Impact of e-liquid flavors on nicotine intake and pharmacology of e-cigarettes

Gideon St Helen; Delia A Dempsey; Christopher M Havel; Peyton Jacob 3rd; Neal L Benowitz

doi:10.1016/j.drugalcdep.2017.05.042

Impact of e-liquid flavors on nicotine intake and pharmacology of e-cigarettes

Drug Alcohol Depend. 2017 Sep 1:178:391-398. doi: 10.1016/j.drugalcdep.2017.05.042. Epub 2017 Jun 30.

Authors

Gideon St Helen¹, Delia A Dempsey², Christopher M Havel², Peyton Jacob 3rd³, Neal L Benowitz⁴

Affiliations

¹ Division of Clinical Pharmacology and Experimental Therapeutics, Department of Medicine, University of California, San Francisco, CA, USA; Center for Tobacco Control Research and Education, University of California, San Francisco, CA, USA; Tobacco Center of Regulatory Science (TCORS), University of California, San Francisco, CA, USA. Electronic address: Gideon.Sthelen@ucsf.edu.
² Division of Clinical Pharmacology and Experimental Therapeutics, Department of Medicine, University of California, San Francisco, CA, USA.
³ Division of Clinical Pharmacology and Experimental Therapeutics, Department of Medicine, University of California, San Francisco, CA, USA; Center for Tobacco Control Research and Education, University of California, San Francisco, CA, USA; Tobacco Center of Regulatory Science (TCORS), University of California, San Francisco, CA, USA.
⁴ Division of Clinical Pharmacology and Experimental Therapeutics, Department of Medicine, University of California, San Francisco, CA, USA; Center for Tobacco Control Research and Education, University of California, San Francisco, CA, USA; Tobacco Center of Regulatory Science (TCORS), University of California, San Francisco, CA, USA; Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA.

Abstract

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, C_max 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.

Keywords: E-cigarette pharmacology; E-cigarettes; Flavors; Nicotine delivery; Nicotine pharmacokinetics.

MeSH terms

Cross-Over Studies
Electronic Nicotine Delivery Systems*
Flavoring Agents / pharmacology*
Heart Rate / drug effects*
Humans
Nicotine / pharmacology*
Taste / drug effects*
Tobacco Products

Substances

Flavoring Agents
Nicotine

Abstract

MeSH terms

Substances

Grants and funding