RESUMEN
Objective: To establish an ultra performance liquid chromatography-tandem quadrupole mass spectrometry ( UPLC-MS/MS) method to determine the concentration of carbamazepine and phenobarbital in human plasma, and apply in the clinical moni-toring. Methods:Diazepam was used as the internal standard, and the samples were precipitated by acetonitrile. An ACQUITY UPL-C? BEH C18 (50 mm × 2. 1 mm, 1. 7 μm) column was used as the stationary phase at 40℃ with a Waters XEVO TQD. The mobile phase consisted of acetonitrile (containing 10 mmol·L-1 ammonium formate) and water (containing 10 mmol·L-1 ammonium for-mate and 0. 1% formic acid) with gradient elution pumped at a flow rate of 0. 4 ml·min-1 . ESI was applied and the samples were scanning analyzed by positive ion multi-reaction monitoring mode. The plasma was precipitated by 200 μl acetonitrile and centrifugated at 12 000 × g for 10 min and tranfer it into an Ep tube. The sample size was 20 μl. Results:The retention time of carbamazepine was 1. 23 min. Excellent linear calibration curves of carbamazepine were obtained within the concentration range of 0. 25-25μg·ml-1(r=0. 999 7). The lower limit of quantification of carbamazepine was 0. 01 μg·ml-1. The retention time of phenobarbital was 1. 11 min. Excellent linear calibration curves of carbamazepine were obtained within the concentration range of 0. 5-50 μg·ml-1(r=0. 999 6). The lower limit of quantification of carbamazepine was 0. 05 μg·ml-1. The recovery of three concentrations of carbamazepine was (82. 1 ± 6. 83)%, (82. 91 ± 4. 3)% and (84. 35 ± 3. 09)%, and the recovery of three concentrations of phenobarbital was (84. 27 ± 6. 91)%, (84. 32 ± 7. 74)% and (89. 07 ± 6. 24)%, respectively. The intra- and inter-day RSDs were all less than 10%. There were no endogenous substances existing in the incubation system, therefore, there was no interference with the determination. Conclu-sion:The simple, accurate and rapid method is suitable for the determination of carbamazepine and phenobarbital in human plasma, which can contribute greatly to the therapeutic drug monitoring service for patients.