Cotinine trans-3 -hydroxycotinine

Dobrinas M, Choong E, NoetzU M, Comuz J, Ansermot N, Eap CB. Quantification of nicotine, cotinine, trans-3 -hydroxycotinine and varenicline in human plasma by a sensitive and specific UPLC—tandem mass-spectrometry procedure for a clinical study on smoking cessation. J Chromatogr B Anal Tech Biomed Life Sci 2011 879 3574-82. 

Quantitative aspects of the pattern of nicotine metabolism have been elucidated fairly well in people (Fig. 4). Approximately 90% of a systemic dose of nicotine can be accounted for as nicotine and metabolites in urine (Benowitz et al. 1994). Based on studies with simultaneous infusion of labeled nicotine and cotinine, it has been determined that 70-80% of nicotine is converted to cotinine (Benowitz and Jacob 1994). About 4-7% of nicotine is excreted as nicotine N -oxide and 3-5% as nicotine glucuronide (Benowitz et al. 1994 Byrd et al. 1992). Cotinine is excreted unchanged in urine to a small degree (10-15% of the nicotine and metabolites in urine). The remainder is converted to metabolites, primarily fra i -3 -hydroxycotinine (33 0%), cotinine glucuronide (12-17%), and trans-3 -hydroxycotinine glucuronide (7-9%). 

Byrd GD, Chang KM, Greene JM, deBethizy JD (1992) Evidence for urinary excretion of glu-curonide conjugates of nicotine, cotinine, and trans-3 -hydroxycotinine in smokers. Drug Metab Dispos 20(2) 192-197... 

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