What is the nicotine delivery profile of electronic cigarettes?

Abstract

Introduction: Electronic cigarettes (e-cigarettes) are a rapidly evolving class of tobacco products intended to deliver nicotine to users. There are many types of e-cigarettes available and the most popular type today in the United States are 'pod' based devices that use high nicotine concentration liquids. Understanding the nicotine delivery capabilities of e-cigarettes is imperative for understanding their addictive potential and safety profile, informing regulation, and revealing their potential use as smoking cessation aids. Areas covered: This review discusses nicotine content of e-cigarettes, effectiveness of nicotine aerosolization by devices, delivery of nicotine to users, and user and device characteristics that impact each of these. Expert opinion: Modern e-cigarettes have the potential to deliver equal or more nicotine compared to a tobacco cigarette. Future research needs to identify the nicotine delivery profiles likely to benefit public health and the means to regulate them appropriately while also identifying those that are likely to cause harm. Public health benefit accrues if e-cigarettes help smokers quit combustible cigarettes completely. Harm is possible if inadequate nicotine delivery undermines cessation attempts, e-cigarettes facilitate continued combustible cigarette use, long-term e-cigarette use is associated with substantial morbidity/mortality, and/or e-cigarettes increase the initiation of combustible cigarette use among never smokers.

Keywords: addiction; dependence; e-cigarettes; nicotine; tobacco control.

Figure 1.

E-Cigarette Generations. (A) First generation devices (“cig-a-likes”). (B) Second generation devices. (C) Third generation devices (“mods”). (D) Pod-based systems (on the left is the JUUL, and on the right is the Sourin Drop)

Figure 2.. Variability in e-cigarette nicotine delivery (adapted from Breland et al. [3]).

Mean (SEM) plasma nicotine concentration from different human laboratory studies and different products with blood sampled before and immediately after a 10-puff product use bout. Combustible cigarette data from [59]. ECIG A is a first generation device [61]. ECIG B is a first generation device, and ECIG C is a third generation device [63]. ECIG D is a second generation device [70,71]. Data for ECIG Type E are from a group of second generation devices (mean power output = ~8 W), and data for ECIG Type F are from a group of third generation devices (mean power output = ~71 W) [35]; note that the higher-powered ECIG Type F delivers more nicotine to the user despite being paired with a lower concentration nicotine liquid (i.e., ~4 mg/ml) [69]. Figure adapted from Breland et al., 2017 [3]. Copyright 2016 New York Academy of Sciences.