TY - JOUR T1 - Stereospecific in vivo N-methylation of nicotine in the guinea pig. JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 175 LP - 185 VL - 13 IS - 2 AU - K C Cundy AU - M Sato AU - P A Crooks Y1 - 1985/03/01 UR - http://dmd.aspetjournals.org/content/13/2/175.abstract N2 - R-(+)-[3H-N'-CH3]N-methylnicotinium ion has been identified as a urinary metabolite of ip administered R-(+)-[3H-N'-CH3]nicotine in the guinea pig. Under similar conditions, S-(-)-[3H-N'-CH3]nicotine is not converted to the corresponding N-methylated metabolite. R-(+)-N-methylnicotinium salt was isolated from the urine of guinea pigs that had been chronically dosed ip with R-(+)-nicotine. The identification and stereochemical analysis of this metabolite were carried out using analytical and preparative cation exchange high pressure liquid chromatography and chemical reduction followed by GLC-mass spectrometric analysis and 1H NMR spectroscopy. The results show that nicotine is stereospecifically biotransformed into an N-methylated urinary metabolite in the guinea pig. ER -