[Determination of ubenimex in human plasma by HPLC-MS/MS].

To establish a liquid chromatography tandem mass spectrometry method for the determination of ubenimex in human plasma. The essay was conducted with an API 3000 HPLC-MS/MS system consisted of a Ultimate C18 column (50 mm x 4.6 mm, 5 microm). The mobile phase consisted of methanol-water-formic acid (70 : 30 : 0.05, V/V/V) at a flow rate of 0.2 mL/min. Granisetron was used as the internal standard. The sample was extracted by solid phase extraction column and was operated under the multiple reaction monitoring mode using the electrospray ionization technique in positive mode. The linear range of ubenimex was 0.4-4000 ng/mL. The limit of quantity was set at 0.4 ng/mL. The within-day and between-day variations were less than 6%. This method for the quantitative determination of ubenimex was proved to be accurate, sensitive, selective and convenient and can be applied in the determination of ubenimex in human plasma.