Electronic cigarette nicotine delivery can exceed that of combustible cigarettes: a preliminary report.
BACKGROUND
Electronic cigarettes (ECIGs) aerosolise a liquid that usually contains propylene glycol and/or vegetable glycerine, flavourants and the dependence-producing drug, nicotine, in various concentrations. This laboratory study examined the relationship between liquid nicotine concentration and plasma nicotine concentration and puffing behaviour in experienced ECIG users.


METHODS
Sixteen ECIG-experienced participants used a 3.3-Volt ECIG battery attached to a 1.5-Ohm dual-coil 'cartomiser' loaded with 1 mL of a flavoured propylene glycol/vegetable glycerine liquid to complete four sessions, at least 2 days apart, that differed by nicotine concentration (0, 8, 18 or 36 mg/mL). In each session, participants completed two 10-puff ECIG-use bouts (30 s puff interval) separated by 60 min. Venous blood was sampled to determine plasma nicotine concentration. Puff duration, volume and average flow rate were measured.


RESULTS
Immediately after bout 1, mean plasma nicotine concentration was 5.5 ng/mL (SD=7.7) for 0 mg/mL liquid, with significantly (p<0.05) higher mean concentrations observed for the 8 (mean=17.8 ng/mL, SD=14.6), 18 (mean=25.9 ng/mL, SD=17.5) and 36 mg/mL (mean=30.2 ng/mL; SD=20.0) concentrations; a similar pattern was observed for bout 2. For bout 1, at 36 mg/mL, the mean post- minus pre-bout difference was 24.1 ng/mL (SD=18.3). Puff topography data were consistent with previous results and revealed few reliable differences across conditions.


CONCLUSIONS
This study demonstrates a relationship between ECIG liquid nicotine concentration and user plasma nicotine concentration in experienced ECIG users. Nicotine delivery from some ECIGs may exceed that of a combustible cigarette. The rationale for this higher level of nicotine delivery is uncertain.
Center for the Study of Tobacco Products, Virginia Commonwealth University, Richmond, Virginia, USA Department of Psychology, Virginia Commonwealth University, Richmond, Virginia, USA.
Carolina P
CP
Ramôa
Center for the Study of Tobacco Products, Virginia Commonwealth University, Richmond, Virginia, USA Department of Psychology, Virginia Commonwealth University, Richmond, Virginia, USA.
Marzena M
MM
Hiler
Center for the Study of Tobacco Products, Virginia Commonwealth University, Richmond, Virginia, USA Department of Psychology, Virginia Commonwealth University, Richmond, Virginia, USA.
Tory R
TR
Spindle
Center for the Study of Tobacco Products, Virginia Commonwealth University, Richmond, Virginia, USA Department of Psychology, Virginia Commonwealth University, Richmond, Virginia, USA.
Alexa A
AA
Lopez
Department of Mechanical Engineering, American University of Beirut, Beirut, Lebanon.
Nareg
N
Karaoghlanian
Center for the Study of Tobacco Products, Virginia Commonwealth University, Richmond, Virginia, USA Department of Internal Medicine, Virginia Commonwealth University, Richmond, Virginia, USA.
Thokozeni
T
Lipato
Center for the Study of Tobacco Products, Virginia Commonwealth University, Richmond, Virginia, USA Department of Psychology, Virginia Commonwealth University, Richmond, Virginia, USA.
Alison B
AB
Breland
Center for the Study of Tobacco Products, Virginia Commonwealth University, Richmond, Virginia, USA Department of Mechanical Engineering, American University of Beirut, Beirut, Lebanon.
Alan
A
Shihadeh
Center for the Study of Tobacco Products, Virginia Commonwealth University, Richmond, Virginia, USA Department of Psychology, Virginia Commonwealth University, Richmond, Virginia, USA.
Thomas
T
Eissenberg
D000280:Administration, Inhalation; D000328:Adult; D000336:Aerosols; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D066300:Electronic Nicotine Delivery Systems; D005260:Female; D006801:Humans; D008297:Male; D009538:Nicotine / Q000008:administration & dosage* / Q000097:blood; D018722:Nicotinic Agonists / Q000008:administration & dosage* / Q000097:blood; D012907:Smoking / Q000009:adverse effects; D016540:Smoking Cessation / Q000379:methods*; D000074606:Smoking Prevention; D013997:Time Factors; D062789:Tobacco Products / Q000032:analysis*; D014029:Tobacco Use Disorder / Q000628:therapy*; D000072137:Vaping; D055815:Young Adult
D000336:Aerosols; D018722:Nicotinic Agonists; D009538:Nicotine
Addiction; Electronic nicotine delivery devices; Nicotine