title: Enantioselective liquid chromatography-mass spectrometry assay for the determination of ifosfamide and identification of the N-dechloroethylated metabolites of ifosfamide in human plasma.
abstract: A sensitive and specific liquid chromatography-mass spectrometry (LC-MS) method has been developed and validated for the enantioselective determination of ifosfamide [(R)-IF and (S)-IF] in human plasma and for the detection of the N-dechloroethylated metabolites of IF, 2-N-dechloroethylifosfamide [(R)-2-DCl-IF and (S)-2-DCl-IF] and 3-N-dechloroethylifosfamide [(R)-3-DCl-IF and (S)-3-DCl-IF]. IF, 2-DCl-IF and 3-DCl-IF were extracted from plasma using solid-phase extraction and resolved by liquid chromatography on a column containing a Chirabiotic T chiral stationary phase. The enantioselective separations were achieved using a mobile phase composed of 2-propanol:methanol (60:40, v/v) and a flow rate of 0.5 ml/min. The observed enantioselectivities (alpha) for IF, 2-DCl-IF and 3-DCl-IF were 1.20, 1.17 and 1.20, respectively. The calibration curve was linear in the concentration range of 37.50-4800 ng/ml for each ifosfamide enantiomer (r(2)>0.997). The lower limit of detection (LLOD) was 5.00 ng/ml. The inter- and intra-day precision ranged from 3.63 to 15.8% relative standard deviation (R.S.D.) and 10.1 to 14.3% R.S.D., respectively, and the accuracy ranged from 89.2 to 101.5% of the nominal values. The method was applied to the analysis of plasma samples obtained from a cancer patient who received 3.75 g/m(2)/day dose of (R,S)-ifosfamide as a 96-h continuous infusion.
authors.affiliation: Laboratory of Clinical Investigation, Gerontology Research Center, National Institute on Aging, NIH, Baltimore, Maryland, USA. oliveirarv@dq.ufscar.br
authors.forename: Regina V
authors.initials: RV
authors.lastname: Oliveira
authors.forename: Joelle M
authors.initials: JM
authors.lastname: Onorato
authors.forename: Danuta
authors.initials: D
authors.lastname: Siluk
authors.forename: Christine M
authors.initials: CM
authors.lastname: Walko
authors.forename: Celeste
authors.initials: C
authors.lastname: Lindley
authors.forename: Irving W
authors.initials: IW
authors.lastname: Wainer
mesh_terms: D002853:Chromatography, Liquid / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007069:Ifosfamide / Q000031:analogs & derivatives* / Q000097:blood / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction; D013237:Stereoisomerism
chemical_list: C038007:dechloroethylifosfamide; D007069:Ifosfamide