title: Highly sensitive method for the determination of 5-fluorouracil in biological samples in the presence of 2'-deoxy-5-fluorouridine by gas chromatography-mass spectrometry.
abstract: A highly sensitive and convenient gas chromatographic-mass spectrometric (GC-MS) method is described for the determination of 5-fluorouracil in the presence of 2'-deoxy-5-fluorouridine (which breaks down into 5-fluorouracil during ordinary GC derivatization) in biological samples such as plasma and urine. After extraction with ethyl acetate, 5-fluorouracil and 5-chlorouracil, the latter being used as an internal standard, were converted into their tert.-butyldimethylsilyl derivatives by allowing the mixture to stand for 30 min at room temperature and were assayed by electron-impact ionization GC-MS. Under these conditions, 2'-deoxy-5-fluorouridine did not decompose or interfere with the determination of 5-fluorouracil. The assay method, including the extraction and tert.-butyldimethylsilyl derivatization of 5-fluorouracil, showed good linearity in the range 0-100 ng/ml for 5-fluorouracil in plasma (detection limit 0.5 ng/ml) and urine (detection limit 1 ng/ml). The usefulness of this method was demonstrated by determining plasma concentrations of 5-fluorouracil in rats treated intravenously with 5-fluorouracil and 2'-deoxy-5-fluorouridine.
authors.affiliation: Department of Drug Metabolism and Analytical Research, Tokushima Research Institute, Otsuka Pharmaceutical Co., Ltd, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kubo
authors.forename: H
authors.initials: H
authors.lastname: Sasabe
authors.forename: T
authors.initials: T
authors.lastname: Shimizu
mesh_terms: D000081:Acetamides; D000818:Animals; D005467:Floxuridine; D005463:Fluoroacetates; D005472:Fluorouracil / Q000097:blood* / Q000493:pharmacokinetics / Q000652:urine; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods* / Q000706:statistics & numerical data; D007202:Indicators and Reagents; D008297:Male; D017646:Organosilicon Compounds; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000081:Acetamides; D005463:Fluoroacetates; D007202:Indicators and Reagents; D017646:Organosilicon Compounds; D005467:Floxuridine; C059151:N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide; D005472:Fluorouracil