Determination of plasma concentrations of carbamazepine, oxcarbazepine and their active metabolites and investigation of serum matrix based on HPLC

Abstract To investigate the determination of carbamazepine, oxazepine and their metabolites 10, 11-epoxy carbamazepine (CBZ), 10, 11-dihydro10-hydroxyl carbamazepine (MHD) in blood by HPLC and their interfering factors. The samples were pretreated by protein precipitation method. The chromatographic conditions were as follows: Agilent Eclipse Plus C18 column (4.6 mm × 250 mm, 5 μm); Mobile phase: acetonitrile-water (30–70); Flow rate: 1 mL·min −1 ; Column temperature: 37 °C; Uv detection wavelength: 210 nm. Based on common clinical antiepileptic drugs and serum samples of high bilirubin, high lipemia and low hemolysis, the anti-interference test was established. Under the chromatographic conditions, the separation of CBE, OXC and their metabolites was good, CBZ had a good linear relationship between 0.1 and 20 mg L −1 ( r = 0.9994), and CBZE had a good linear relationship between 0.05 and 10 mg L −1 ( r = 0.9998); OXC has a good linear relationship in 0.05–20 mg L −1 ( r = 0.9993); MHD has a good linear relationship in 0.5–50 mg L −1 ( r = 0.9995). The intra-day and inter-day precision RSD<13%, and the RSD of LLOQ<19%; the stability is good, the relative recovery rate is 91.17%–118.06%, and the method validation is in line with the “Chinese Pharmacopoeia” (2020 edition). Common clinical antiepileptic drugs, hyperlipidemia, and low hemolysis serum sample matrix have no obvious interference with monitoring, but high bilirubin serum sample matrix may have interference to varying degrees. The method is sensitive, accurate, simple, rapid and economical. It can be used for blood concentration monitoring and pharmacokinetic study of CBZ, OXC and their active metabolites.