Introduction Many electronic cigarette manufacturers have begun offering liquids containing “nicotine salts,” which are formed when an acid is mixed in a solution with free-base nicotine. Type of salt could play a significant role in the abuse liability of electronic cigarette liquids. As a first step to understanding nicotine salts, this study sought to identify the types of acids present in 23 commercially available electronic cigarette liquids. Aims and Methods Twenty-three electronic cigarette liquids advertised as containing nicotine salts were purchased for analysis. These liquids were tested for the presence of 11 different organic acids that were deemed likely to be used in a nicotine salt formulation. Liquids were analyzed using a combination of liquid chromatography–mass spectrometry and gas chromatography–mass spectrometry methods, then compared to authentic acid standards for identification. Results Six of the 11 possible acids were identified in the liquids, from most to least common: lactic, benzoic, levulinic, salicyclic, malic, and tartaric acid. Acid(s) could not be identified in one of the liquids. Though most liquids contained only one type, three of the liquids contained multiple acids. Conclusions These data demonstrate that several types of salts/acids are currently being used in electronic cigarette liquids. The type and concentration of salt(s) used in these liquids may differentially alter sensations in the throat and upper airway, and overall pharmacology of the aerosols by altering liquid pH and from flavor and sensory characteristics of the acids themselves. Implications This study demonstrates that at least six different types of acids are being used to create the nicotine salts in electronic cigarette liquids, with the acids lactic, benzoic, and levulinic being the most frequently identified. Identification of these acids can serve as the foundation for future research to determine if type of nicotine salt alters pharmacological and toxicological effects of electronic cigarettes.

No abstract

Previous research has shown a relationship between impulsive personality and the subjective and reinforcing effects of d-amphetamine. Impulsive personality, however, is comprised of multiple dimensions. The association between different dimensions of impulsive personality and the subjective and reinforcing effects of d-amphetamine is unknown. The objective of this study was to assess the independent contributions of the “sensation-seeking” and “impulsivity” dimensions of the impulsive sensation-seeking subscale of the Zuckerman-Kuhlman Personality Questionnaire (ZKPQ) to the subjective and reinforcing effects of d-amphetamine. Forty healthy emerging adults varying in scores on the sensation-seeking and impulsivity dimensions of the ZKPQ participated in a double-blind, placebo-controlled, randomized study comprised of four two-day blocks. Each two-day block consisted of a sample day and self-administration day. Subjective effects and physiological measurements were taken prior to, and hourly for 3 h following, dose administration. On sample days participants were given eight capsules containing 0, 1, or 2 mg d-amphetamine. On self-administration days participants were able to earn capsules containing the same dose of d-amphetamine that was administered on the previous sample day by responding on a Modified Progressive Ratio Task. The “sensation-seeking” dimension was positively associated with drug taking on the Modified Progressive Ratio Task, subjective effects (e.g. ‘good effect’), and heart rate. However, no clear relationship between the “impulsivity” dimension and outcome measures was observed. In conclusion, these data suggest that the narrow sensation-seeking dimension of impulsive sensation-seeking is associated with initial drug liking and drug taking behavior and may be a key predictor of drug use initiation.

Background: Behavioral measures of impulsive behavior include the dimensions of behavioral disinhibition, decision-making, and lapses of attention. These behaviors are associated with a range of risky activities during adolescence, including cigarette smoking; however, few studies have evaluated their associations with tobacco treatment outcomes. The current study examined the relationship between impulsive behavior and contingency management treatment outcomes for adolescent smokers. Methods: Data from two contingency management smoking cessation trials were combined (N = 189 adolescents). Participants provided breath carbon monoxide (CO) samples with incentives delivered contingent (i.e., active treatment [AT] condition) or non-contingent (i.e., control treatment [CT] condition) on CO level. Dimensions of impulsive behavior were assessed pre-and post-treatment using the Go/Stop Task, a measure of delay discounting, a continuous performance task, while self-reported impulsivity was assessed with the Barratt Impulsiveness Scale-Adolescent. Relationships between impulsive behavior and treatment outcomes (efficacy and adherence) were assessed using linear mixed effects models. Results: Participants in the AT condition had significantly lower program CO levels at each treatment phase. Delay discounting in the AT condition predicted CO levels, with those discounting the most lowering their breath CO levels the least. Delay discounting also predicted program adherence across both conditions. Conclusions: Delay discounting may be the most relevant dimension of impulsive behavior to predict outcomes for adolescent smokers completing CM programs, both in terms of successful reductions in smoking and program adherence. Suggestions are made to reduce the effects of delay discounting for adolescent smokers using this treatment approach.

Background and Aims Relative pharmacological effects of e-cigarettes and cigarettes during 24 hours of ad-libitum use have not been described. In this study, 24-hour blood plasma nicotine concentrations and 48-hour subjective effects with use of cigarettes and e-cigarettes were measured among dual users. Design Two-arm within-subject cross-over design with preferred e-cigarette or cigarette ad-libitum use over 48 hours. Setting Hospital research ward in San Francisco, California, USA. Participants Thirty-six healthy dual users of e-cigarettes and cigarettes (n = 8, 25% females). Measurements Twenty-four-hour blood plasma nicotine and cotinine concentrations and 48-hour self-reported nicotine withdrawal symptoms and rewarding effects. Findings Analyses used analysis of variance (ANOVA)-based mixed models with order of product (e-cigarette or cigarette) and product type (combustible cigarette or type of e-cigarette) as fixed effects, and subject as a repeated effect. During a 24-hour period, e-cigarettes produced lower nicotine exposure than cigarettes for the majority of users, although 25% received more nicotine from e-cigarettes, which was predicted by more frequent e-cigarette use or greater dependence. Compared to cigarette smoking, nicotine exposure for variable-power tank users was similar, while cig-a-like (t (30) = 2.71, P = 0.011, d = 0.745) and fixed-power tank users (t (30) = 3.37, P = 0.002, d = 0.993) were exposed to less nicotine. Cigarettes were rated higher than e-cigarettes on some desirable subjective effects (e.g. psychological reward, t (322) = 7.24 P < 0.001, d = 0.432), but withdrawal symptom reduction was comparable. No differences were found between e-cigarette types, but Bayes factors indicate that these measures were insensitive.Conclusions During a 24-hour period in a hospital setting in the United States, nicotine exposure for dual users of ecigarettes and cigarettes was similar when using cigarettes or variable-power tank devices only but was lower for those using cig-a-like or fixed-power devices only. Despite lower nicotine levels, all types of e-cigarette were effective in preventing withdrawal symptoms. E-cigarettes were rated less rewarding than cigarettes.