A Stability Indicating Assay Method for the Simultaneous Estimation of Doxylamine Succinate and Pyridoxine Hydrochloride in Bulk and Combined Dosage Form

A simple, rapid, sensitive and new RP-HPLC method was developed and validated concerning ICH guidelines for simultaneous assessment of doxylamine succinate (DOXY) and pyridoxine hydrochloride (PYRI) in bulk and combined dosage form. Isolation was performed on C18 column, using phosphate buffer (pH 4.0) and acetonitrile (70:30) as mobile phase, flow rate at 1ml/min. Retention times were 4.256 min and 2.400 min for DOXY and PYRI respectively. Linearity for both drugs were in the concentration range of 10-50µg/ml. Correlation coefficients were 0.999 and 0.999 for DOXY and PYRI respectively. Method was validated according to the parameters of ICH guidelines.The accelerated stability study was conducted as per the ICH guidelines. Study suggests that both the drugs were most stable in photolytic condition. DOXY was more susceptible in basic condition whereas in oxidation condition PYRI was more susceptible. Results obtained were quite satisfactory for this method and this method can be suitable for the estimation of DOXY and PYRI in any formulation along with degradation product.