students (total N = 1396; mean age 15.2 years; 56% female; 54% Hispanic/Latinx), self-reported past 30-day users of any tobacco (including e-cigarettes) completed a modified 10-item HONC questionnaire and provided saliva samples (N = 318 samples, including N = 234 exclusive past 30-day e-cigarette users). Samples were analyzed for cotinine using liquid chromatography-tandem mass spectrometry (lower limit of quantification: 1.0 ng/mL).Results: Across four categories of HONC score corresponding to an increasing number of reported dependence symptoms (scores: 0, 1, 2-4, 5-10), the prevalence of quantifiable salivary cotinine increased among past 30-day tobacco users (20%, 21%, 38%, 55%, respectively, P-for-trend < 0.001) and among past 30-day exclusive e-cigarette users (15%, 22%, 31%, 42%, respectively, P-for-trend = 0.001). Among participants with quantifiable cotinine levels, HONC total score and cotinine were positively correlated among past 30-day tobacco users (n = 89; Spearman rho = 0.449; P < 0.001) and past 30-day exclusive e-cigarette users (n = 49; Spearman rho = 0.520; P < 0.001). HONC score was also associated with past 30-day frequency of tobacco product use and reported use of tobacco within 30 min of waking.Conclusions: These results support the validity of HONC to assess nicotine dependence among adolescents. Dependence symptoms may be experienced at low levels of nicotine exposure. [ABSTRACT FROM AUTHOR]

Increased interest in volatile organic compound (VOC) exposure has led to an increased need for consistent, systematic, and informative naming of VOC metabolites. As analytical methods have expanded to include many metabolites in a single assay, the number of acronyms in use for a single metabolite has expanded in an unplanned and inconsistent manner due to a lack of guidance or group consensus. Even though the measurement of VOC metabolites is a well-established means to investigate exposure to VOCs, a formal attempt to harmonize acronyms amongst investigators has not been published. The aim of this work is to establish a system of acronym naming that provides consistency in current acronym usage and a foundation for creating acronyms for future VOC metabolites. [ABSTRACT FROM AUTHOR]

Background: Blacks bear a disproportionate burden of smoking-related diseases and experience greater difficulty quitting smoking than Whites. Nicotine has a high affinity for melanin, and it has been hypothesized that melanin levels might influence nicotine pharmacokinetics and enhance dependence. The aim of this study was to evaluate the hypothesis that melanin affects nicotine disposition kinetics in humans.Methods: Forty-four Black participants were administered intravenous infusions of deuterium-labeled nicotine and cotinine. Plasma concentrations of nicotine and cotinine were measured, and pharmacokinetic parameters were estimated. The constitutive and facultative melanin indexes were measured using a dermaspectrophotometer.Results: The median constitutive melanin index was 60.7 (32.8-134.7) and the median facultative melanin index 68.1 (38.6-127.1). The mean (±SD) nicotine elimination half-life was 136 min (±33.5), clearance was 1237 mL/min (±331), and Vss was 204 L (±66), or 2.6 L/kg (±0.7). No evidence of significant differences was found in nicotine pharmacokinetic parameters by comparing participants in different melanin index quartiles (outliers with very high melanin index had similar pharmacokinetic values to others). Differences were not statistically significant when adjusted for age, BMI, sex and CYP2A6 genotype or the nicotine metabolite ratio (NMR), and no evidence of significant correlations were found between melanin (facultative or constitutive) and the pharmacokinetic parameters of nicotine or cotinine or tobacco dependence measures.Conclusions: Based on our finding in this group of Black smokers, we could not confirm the hypothesis that melanin significantly affects nicotine disposition kinetics or measures of tobacco dependence. [ABSTRACT FROM AUTHOR]