Discussion
AUCAs, NRS
We evaluated PK parameters of four flavor variants of e-liquids used in Vuse Solo ENDS which include 4.8% nicotine by weight (~ 57 mg/mL), and contain nicotine salts following an acute exposure in predominately ENDS naïve smokers. Our data showed that subjects achieved similar overall nicotine exposure (AUCAs stated above, the results and distribution of baseline adjusted CAs was the case with CSt. Helen and colleagues examined the impact of flavors (Strawberry vs. Tobacco) on nicotine uptake and topographyIn addition to PK assessments, subjects were also asked to rate OPL for the Vuse Solo flavor variants on an 11-point NRS at 13 min after initiating the ENDS use. Subjects rated the Tropical flavor highest, followed by the Original (tobacco), Fusion, and Mint flavor (Table Similarly, in a topography study to assess the effect of flavor in regular smokers, Voos et al. concluded that the flavors used in their study delivered differential amounts of nicotine, potentially associated with product use topography, and that differences in subjective effects are not solely a product of nicotine delivery and recommended additional researchIn this study, subjects were asked to familiarize themselves with ENDS products at home for one week prior to a PK test session. For at-home trial use, subjects were dispensed two cartridges of ENDS product flavor they were randomized to use during a PK test session with an option to request more had they used both prior to the end of the at-home trial period. Subjects were encouraged to use ENDS at least once a day while they continue to use their usual brand of cigarettes. All subjects returned one partially used cartridge at check-in, along with their second cartridge which no subject had begun to use. The amount of e-liquid consumed was measured by differences in cartridges weights obtained before and after a week of at home use, where ENDS naïve subjects were encouraged to use the ENDS ad libitum as often as possible. We found that subjects used approximately 10% of e-liquid by weight ranging from 0.16 (± 0.17) mg to 0.21 (± 0.25) mg across the four flavors (Table Subjects were also required to abstain from tobacco products for 12 h prior to PK test sessions to ensure their blood nicotine concentrations were close to baseline prior to the start of product use. Furthermore, we collected blood samples at intervals that allowed characterization of nicotine PK following ad libitum ENDS exposure and the nicotine concentrations of blood samples were baseline-adjusted to ensure more accurate results. Lastly, for this study, subjects were allowed a 10-min ad libitum use of the ENDSThis study had several limitations. Although we allowed participation of dual users, more than 90% of our subjects were exclusive cigarette smokersIn conclusion, the primary endpoints of this study, C