title: Measurement of the anti-cancer agent gemcitabine in human plasma by high-performance liquid chromatography.
abstract: A reversed-phase HPLC assay has been developed to determine the concentration of the anti-metabolite 2',2'-difluorodeoxycytidine (gemcitabine, dFdC) in human plasma over the concentration range of 0.5-150 microM (0.13-39.44 microg/ml), and 2',2'-difluorodeoxyuridine (dFdU), the deaminated, inactive metabolite, over the range of 1.0-227 microM (0.26-60 microg/ml). After the addition of 20 nmol 2'-fluorodeoxycytidine (FdC) as an internal standard, 0.5-ml samples of plasma were subjected to acetonitrile precipitation, followed by analysis using a gradient reversed-phase HPLC assay with UV detection. A Phenomenex Columbus C(18) column, 5 microm, 150 x 4.6 mm, and a Waters C(18), 4 microm, Nova-Pak Sentry guard column were used to achieve separation. FdC, dFdC and dFdU were monitored at 282, 269 and 258 nm, respectively, on a Waters 996 photodiode array detector. The mobile phase, run at a total flow-rate of 1.5 ml/min, was composed of two solvents: 50 mM ammonium acetate pH 5.0 in either 2% (solvent A) or 10% methanol (solvent B, v/v); 100% solvent A was run for 17 min, followed by a linear gradient to 100% solvent B over 14 min. FdC, dFdC and dFdU were resolved from endogenous compounds and had retention times of 13.6+/-0.5, 18.1+/-1.1 and 29.0+/-0.6 min, respectively. The assay was useful in measuring the plasma levels of both analytes in samples obtained from adult cancer patients participating in a Phase I trial of gemcitabine given as either a 1- or 2-h infusion weekly for 3 of 4 weeks.
authors.affiliation: Cancer Therapeutics Branch, Center for Cancer Research, National Cancer Institute at the National Naval Medical Center, Building 8, Room 5101, 8901 Wisconsin Ave., Bethesda, MD 20889-5105, USA.
authors.forename: Bruce
authors.initials: B
authors.lastname: Keith
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.forename: Jean L
authors.initials: JL
authors.lastname: Grem
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000097:blood*; D006801:Humans; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D000093542:Gemcitabine
chemical_list: D000964:Antimetabolites, Antineoplastic; D003841:Deoxycytidine; D000093542:Gemcitabine