Determination of carbamazepine and carbamazepine-10,11-epoxide in human serum with HPLC

Objective To develop a method of HPLC to determine carbamazepine and carbamazepine-10,11-epoxide in human serum.Methods Samples were separated on Diamond C18(200 mm×4.6 mm,5 μm).Different ratios of methanol-water were used as the gradient eluent,and flow rate was 1.0 mL·min-1.The column temperature was 25 ℃ and detection wavelength was 215 nm.Intern standard was estazolam.Results The calibration curves were linear in the ranges of 1.08～21.60 μg·mL-1(r=0.9958)and 0.20～5.00 μg·mL-1(r=0.9952) for carbamazepine and carbamazepine-10,11-epoxide respectively;the lowest limits of assay were both 0.10 μg·mL-1.The average recoveries at three concentrations of carbamazepine were(98.5±5.1)%,(103.6±4.8)%,(100.0±4.9)%,and those of carbamazepine-10,11-epoxide were(95.8±3.6%),(99.7±2.9)%,(93.0±5.7)% respectively;RSD of the intra-day and inter-day were less than 10%.Conclusion The method is rapid,sensitive and suitable for determination of carbamazepine and carbamazepine-10,11-epoxide in human serum.