title: A sensitive assay of 5-fluorouracil in plasma by gas chromatography-mass spectrometry.
abstract: 1 A gas chromatographic-mass spectrometric method was developed for determining 5-fluorouracil in plasma, using methylated thymine as an internal standard. 2 5-fluorouracil was extracted from plasma by a novel procedure which removed plasma components interferring with the sensitivity of the assay. The method included heating the plasma, washing with ether and extracting the drug under optimum conditions. 3 The sensitivity of the assay was 10 ng/ml plasma, sufficient to determine the low concentrations of 5-fluorouracil found in plasma during continuous infusion of the drug in patients receiving chemotherapy for cancer.
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D005472:Fluorouracil / Q000097:blood* / Q000627:therapeutic use; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D009369:Neoplasms / Q000188:drug therapy
chemical_list: D005472:Fluorouracil