Development and Validation of HPLC Method for Estimation of Oxcarbazepine in Spiked Human Plasma: Synthesis and Characterization of Its Active Metabolite

Abstract

A simple, precise and accurate HPLC-UV method was developed and validated for the quantitation of oxcarbazepine (OXZ) in human plasma. The OXZ and erlotinib (ERL) (internal standard) were extracted from human plasma using liquid-liquid extraction. The extraction efficiency of drug and internal standard from plasma were evaluated in different organic solvents and effect of pH modifier were studied. The separation was achieved on C18 (250 × 4.6 mm, 5 μm) column using methanol: 20 mM potassium phosphate buffer (pH 3.0) (60:40 %, v/v) at 237 nm. The flow rate was kept constant at 1mL/min throughout the analysis. To select the optimal calibration model, different weighting factors were evaluated. The calibration model with weighing factor, 1/x2was found optimal with minimum % relative error and most random distribution around x-axis. The calibration curve was linear in the range of 100-3200 ng/mL. The method was validated as per US-FDA guidelines with respect to selectivity, accuracy, precision, % recovery and stability. Further, the 10,11-dihydro-10-hydroxy carbamazepine (10-MHD); active metabolite of OXZ was synthesized and characterized by GC-MS. The extraction efficiency of10-MHDin human plasma was compared with OXZ using optimized LLE method.