Quantitative analysis of 5-fluorouracil and 5,6-dihydrofluorouracil in plasma by gas chromatography mass spectrometry

Abstract

5-Fluorouracil and 5,6-dihydro-5-fluorouracil were analysed in the plasma of patients by combined gas chromatography mass spectrometry. 5-Bromouracil was the internal standard. After extraction from plasma with an isopropanol-diethyl ether mixture (20/80) the components were pentylated and the derivatives produced extracted into diethyl ether. Electron impact mass spectrometry was used for the simultaneous quantitative determinations of 5-fluorouracil and 5,6-dihydro-5-fluorouracil (detection limit 10 ng ml-1 5-fluorouracil, 80 ng ml-1 5,6-dihydro-5-fluorouracil). Chemical ionization was utilized to measure 5,6-dihydro-5-fluorouracil concentrations less than 80 ng ml-1 (sensitivity 10 ng ml-1). The biological applicability of these two techniques was demonstrated by analysing plasma samples from patients after administration of 5-fluorouracil or 5'-deoxyfluorouridine by intravenous injections and infusions.

Passage of 5'-dFUrd and its metabolites 5-FU and 5-FUH2to CSF in a clinical Phase 1 study

“…The methods of analysis were the same as for the analysis in plasma and are described in detail elsewhere (17,18). The methods of analysis were the same as for the analysis in plasma and are described in detail elsewhere (17,18).…”