DEVELOPMENT AND VALIDATION OF HIGH PERFORMANCE LIQUID CHROMATOGRAPHY METHOD FOR SIMULTANEOUS ESTIMATION OF DEXTROMETHORPHAN HYDROBROMIDE AND QUINIDINE SULPHATE IN PHARMACEUTICAL DOSAGE FORM

The present work describes a validated reverse phase high performance liquid chromatography (RPHPLC) method for simultaneous estimation of dextromethorphan hydrobromide and quinidine sulphate in pharmaceutical dosage from. The drugs were resolved using Hemochrom Intsil C18-5U column (250×4.6) mm in isocratic mode with mobile phase methanol: water (0.08% diethylamine, 0.02% of glacial acetic acid and pH 4.4 adjusted with orthophosphoric acid) in the ratio of 70:30 V/V at a flow rate of 1.0 mL/min. Retention time of dextromethorphan hydrobromide and quinidine sulphate were 4.9±0.2 and 3.6±0.2, respectively, at 292nm. The above mentioned method was validated as per International Conference on Harmonization (ICH) guidelines. Linear responses were obtained in concentration ranges of 5-35 μg/mL for dextromethorphan hydrobromide and 4-16 μg/mL for quinidine sulphate, with correlation coefficient (r2) of 0.999 for both the drugs. A simple, selective, accurate, precise, robust and reliable RP-HPLC method thus developed and validated for simultaneous estimation of dextromethorphan hydrobromide and quinidine sulphate.