Establishment of a concentration test method of S-071031B in rat plasma and its pharmacokinetics

Objective To establish an LC-MS/MS method for determination of S-071031B,a novel antidepressant,in rat plasma and to study its pharmacokinetic profiles. Methods An LC-MS / MS method was established to determine S-071031B in rat plasma,and L-8021 was employed as the internal standard. The analytes were separated on a C18column with a mobile phase consisting of water-acetonitrile containing 0. 1%( v / v) formic acid at a flow rate of 0. 3 ml / min. The mass spectrometer was operated in a selected reaction monitoring( SRM) mode with a positive electrospray ionization( ESI) interface. The plasma concentration-time curve was drawn and pharmacokinetic parameters were calculated by DAS2. 0. Results The linear range was from 2 to 1000 ng / ml with a sensitivity of 2 ng / ml as the lower limit of quantification.The intra-day and inter-day precisions,recoveries and matrix effects at three spiked levels were all suited to the determination of biological samples. After oral administration of S-071031B,the C max of S-071031B was( 287. 2 ± 50. 8) μg / L and the T max was( 0. 8 ± 0. 3) h,with a t1 /2of( 2. 9 ± 0. 6) h and an AUC( 0-∞)of( 1372. 6 ± 255. 3) μg / L·h. Conclusion This method is sensitive and specific enough for determination of S-071031B in rat plasma to facilitate the study of its pharmacokinetics.