Validated Reversed-Phase Liquid Chromatographic Method for Simultaneous Determination of Dextromethorphan and Chlorpheniramine in Non-biological and Biological Matrices Using PDA Detector

A simple, precise and sensitive reversed-phase HPLC method using Photo-diode array detector for simultaneous determination of dextromethorphan (DXM) and chlorpheniramine (CLP) in various matrices had been developed and validated. The separation was achieved within 8 minutes on a C-18 column (15 cm x 4.6 mm x 5 μm) using methanol/ pH 3.0 potassium dihydrogen phosphate buffer (60:40, v/v) mobile phase in an isocratic elution mode with flow rate 0.8 mL/min and UV-detection at 230 nm. External standard was employed for quantification. The current method demonstrated good linearity ranged 1-200 μg/mL for CLP (retention time 3.83 ± 0.10 min) with r2 of 0.9994 and 2-1000 μg/mL for DXM (retention time 5.02 ± 0.10 min) with R2 of 0.9993. The limits of detection and quantification were 0.25 μg/mL and 1.0 μg/mL for CLP and 0.50 μg/mL and 1.5 μg/mL for DXM. No interference from matrices was observed and samples remained stable in the HPLC injector for 12 h. The developed method was accurate that employed a simple liquid/liquid extraction procedure with recovery ranged 90.0%-101.9% for both analytes. Intra and inter-day precision were less than 2.5%. The method was proved robust and reproducible that is applicable to pharmaceutical (active raw materials, syrups) and biological (blood) matrices.