Site of nicotine absorption from a vapour inhaler - comparison with cigarette smoking

Objective: The aim of the study was to assess the site of nicotine absorpti on during and after use of a nicotine-vapour inhaler compared with that aft er cigarette smoking. Methods: Using a catheterisation technique, the nicotine plasma concentrati on-time profiles in arterial and jugular venous blood after using a nicotin e inhaler were compared with those achieved after cigarette smoking a in se ven healthy habitual smokers. Results: After use of the inhaler, arterial nicotine concentrations rose sl owly to a maximum level of 5.9 +/- 1.5 ng/ml at a mean time to reach peak c oncentration (t(max)) of 9.0 +/- 1.1 min, whereas jugular venous nicotine l evels peaked at 25.4 +/- 5.4 ng/ml at 6.7 +/- 0.3 min. The concentration-ti me curves indicate that the absorption occurs mainly via the mucosa of the oral cavity and the pharynx, and that there is minimal absorption via the l ungs. In contrast, after smoking a cigarette, arterial nicotine plasma conc entrations rose quickly to a maximum level of 49.2 +/- 9.7 ng/ml after 4.0 +/- 0.6 min, while the maximum concentration of nicotine in the jugular vei n was 22.4 +/- 3.9 ng/ml after 6.4 +/- 0.4 min, indicating primarily pulmon ary absorption of nicotine. Conclusion: Nicotine absorption after use of the vapour inhaler occurs prim arily via the mucosa of the oral cavity; the absorption occurs slowly and t he arterial nicotine concentration spike, typical of cigarette smoking, is avoided. Thus, the Likelihood for abuse of the nicotine inhaler is probably small.