Abstract

A rapid stability indicating LC method for zonisamide using RR-LC

Author(s): P.Raghuram, I.V.Soma Raju, J.Sriramulu

A simple, sensitive isocratic RR-LC method has been developed for the quantitative determination of Zonisamide Related compounds in bulk drug, used as Anticonvulsant. The developed method is also applicable for the Assay determination. Efficient chromatographic separation was achieved on a C18 stationary phase with simple mobile phase combination delivered in a isocratic mode and quantification was carried out using ultraviolet detection at 240 nm at a flow rate of 1.5 mL min-1. In the developed RRLC method the resolution between Zonisamide and its two potential impurities was found to be greater than 4.0. Regression analysis shows an r value (correlation coefficient) of greater than 0.999 for Zonisamide and it’s all the two impurities. This method was capable to detect all two impurities of Zonisamide at a level of 0.01%with respect to test concentration of 1.0 mg mL-1 for a 5L injection volume. The inter and intraday precision values for all two impurities and for Zonisamide was found to be within 2.0 %RSD at its specification level. The method has shown good and consistent recoveries for Zonisamide two impurities (98.2-102.3%). The test solution was found to be stable in diluent for 48 h. The drug was subjected to stress conditions of exposure to acid hydrolysis and base hydrolysis, oxidataion, Humidity, Photolysis and thermal degradation. Considerable degradation was found to occur in acid hydrolysis stress conditions. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.9 %. The developed RR-LC method was validated with respect to linearity, accuracy, precision and robustness.