PT  - JOURNAL ARTICLE
AU  - Omar Ghosheh
AU  - Sarvesh C. Vashishtha
AU  - Edward M. Hawes
TI  - Formation of the Quaternary Ammonium-Linked Glucuronide of Nicotine in Human Liver Microsomes: Identification and Stereoselectivity in the Kinetics
DP  - 2001 Dec 01
TA  - Drug Metabolism and Disposition
PG  - 1525--1528
VI  - 29
IP  - 12
4099  - http://dmd.aspetjournals.org/content/29/12/1525.short
4100  - http://dmd.aspetjournals.org/content/29/12/1525.full
SO  - Drug Metab Dispos2001 Dec 01; 29
AB  - The formation of the N1-glucuronide metabolite of each nicotine enantiomer was studied in pooled human liver microsomes (n = 6). The metabolite formed from natural S(−)-nicotine was identified by comparison of the high-pressure liquid chromatography (HPLC) retention time and positive ion electrospray ionization-mass spectral characteristics with a synthetic reference standard. A radiometric HPLC method was used to quantify the metabolite. The specificity of the assay method was demonstrated by experiments in which β-glucuronidase treatment of incubated assay samples resulted in elimination of the peak due to theN1-glucuronide metabolite. The glucuronides ofS(−)- and R(+)-nicotine were formed by one-enzyme kinetics, with Km values of 0.11 and 0.23 mM and Vmax values of 132 and 70 pmol/min/mg of protein, respectively. There is marked stereoselectivity in the apparent intrinsic clearance values (Vmax/Km) in that the value for S(−)-nicotine is 4 times greater than for the R(+)-isomer (1.2 versus 0.31 μl/min/mg of protein). The American Society for Pharmacology and Experimental Therapeutics