Sample size and statistical methods
From previous studies, it had been observed that CNicotine concentration data were analysed using SAS. Prior to the calculation of derived pharmacokinetic (PK) parameters, concentration value(s) below the lower limit of quantification (LLOQ) were assigned a value of zero if the timepoint was prior to product use and LLOQ/2 otherwise.The nicotine PK parameters CDerived PK parameters were listed and summarised for each product by gender and overall. Descriptive statistics presented were N (total study population completing each arm), n (PK set for each parameter/arm), arithmetic mean, geometric mean (with the exception of TStatistical comparisons were performed to test the following hypotheses: the addition of different acid ratios to the e-liquid results in different plasma nicotine compared to lactic acid only; higher concentrations of nicotine in the e-liquid increases the level of plasma nicotine compared to lower concentrations; a fixed puffing protocol yields a different plasma nicotine pharmacokinetic profile compared with that of an ad libitum puffing protocol; and the plasma nicotine concentrations for each e-cigarette are not higher than those obtained from a cigarette.For the product liking subjective effects measure, data were listed by participant and summarised by product using descriptive statistics (N, n, mean, SD, minimum, median and maximum).