Determination of Oxcarbazepine and Its Active Metabolite 10-Hydroxycarbamazepine in Human Serum by LC-MS/MS and Its Clinical Application

OBJECTIVE To establish a LC-MS/MS method for simultaneous determination of oxcarbazepine(OXC) and its active metabolite 10-hydroxycarbamazepine(MHD) in human serum and apply it to the determination of clinical drug concentration. METHODS Serum samples with cabozantinib as internal standard, were determined by LC-MS/MS after acetonitrile treatment. The chromatographic conditions were as following:column was Waters BEH C₁₈(2.1 mm×150 mm, 1.7 µm), temperature was 40℃, mobile phase consisted of 0.1% formic acid and acetonitrile, flow rate was 0.3 mL·min^-1, injection volume was 1 µL. The serum samples was detected by electrospray postive ion source in MRM mode. The detection ion pairs were OXCM-H⁺m/z 253.2→180.1, MHDM-H⁺m/z 255.3→194.2. RESULTS The serum concentration of OXC and MHD had a good linear relationship in the range of 0.01-1 µg·mL^-1(r²=0.995 8), 0.4-40 µg·mL^-1(r²=0.996 2), respectively. Accuracy ranged from 85% to 115%. The intra-day RSD and inter-day RSD were both < 15%. The extraction recoveries of OXC and MHD were 90.75%-100.43% and 80.40%-82.30%, respectively. The method was not affected by matrix effect. It was stable at room temperature, repeated freeze-thaw and long-term storage, and the RSD was < 15%. The drug concentration of 60 patients were determined by established method, and the median of OXC and MHD concentration were 0.48 and 17.1 µg·mL^-1, respectively. CONCLUSION This method is simple, rapid, accurate and sensitive. It is applicable to the monitoring of the clinical serum concentration of OXC and MHD. It can also provide detection technology for individualized drug therapy.