title: Rapid determination of gemcitabine in plasma and serum using reversed-phase HPLC.
abstract: Gemcitabine (2'2'-difluorodeoxycytidine) is a pyrimidine analog used in the treatment of a variety of solid tumors. After intravenous (i.v.) administration, it is rapidly inactivated to 2'-deoxy-2',2'-difluorouridine (dFdU). A sensitive analytical method for the quantitation of gemcitabine is required for the assessment of alternative dosage and treatment schemes. A rapid and robust RP-HPLC assay for analysis of gemcitabine in human and animal plasma and serum was developed and validated using 2'-deoxyuridine (dU) and 5-fluoro-2'-deoxyuridine (5FdU) as internal standards. It is based on protein precipitation, the use of an Atlantis dC18 column of 100 mm length (inner diameter, 4.6 mm; particle size, 3 microm) and isocratic elution using a 10 mM phosphate buffer, pH 3.0, followed by isocratic elution with the same buffer containing 3% of ACN. For gemcitabine, RSD values for intraday and interday precision were < 4.4 and 5.3%, respectively, the LOQ was 20 ng/mL, and the assay was linear in the range of 0.020-20 microg/mL with an accuracy of > or =89%. The recovery for gemcitabine, dU and 5FdU was 86-98%. The assay was applied to determine gemcitabine levels in plasma samples of patients collected during and shortly after conventional infusion of 25-30 mg/kg body mass (levels: 2.0-18.9 microg/mL) and rats that received lower doses (1.5 mg/kg) via i.v., subcutaneous and oral drug administration (levels: 0.20-2.60 microg/mL). It could also be applied to estimate dFdU levels in human plasma.
authors.affiliation: Departement für Innere Medizin, Fachbereich Onkologie/Hämatologie, Kantonsspital St. Gallen, Switzerland. christian.lanz@ikp.unibe.ch
authors.forename: Christian
authors.initials: C
authors.lastname: Lanz
authors.forename: Martin
authors.initials: M
authors.lastname: Früh
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Thormann
authors.forename: Thomas
authors.initials: T
authors.lastname: Cerny
authors.forename: Bernhard H
authors.initials: BH
authors.lastname: Lauterburg
mesh_terms: D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage / Q000032:analysis* / Q000097:blood*; D001774:Blood Chemical Analysis / Q000379:methods*; D002138:Calibration; D002624:Chemistry, Clinical / Q000379:methods; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood; D005467:Floxuridine / Q000097:blood; D006801:Humans; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D044967:Serum / Q000378:metabolism*; D000093542:Gemcitabine
chemical_list: D000964:Antimetabolites, Antineoplastic; D005467:Floxuridine; D003841:Deoxycytidine; D000093542:Gemcitabine