title: Determination of N,N',N"-triethylenethiophosphoramide and its active metabolite N,N',N"-triethylenephosphoramide in plasma and urine using capillary gas chromatography.
abstract: A sensitive assay for the determination of N,N',N"-triethylenethiophosphoramide (thioTEPA) and its metabolite N,N',N"-triethylenephosphoramide (TEPA) in micro-volumes human plasma and urine has been developed. ThioTEPA and TEPA were analysed using gas chromatography with selective nitrogen-phosphorus detection or mass spectrometry after extraction with a mixture of 1-propanol-chloroform from the biological matrix. Diphenylamine was used as internal standard. The limit of detection was 1.5 ng/ml for thioTEPA and 2.5 ng/ml for TEPA, using 100 microl of biological sample; recoveries ranged between 70 and 90% and both accuracy and precision were less than 10%. Linearity was accomplished in the range of 10-1000 ng/ml for plasma and 100-10000 ng/ml for urine using thermionic nitrogen-phosphorus detection. With mass spectrometry a linear range of 100-25000 ng/ml TEPA in plasma or urine was obtained. For thioTEPA a second-order polynomial function describes the relationship between the analyte concentration in the range of 500-25000 ng/ml and detection response. TEPA proved to be stable in plasma and urine for at least 10 weeks at -80 degrees C. ThioTEPA and TEPA plasma concentrations of two patients treated with thioTEPA are presented demonstrating the applicability of the assay for clinical samples.
authors.affiliation: University of Utrecht, Department of Pharmaceutical Analysis, The Netherlands.
authors.forename: R J
authors.initials: RJ
authors.lastname: van Maanen
authors.forename: R D
authors.initials: RD
authors.lastname: van Ooijen
authors.forename: J W
authors.initials: JW
authors.lastname: Zwikker
authors.forename: A D
authors.initials: AD
authors.lastname: Huitema
authors.forename: S
authors.initials: S
authors.lastname: Rodenhuis
authors.forename: J H
authors.initials: JH
authors.lastname: Beijnen
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D006801:Humans; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013852:Thiotepa / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D013721:Triethylenephosphoramide / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine
chemical_list: D013852:Thiotepa; D013721:Triethylenephosphoramide