Analytical method development and validation of simultaneous estimation of dosulepin and methylcobalamin in tablet dosage form by RP-HPLC

A sensitive, selective and precise high performance liquid chromatographic method has been developed and validated for the simultaneous determination of Dosulepin and Methylcobalamin in tablet dosage form. The method employed waters xterra C8 column (150 x 4.6 mm , 5 μm particle size) as the stationary phase while Acetonitrile, 0.1 M H3PO4 (70:30,v/v) was used as mobile phase. The Retention time of Dosulepin and Methylcobalamin were observed to be 1.89and 2.85 minutes, respectively. The flow rate was found to be 1ml/min and effluents were monitored at 222 nm. The linear regression analysis data for the calibration plots showed a good linear relationship for Dosulepin and Methylcobalamin over a concentration range of 150-450 μg/ml and 3-9 μg/ml respectively with correlation co-efficient of 0.999 for Dosulepin and 0.999 for methylcobalamin. The LOQ was found to be 9.23 and 9.57 μg/ml respectively for Dosulepin and Methylcobalamin. The method was validated as per ICH guideline and it was found to be accurate, precise and robust. Marketed formulation was analyzed successfully.