Abstract: ［Abstract］ Objective〖HTSS〗To establish a high performance liquid chromatography tandem mass spectrometry(LC-MS) method for the determination of primidone in human plasma and to apply it to the determination of plasma concentration in patients with epilepsy.
〖HTH〗〖WTHZ〗Methods〖HTSS〗Column: Phenomenex Kinetex XB-C18 （50 mm×3 mm，2.6 μm）. Mobile phase: methanol(A)-2% A acid water(B) for gradient elution. Flow rate: 0.4 mL/min. Column temperature:40 ℃. Sample volume: 5 μL. The internal standard was caffeine. The electrospray ion source was used for positive ion mode monitoring and the multi-reaction monitoring mode was used for quantitative analysis. The injection voltage of the source was 5 500 V and the temperature of the ion source was 600 ℃.The specificity, standard curve and lower limit of quantification, precision, recovery, stability and matrix effect of the method were investigated. Selection of 20 epileptic patients with oral primidone（the initial dose was 50 mg, 2 times a day after 3 days, 3 times a day after 1 week, 250 mg at the beginning of the 10 th day, 3 times a day),two weeks later, early in the morning, venous blood was taken for 2 mL. The plasma concentration of prochloramil was determined by LC-MS/MS.
〖HTH〗〖WTHZ〗Results〖HTSS〗The internal linear relationship of prometone was good between 1-5 mg/L, and the lowest quantitative lower limit is 0.01 mg/L. The average recovery was more than 95%, the relative standard deviation values of inter-day and intra-day precision were less than 15%, and the stability was good. The blood samples of 20 epileptic patients were determined by this method. The blood concentration range was 8.75-36.88 mg/L.
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗This method is convenient, rapid, specific, sensitive and accurate. It can be used to determine the concentration of propranone in plasma of epileptic patients.

Key words: epileptic, primidone, tandem mass spectrometry, plasma concentration