Study on Simultaneous Analysis of Six Antiepileptic Drugs and Two Active Metabolites in Human Plasma by HPLC

OBJECTIVE To establish a simple HPLC method for the simultaneous determination of primidone (PRI), lamotrigen (LTG), phenobarbital (PB), phenytoin(PHT), oxcarbazepine (OXC), carbamazepine(CBZ) and two active metabolites of monohydroxycar bazepine (MHD), carbamazepine 10,11-epoxide(CBZE) in human plasma.METHODS The analytes were extracted by protein precipitation, using propranolol hydrochloride as internal standard. The extracts were injected onto an Agilent RX-C_ 8 column, and the mobile phase consisted of methanol-acetonitril-0.1% triflouroacetic acid (20∶13.5∶66.5). PRI, LTG, MHD, PB and CBZE were detected at the wavelength of 215 nm, while OXC, PHT and CBZ were detected at 235 nm.RESULTS The method was found to be linear over the concentration ranges investigated, 5～50 mg·L~ -1 for PRI,1～25 mg·L~ -1 for LTG,1～50 mg·L~ -1 for MHD,5～100 mg·L~ -1 for PB, 1～10 mg·L~ -1 for CBZE,0.5～25 mg·L~ -1 for OXC, 1～50 mg·L~ -1 for PHT and 1～25 mg·L~ -1 for CBZ. The recoveries of PRI, LTG, MHD, PB, CBZE, OXC, PHT and CBZ were 98.7%, 97.0%, 97.9%, 102.9%, 100.0%, 99.2%, 100.1% and 101.7%, respectively. The intra-and inter-day validation were adequate with the RSDs of 11.6% or below. CONCLUSION This method is proved to be convenient, accurate and suitable to measure concentrations of the eight analytes in clinical samples.