RESUMEN
OBJECTIVE: To establish a simple and rapid HPLC method for the determination of serum concentration of isofosfamide.METHODS: With cyclophosphamide as internal standard,the serum sample was extracted on C18 solid phase extraction column and determined on Zorbox-ODS C18 at room temperature.The mobile phase consisted of acetonitrile-water(25∶75) at a flow rate of 1 mL?min-1 and a detection wavelength of 200 nm.RESULTS: The linear range of ifosfamide was 2.5～200 ?g?mL-1(r=0.999 9),with the lowest detectable limit at 0.5 ?g?mL-1(S/N=3).Both the intraday and interday RSD were less than 5%.The extraction recoveries of ifosfamide at high,middle and low concentrations were ranged between 89.3% and 93.6% versus 77.6%～82.3% in chloroform-treated serum samples.CONCLUSION: The method which uses the C18 solid phase extraction column is of high recovery,and the sample treatment by which is simple,rapid,accurate,and pollution-free,and it is applicable for the monitoring of serum concentration and pharmacokinetic study of isofosfamide.