title: Gas chromatography-mass spectrometry identification of a novel N3-methylated metabolite of 5'-deoxy-5-fluorouridine in plasma of cancer patients undergoing chemotherapy.
abstract: Evidence of in vivo biomethylation of the anticancer pro-drug 5'-deoxy-5-fluorouridine (5'-dFUR) is presented for the first time. Biomethylation seems to occur specifically at the N3 site on the pyrimidine ring. This novel metabolic product was detected by gas chromatography-mass spectrometry of the trimethylsilylated extract of plasma samples from cancer patients undergoing doxifluridine chemotherapy. Considering the observed electron impact fragmentation pattern, the metabolic product was tentatively identified as N3-Me-5'-dFUR. Definite confirmation of the proposed structure was achieved by comparison of the mass spectra and chromatographic characteristics of the suspected metabolite with those of a synthetically prepared reference standard.
authors.affiliation: Dipartimento di Chimica, Universitá degli Studi di Bari, Italy.
authors.forename: C G
authors.initials: CG
authors.lastname: Zambonin
authors.forename: F
authors.initials: F
authors.lastname: Palmisano
mesh_terms: D000970:Antineoplastic Agents / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005467:Floxuridine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood* / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D009369:Neoplasms / Q000097:blood / Q000188:drug therapy; D011355:Prodrugs / Q000378:metabolism*; D012015:Reference Standards
chemical_list: D000970:Antineoplastic Agents; C103213:N(3)-methyl-5'-deoxy-5-fluorouridine; D011355:Prodrugs; D005467:Floxuridine; C025034:doxifluridine