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TSRC, Tob. Sci. Res. Conf., 2023, 76, abstr. 31

An abuse liability comparison of test and reference tobacco and menthol flavored e-liquids in the RELX Infinity electronic nicotine delivery system (ENDS)

(1) Cheerain HK Limited, Hong Kong, China; (2) LA Clinical Trials, Burbank, CA, USA; (3) Safety in Numbers, Tucson, AZ, USA

Reference and test tobacco and menthol flavored e-liquids (4% nicotine) used with the RELX Infinity ENDS (a closed 2 mL pod with a ceramic/metal coil atomizer) were evaluated in a randomized, two-arm, cross-over study of adult closed-system ENDS users to determine whether within-category flavor differences may raise unique concerns for abuse liability.

Subjects were assigned to a study arm (tobacco or menthol, n = 20 per arm) based on their preferred usual flavor and randomized to the order they received reference and test e-liquids. Each product was used at home for 14 days during which subjects documented use daily. Subjects returned to the clinic for additional study activities, including a 5-minute ad libitum product use and 30 minutes of blood sampling for nicotine concentration measurement, product use measurements (puffing topography and pod weight change), subjective measures assessments, and safety and tolerability reporting.

No statistically significant or clinically meaningful differences in the number of pods used per day during the 14-day ambulatory periods were observed between test and reference formulations for either e-liquid flavor. In addition, the amount of e-liquid consumed per day during the ambulatory periods and clinic sessions was comparable between formulations for both e-liquid flavors. Furthermore, a 5-minute use of the test and reference tobacco and menthol flavored products resulted in comparable levels of nicotine uptake (Cmax and AUC0-30) and a similar time to reach the maximum concentration (Tmax). There were no remarkable differences between the test and reference formulations for either e-liquid flavor for the subjective or safety measures assessed.

These data suggest that the prototype and test formulations of each flavor are unlikely to exhibit unique concerns for abuse liability compared to the prototype formulations.