The metabolism of nicotine into two optically-active stereoisomers of nicotine-1′-oxide by animal tissues in vitro and by cigarette smokers

Nicotine-1′-oxide, prepared by the oxidation of (−)-nicotine with hydrogen peroxide, has been resolved into two optically active stereoisomers by fractional precipitation with ammonium reineckate. (−)-Nicotine is enzymically oxidized into both isomers of nicotine-1′-oxide in vitro. These enzyme systems are stereospecific since guinea-pig and rabbit liver form similar amounts of each stereoisomer white BALB/c mouse and hamster liver and guinea-pig lung synthesize chiefly laevo-rotatory nicotine-1′-oxide. Both stereoisomers of nicotine-1′-oxide were identified in the urine of cigarette smokers.