Assay of the Acetyl-CoA Probe Acetyl-Sulfamethoxazole and of Sulfamethoxazole by Gas Chromatography-Mass Spectrometry

• Published in: Analytical biochemistry Vol. 212; no. 2; pp. 481 - 486
• Main Authors: Ying, Z., Agarwal, K.C., Beylot, M., Soloviev, M.V., David, F., Reider, M., Tserng, K.Y., Brunengraber, H.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.08.1993; Elsevier
• Subjects: Acetyl Coenzyme A - analysis; Analysis; Animals; Biological and medical sciences; Deuterium; Fluorobenzenes; Gas Chromatography-Mass Spectrometry - methods; General pharmacology; Humans; Male; Medical sciences; Middle Aged; Pharmacology. Drug treatments; Rats; Rats, Sprague-Dawley; Reference Standards; Sulfamethoxazole - analogs & derivatives; Sulfamethoxazole - analysis; Sulfamethoxazole - blood; Sulfamethoxazole - urine; Human; Urine; Rat; Metabolite; Rodentia; Isotope dilution; Blood plasma; Assay; Gas chromatography; Antibiotic; Vertebrata; Mammalia; Analysis method; Acetyl coenzyme A; Pharmacokinetics; Mass spectrometry
• ISSN: 0003-2697; 1096-0309
• DOI: 10.1006/abio.1993.1357

We present gas chromatographic-mass spectrometric assays for (i) the concentration of sulfamethoxazole and (ii) the concentration and molar percentage enrichment of acetyl-sulfamethoxazole in biological fluids. The compounds are extracted with ethyl acetate, derivatized with either diazomethane or pentafluorobenzyl bromide, and analyzed by gas chromatography-mass spectrometry. Quantitation is achieved using internal standards, [ 2H 4]sulfamethoxazole and acetyl-[ 2H 4]sulfamethoxazole. Limits of detection are 200 nmol for the methyl derivatives and 2 nmol for the pentafluorobenzyl derivatives. The high sensitivity of the assay with the pentafluorobenzyl derivatives allows measuring in plasma and urine (i) the pharmacokinetics of sulfamethoxazole and acetyl-sulfamethoxazole and (ii) the stable isotope enrichment of the acetyl moiety of acetyl-sulfamethoxazole. The latter is used as a probe for the noninvasive chemical biopsy of liver extramitochondrial acetyl-CoA.