Plasma Determinations of Nicotine and Cotinine: Biological Markers of Tobacco

Abstract

We have effected basal determinations of nicotine (N) and cotinine (C) in plasma of 33 smokers (N: 12.12 .+ 3.1; C: 34.79 +_ 14.97 ngiml). After an acute tobacco atimulus in the form of smoking 2 cigarettes with 1.1 mg of nicotine each, the concentrations of nicotine rose inmediately (33.78 + 6.53 ngiml; p < O.OOOl), decreasing ten minutes later (24.86 + 5.35 ng/ml), although still high when compared to basal levels (p < 0.0001). Cotinine not only increased after smoking (214.67 + 39.66 ngiml; p < O.OOOl), but also continued increasing after ten minutes (320.44 + 43.88 ng/ml; p < 0.0001). Our results establish the efficacy of nicotine and cotinine determinations as biological markers of exposure, recent and chronic respectively, to tobacco smoke, suitable for use in epidemiological studies, as well as the suitability of the tobacco overidad model produced, with a view to later research into the acute effects of tobacco on different organic systems.