Quantitation of N-demethylantipyrine in biological samples and isolation and characterization of its glucuronic acid conjugate
Hignite, C.E.; Tschanz, C.; Huffman, D.H.; Azarnoff, D.L.
Drug Metabolism and Disposition the Biological Fate of Chemicals 6(3): 288-295
1978
ISSN/ISBN: 0090-9556 PMID: 26550 Document Number: 130918
An improved method for quantitating N-demethylantipyrine (N-DEM-AP) in urine by gas chromatography or gas chromatography-mass spectrometry has been developed. Recovery of greater than 90% of N-DEM-AP was achieved by extraction of the sample at pH 1 after addition of 3-amino-1-phenyl-2-pyrazolin-5-one. The coefficient of variation of replicate analyses was 8%. N-DEM-AP was excreted in the urine as a glucuronic acid conjugate. This conjugate was isolated from the urine of an individual receiving antipyrine and purified. The NMR and mass-spectral data are consistent with the conjugate being an O-glucuronide of N-DEM-AP in its enol form.