Sensitive methods for the determination of the cyclophosphamide metabolites nornitrogen mustard, 4-ketocyclophosphamide and carboxyphosphamide are presented. After liquid-liquid extraction and derivatization, the metabolites are determined by gas chromatography and thermionic specific detection. The methods were used to study the in vitro biotransformation of cyclophosphamide with S-9 liver fractions of human donors. The results show large interindividual differences in the formation of nornitrogen mustard and carboxyphosphamide. 4-Ketocyclophosphamide was not detected.
Chromatography, Gas Cyclophosphamide