Effects of User Puff Topography, Device Voltage, and Liquid Nicotine Concentration on Electronic Cigarette Nicotine Yield: Measurements and Model Predictions

Abstract

Introduction: Some electronic cigarette (ECIG) users attain tobacco cigarette-like plasma nicotine concentrations while others do not. Understanding the factors that influence ECIG aerosol nicotine delivery is relevant to regulation, including product labeling and abuse liability. These factors may include user puff topography, ECIG liquid composition, and ECIG design features. This study addresses how these factors can influence ECIG nicotine yield. Methods: Aerosols were machine generated with 1 type of ECIG cartridge (V4L CoolCart) using 5 distinct puff profiles representing a tobacco cigarette smoker (2-s puff duration, 33-ml/s puff velocity), a slow average ECIG user (4 s, 17 ml/s), a fast average user (4 s, 33 ml/s), a slow extreme user (8 s, 17 ml/s), and a fast extreme user (8 s, 33 ml/s). Output voltage (3.3-5.2 V or 3.0-7.5 W) and e-liquid nicotine concentration (18-36 mg/ml labeled concentration) were varied. A theoretical model was also developed to simulate the ECIG aerosol production process and to provide insight into the empirical observations. Results: Nicotine yields from 15 puffs varied by more than 50-fold across conditions. Experienced ECIG user profiles (longer puffs) resulted in higher nicotine yields relative to the tobacco smoker (shorter puffs). Puff velocity had no effect on nicotine yield. Higher nicotine concentration and higher voltages resulted in higher nicotine yields. These results were predicted well by the theoretical model (R 2 = 0.99). Conclusions: Depending on puff conditions and product features, 15 puffs from an ECIG can provide far less or far more nicotine than a single tobacco cigarette. ECIG emissions can be predicted using physical principles, with knowledge of puff topography and a few ECIG device design parameters.

Electronic Cigarette Effectiveness and Abuse Liability: Predicting and Regulating Nicotine Flux

“…For example, a high-voltage/low nicotine concentration combination can give the same or greater flux as a low-voltage/high nicotine concentration combination. 3 The flux, in turn, determines the effect of a given nicotine dose, ranging from no effect to acute toxicity. If ECIG nicotine flux is low, users likely will abandon the device as they would a passenger vehicle that has a top speed of 3 km/hr.…”

“…3 For example, nicotine flux increases with longer puff duration and greater voltage and is unaffected by puff velocity. 3 The effect of product characteristics on nicotine flux can be represented by a "design efficacy index" (Z d ). Similarly, the ways that puff topography can influence nicotine flux can be represented by a puffing intensity parameter (Z p ).…”

“…Studies examining a small subset of these configurations indicate that, in a 5-min use session, an ECIG can produce aerosol with nicotine yields ranging from near zero to many times that of a single combustible tobacco cigarette. [2][3][4] Consumer control over so many characteristics of a nicotine delivery device is a marked departure from the combustible tobacco cigarette that, by comparison, constrains the range of product choices, with a comparatively limited range of nicotine yields. ECIGs thus present a regulatory challenge, particularly with regard to one central issue: nicotine delivery to the user.…”

“…To control nicotine delivery effectively, regulations will need to account for product design, element features, liquid composition, and user behavior in combination, rather than separately. 3 In this commentary, we propose a conceptual framework intended to provide a convenient approach for evaluating from a drug administration perspective the multiplicity of possible ECIG/user behavior configurations. This framework centers on the concept of nicotine flux ( m nic ), which is the rate at which nicotine flows from the mouth end of the ECIG per puff second (e.g., mg/s).…”

Risks of Attempting to Regulate Nicotine Flux in Electronic Cigarettes

“…Surveys of dedicated EC users (which were all former smokers) have shown that high nicotine levels are important especially for the initiation of EC use. 3,4 Although nicotine delivery to the aerosol can be similar or higher than tobacco cigarettes, 5,6 clinical studies of EC use have shown that the nicotine absorption potential is significantly lower compared with tobacco cigarettes, even when new generation devices are used. 7 This is mostly attributed to the low speed of nicotine absorption, and clearly indicates that nicotine intoxication is highly unlikely when ECs are used as intended.…”