A VALIDATED HPLC METHOD FOR THE DETERMINATION OF CARBAMAZEPINE AND CARBAMAZEPINE 10,11-EPOXIDE IN HUMAN PLASMA

A validated reversed-phase high-performance liquid chromatographic (HPLC) procedure employing ultra-violet (UV) detection for the analysis of carbamazepine (Tegretol(R), CBZ) and its predominant metabolite, carbamzepine 10,11-epoxide (CBZ-E), in human plasma is reported. The method is rapid and coupled with standard HPLC procedures leads to a sensitive, accurate, and reproducible assay. The retention times of CBZ-E, CBZ, and internal standard, are 3.3, 7.0 and 10.8 minutes, respectively, with an overall chromatographic run time of 12.0 minutes. The peak height ratio versus plasma concentration is linear over the range of 0.10 to 10.0 mug/mL for each analyte and exhibits correlation coefficients of 0.9968 or better (n = 7). The mean absolute recoveries of CBZ and CBZ-E using the described assay are 89.8 and 86.8%, respectively. The inter- and intra-day accuracy and precision is within 11.6% of the actual values for all concentrations investigated. Furthermore, the assay is suitable for obtaining the AUC, C(max) and t1/2 of CBZ and CBZ-E in human plasma after a single 400 mg oral dose of Tegretol(R).