Development of a rapid and sensitive liquid chromatography/tandem mass spectrometry method for the determination of 1,2‐[bis(1,2‐benzisoselenazolone‐3(2H)‐ketone)]‐ethane (BBSKE), a novel anti‐cancer agent in rat plasma

A rapid and sensitive liquid chromatography/electrospray ionization tandem mass spectrometric (LC/ESI‐MS/MS) method has been developed to determine 1, 2‐[bis(1,2‐benzisoselenazolone‐3(2H)‐ketone)]‐ethane (BBSKE), a novel antineoplastic agent, in rat plasma. The analytes were separated on a C 18 column with a mobile phase of methanol–water (75:25, v/v) and detected using a triple‐quadrupole mass spectrometer in positive mode with the selective reaction monitoring. The characteristic ion dissociation transitions were m/z 603.0 → 448.9 for derivatized BBSKE and m/z 631.0 → 476.8 for derivatized internal standard. The assay was linear over a range of 1–1000 ng/mL with a lower limit of quantification of 1 ng/mL. Intra‐ and inter‐day precisions were less than 9.6 and 5.0%, respectively, and the accuracy ranged from −5.2 to 4.0%. The validated method was successfully applied to the characterization of pharmacokinetic profile of BBSKE after oral administration in rats. Copyright © 2008 John Wiley & Sons, Ltd.