Simultaneous Determination of Carbamazepine and its Active Metabolite Carbamazepine-10,11-epoxide in Human Plasma by UPLC

摘要

A simple method for the determination of carbamazepine and its active metabolite carbamazepine-10,11-epoxide by ultra performance liquid chromatography (UPLC) with ultraviolet absorbance detection (TUV) was developed. The method involves a two-step protein precipitation by liquid–liquid extraction. Phenytoin sodium was used as the internal standard. The separation was carried out on Acquity C18 column with acetonitrile:methanol:KH2PO4 buffer (adjusting pH to 4.6 with 85% o-phosphoric acid) (180/180/170, v/v/v) as the mobile phase at a flow rate of 0.4 mL min?1. Linear detection response was obtained for concentrations ranging from 50 to 5,000 ng mL?1. The limit of quantification (LOQ) was 50 ng mL?1. The method was validated successfully for the determination of carbamazepine and its active metabolite carbamazepine-10,11-epoxide, which can be applied through pharmacokinetics and bioequivalence studies.