Analysis of ifosforamide mustard, the active metabolite of ifosfamide, in plasma

Ifosforamide mustard is the active metabolite of ifosfamide, a cytostatic drug. In this study a sensitive and selective method for the analysis of ifosforamide mustard in plasma is described. The method consists of direct derivatisation of ifosforamide mustard in plasma with diethyldithiocarbamate and subsequent solid-phase extraction of the resulting derivative. The analysis of the derivatisation product was performed by high-performance liquid chromatography with UV detection. The calibration graph was linear in the concentration range 0.45-45 microM and the minimum detectable concentration was 0.45 mumol. The samples were stabilised by addition of semicarbazide and sodium chloride. A patient's plasma sample was analysed by means of the described method. The ifosforamide mustard concentration was 2.3 microM.