title: Measurement of warfarin in plasma by high performance liquid chromatography (HPLC) and its correlation with the international normalized ratio.
abstract: The measurement of plasma warfarin is required to investigate non-compliance, resistance to anticoagulation, drug metabolism and pharmacokinetic. Methods so far described are based on extraction of warfarin from plasma followed by reversed-phase HPLC. Extraction is the crucial step and may be performed in liquid- or solid-phase. The latter requires the preparation of columns, which makes the procedure variable. We investigated the suitability of the ready-for-use commercial cartridges for sample preparation. The method displayed between-run CV of 11.8%. Recovery was 99%. The coefficients of correlation between warfarin concentration in 50 patients and weekly dosage or INR were 0.55 (p<0.0001) or 0.25 (p=0.079).
authors.affiliation: Department of Internal Medicine, Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, University and IRCCS Maggiore Hospital, Via Pace 9, Milan 20122, Italy.
authors.forename: Rossana
authors.initials: R
authors.lastname: Lombardi
authors.forename: Veena
authors.initials: V
authors.lastname: Chantarangkul
authors.forename: Marco
authors.initials: M
authors.lastname: Cattaneo
authors.forename: Armando
authors.initials: A
authors.lastname: Tripodi
mesh_terms: D000925:Anticoagulants / Q000097:blood / Q000302:isolation & purification / Q000627:therapeutic use; D001774:Blood Chemical Analysis / Q000295:instrumentation / Q000379:methods* / Q000592:standards*; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods* / Q000592:standards*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013927:Thrombosis / Q000097:blood / Q000517:prevention & control; D014859:Warfarin / Q000097:blood* / Q000302:isolation & purification* / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D014859:Warfarin