PT  - JOURNAL ARTICLE
AU  - Randall R. Miller
AU  - George A. Doss
AU  - Ralph A. Stearns
TI  - IDENTIFICATION OF A HYDROXYLAMINE GLUCURONIDE METABOLITE OF AN ORAL HYPOGLYCEMIC AGENT
AID  - 10.1124/dmd.32.2.178
DP  - 2004 Feb 01
TA  - Drug Metabolism and Disposition
PG  - 178--185
VI  - 32
IP  - 2
4099  - http://dmd.aspetjournals.org/content/32/2/178.short
4100  - http://dmd.aspetjournals.org/content/32/2/178.full
SO  - Drug Metab Dispos2004 Feb 01; 32
AB  - Glucuronides of piperazine hydroxylamines are rarely reported in the literature, and even more rarely are their structures unambiguously identified. One major metabolite was detected by liquid chromatography/mass spectrometry-radioactivity in urine from monkeys treated with the aryl piperazine oral hypoglycemic agent 9-[(1S,2R)-2-fluoro-1-methylpropyl]-2-methoxy-6-(1-piperazinyl) purine hydrochloride (1). The mass spectrum of this metabolite indicated that it was both monooxygenated and glucuronidated on the piperazine ring. Possible structures included the N- or O-glucuronic acid conjugates of a carbinolamine, hydroxylamine, or N-oxide. Treatment with β-glucuronidase gave a monooxygenated derivative of the parent compound. 1H NMR analysis of either the glucuronic acid conjugate or the monooxygenated product provided insufficient evidence to unambiguously determine their structures. Incubation of 1 with pig liver microsomes resulted in formation of the same monooxygenated derivative derived from β-glucuronidase treatment of the glucuronide metabolite. This in vitro system was used to generate sufficient material for analysis by 13C NMR, and the metabolite was identified as a hydroxylamine derivative 2. Incubation of the hydroxylamine with monkey liver microsomes and uridine diphospho-5′-glucuronic acid gave the same glucuronic acid conjugate as that observed in monkey urine. 13C NMR analysis of this biosynthetic product led to its unequivocal structure assignment as the O-glucuronic acid conjugate of the hydroxylamine 3. The American Society for Pharmacology and Experimental Therapeutics