title: Assay of the acetyl-CoA probe acetyl-sulfamethoxazole and of sulfamethoxazole by gas chromatography-mass spectrometry.
abstract: 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, [2H4]sulfamethoxazole and acetyl-[2H4]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.
authors.affiliation: Department of Nutrition, Case Western Reserve University, Cleveland, Ohio 44106.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.forename: K C
authors.initials: KC
authors.lastname: Agarwal
authors.forename: M
authors.initials: M
authors.lastname: Beylot
authors.forename: M V
authors.initials: MV
authors.lastname: Soloviev
authors.forename: F
authors.initials: F
authors.lastname: David
authors.forename: M
authors.initials: M
authors.lastname: Reider
authors.forename: K Y
authors.initials: KY
authors.lastname: Tserng
authors.forename: H
authors.initials: H
authors.lastname: Brunengraber
mesh_terms: D000105:Acetyl Coenzyme A / Q000032:analysis*; D000818:Animals; D003903:Deuterium; D005464:Fluorobenzenes; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D051381:Rats; D017207:Rats, Sprague-Dawley; D012015:Reference Standards; D013420:Sulfamethoxazole / Q000031:analogs & derivatives* / Q000032:analysis* / Q000097:blood / Q000652:urine; D005466:Fluorocarbons
chemical_list: D000105:Acetyl Coenzyme A; D003903:Deuterium; D005464:Fluorobenzenes; D013420:Sulfamethoxazole; C025063:pentafluorobenzyl bromide; D005466:Fluorocarbons; C021282:N(4)-acetylsulfamethoxazole