DEVELOPMENT AND VALIDATION OF LIQUID CHROMATOGRAPHIC METHOD FOR SIMULTANEOUS ESTIMATION OF STRYCHNINE AND GALLIC ACID

An accurate, precise and robust RP-HPLC method was developed for the simultaneous estimation of strychnine and gallic acid. The markers were resolved using HiQ C18HS column with methanol and potassium dihydrogen phosphate buffer (10 mM, pH 3) (60:40 V/V) as mobile phase at flow rate of 1 mL per minute and run time of 6 minutes. Retention times of strychnine and gallic acid were 3 and 4.7 minutes, respectively at 264 nm. The linearity range for strychnine and gallic acid was found to be 0.5-3 μg/mL and 1-3.5 µg/mL, respectively with coefficient of linear regression greater than 0.99 for both the markers. The developed method was validated as per ICH Q2 (R1) guidelines and the results obtained were satisfactory. The method was applied for quantification of markers in marketed and In-house formulations of Agnitundi Vati, a polyherbal ayurvedic formulation. The developed method thus could be used for standardization of Agnitundi Vati and other herbal preparations containing these two markers.