Electronic cigarettes (ECIGs) are among the most important issues in public health today due to their dramatic increase in popularity. However, very little is known about ECIGs, including what factors may make them more likely to be used and abused. Examining factors that influence nicotine yield, delivery, and subjective effects from ECIGs is essential to understanding their abuse liability. Limited pre-clinical research has revealed that nicotine yield may be influenced by the ratio of the two liquid vehicles, propylene glycol (PG) and vegetable glycerin (VG), most commonly found in ECIG solutions. Specifically, higher proportions of PG result in greater nicotine yields. However, the aerosols generated in this research were not produced by actual ECIG users' puffing behaviors, suggesting that the nicotine yields found may not be indicative of actual ECIG users' nicotine exposure. Moreover, the influence of PG:VG ratio on nicotine delivery and subjective effects associated with ECIG use has not been examined previously. This proposal describes a two-part study. The first examines the effect of PG and VG on nicotine delivery and subjective effects using a within-subjects design. Thirty experienced ECIG users will use an ECIG in five conditions that will differ only by the PG:VG ratio: 100:0, 70:30, 50:50, 30:70, and 0:100 (device voltage, heater resistance, liquid nicotine concentration, puff number, and interpuff interval all will be held constant). Plasma nicotine concentration, subjective effects, and puffing behaviors will be recorded in each condition. The second will generate ECIG aerosols using the puffing behavior recorded from ECIG users in the first part of the study and under identical experimental conditions (e.g., PG:VG ratio). The aerosol produced will be captured and assessed for nicotine yield. The primary hypotheses are that higher proportions of PG will result in greater nicotine delivery and subjective effect profiles suggestive of higher abuse liability in ECIG users and produce aerosols with higher nicotine yields. Results from this project will result in further understanding of the factors that influence the abuse liability of ECIGs and could inform regulation of these products.

Public Health Relevance

Despite the prevalence of tobacco cigarette smoking being lower than at any other point in the last 20 years, tobacco-related morbidity and mortality is stil alarmingly high. Also of concern is the rapid proliferation of unregulated novel tobacco products such as electronic cigarettes in the U.S. market. This project will address this emerging public health issue by providing information regarding electronic cigarette abuse liability that will be vital for the regulation of these products.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
5F31DA040319-02
Application #
9128408
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Walton, Kevin
Project Start
2015-08-10
Project End
2018-08-09
Budget Start
2016-08-10
Budget End
2017-08-09
Support Year
2
Fiscal Year
2016
Total Cost
Indirect Cost
Name
Virginia Commonwealth University
Department
Psychology
Type
Graduate Schools
DUNS #
105300446
City
Richmond
State
VA
Country
United States
Zip Code
23298
Spindle, Tory R; Talih, Soha; Hiler, Marzena M et al. (2018) Effects of electronic cigarette liquid solvents propylene glycol and vegetable glycerin on user nicotine delivery, heart rate, subjective effects, and puff topography. Drug Alcohol Depend 188:193-199
Spindle, Tory R; Hiler, Marzena M; Cooke, Megan E et al. (2017) Electronic cigarette use and uptake of cigarette smoking: A longitudinal examination of U.S. college students. Addict Behav 67:66-72
Soule, Eric K; Maloney, Sarah F; Spindle, Tory R et al. (2017) Electronic cigarette use and indoor air quality in a natural setting. Tob Control 26:109-112
Spindle, Tory R; Hiler, Marzena M; Breland, Alison B et al. (2017) The Influence of a Mouthpiece-Based Topography Measurement Device on Electronic Cigarette User's Plasma Nicotine Concentration, Heart Rate, and Subjective Effects Under Directed and Ad Libitum Use Conditions. Nicotine Tob Res 19:469-476
Ramôa, Carolina P; Hiler, Marzena M; Spindle, Tory R et al. (2016) Electronic cigarette nicotine delivery can exceed that of combustible cigarettes: a preliminary report. Tob Control 25:e6-9