Objective To establish an LC-MS/MS method for determination of S-071031 B, 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 C18 column 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 DAS 2.0.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 determina-tion of biological samples.After oral administration of S-071031B, the Cmax of S-071031B was (287.2 ±50.8) μg/L and the Tmax 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-071031 B in rat plasma to facilitate the study of its phar-macokinetics .

BACKGROUNDTo explore the sequential variation of pulmonary flow spectrum and its value on evaluation of risk for pulmonary resection in perioperative patients with lung cancer.

METHODSForty-nine patients with lung cancer who underwent pneumonectomy (12 cases) and lobectomy (37 cases) were observed for the values of Doppler pulmonary flow spectrum before operation, on the 3-5 days and 8-10 days postoperatively. Moreover the patients were divided into different groups according to the different operative procedures and with or without postoperative cardiac arrhythmia.

RESULTSDoppler pulmonary flow spectrum changed in all cases who underwent pneumonectomy and lobectomy from 3 to 5 days postoperatively. These changs included prolonged preejection period (PEP), shortened acceleration time (ACT), increased PEP/ACT ratio, increased pulmonary artery mean pressure (PAMP), and increased pulmonary vascular resistance (PVR). There were significant differences comparing with those before operation ( P < 0.01). The patients who underwent lobectomy recovered to the same level of pre operation on the 8th to 10th postoperative days. However, the changes of pulmonary flow spectrum continuously existed in the patients who underwent pneumonectomy on the 8th to 10th postoperative days. There were significant differences of pulmonary flow spectrum between patients with postoperative arrhythmia and without postoperative arrhythmia before operation.

CONCLUSIONSPulmonary hemodynamic obviously changes after pulmonary resection in the patients with lung cancer and the changes last longer in pneumonectomy patients. Patients with postoperative cardiac arrhythmia have marked pulmonary hemodynamic changes before operation. Doppler pulmonary flow spectrum can not only be used to analyse the pulmonary hemodynamic changes for those cases undergoing pulmonary resection after operation, but also to evaluate the risk of pulmonary resection before operation.