title: High-performance liquid chromatographic determination of stabilized 4-hydroxyifosfamide in human plasma and erythrocytes.
abstract: A method using reversed-phase high-performance liquid chromatography (RP-HPLC) is described for the measurement of the stabilized activated metabolite of ifosfamide, 4-hydroxyifosfamide (4-OHIF), in human plasma and erythrocytes. Immediately after sample collection and plasma-erythrocyte separation at 4 degrees C, 4-OHIF was stabilized by derivatization with semicarbazide (SCZ). The sample pretreatment involved liquid-liquid extraction with ethyl acetate. RP-HPLC was executed with a C8 column and acetonitrile-0.025 M potassium dihydrogenphosphate buffer (pH 7.40)-triethylamine (13.5:86:0.5, v/v) as mobile phase. The analyte was determined with UV detection at 230 nm. Complete validation, optimisation and stability studies were performed and the method proved to be specific, sensitive and with a stable analyte in the range of clinically relevant concentrations (0.1-10 microg/ml) after conventional dosing. The lower limit of quantitation was 100 ng/ml using 1.00 ml of sample. Accuracy was between 94.1 and 107.0%. Within-day and between-day precisions were less than 6.2% and 7.2%, respectively. 4-OHIF-SCZ was found to be stable in the biological matrix at -20 degrees C for at least 1 month. A pharmacokinetic study conducted in a patient receiving 9 g/m2 over 3 days by means of a continuous infusion, demonstrated the applicability of this method.
authors.affiliation: Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute/Slotervaart Hospital, Amsterdam.
authors.forename: T
authors.initials: T
authors.lastname: Kerbusch
authors.forename: A D
authors.initials: AD
authors.lastname: Huitema
authors.forename: J J
authors.initials: JJ
authors.lastname: Kettenes-van den Bosch
authors.forename: H J
authors.initials: HJ
authors.lastname: Keizer
authors.forename: J
authors.initials: J
authors.lastname: Ouwerkerk
authors.forename: J
authors.initials: J
authors.lastname: de Kraker
authors.forename: J H
authors.initials: JH
authors.lastname: Beijnen
mesh_terms: D000097:Acetonitriles; D002021:Buffers; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004355:Drug Stability; D004912:Erythrocytes / Q000737:chemistry*; D006801:Humans; D007069:Ifosfamide / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use; D007202:Indicators and Reagents; D013058:Mass Spectrometry; D012663:Semicarbazides; D012680:Sensitivity and Specificity
chemical_list: D000097:Acetonitriles; D002021:Buffers; D007202:Indicators and Reagents; D012663:Semicarbazides; C010059:carbamylhydrazine; C039771:4-hydroxyifosfamide; D007069:Ifosfamide; C032159:acetonitrile