A novel RP-HPLC method has been developed for the simultaneous determination of Gamendazole and its process impurities and degradation impurities. Chromatographic separation was achieved on a C18 column (size: 250mmx4.6mm; 5 mu m particle size) using a gradient program at a flow rate of 1.0mL/min and an injection volume of 10 mu L with 210nm detection. The mobile phase was water-acetonitrile (pH of water was adjusted to 3.0 with orthophosphoric acid) through gradient elution. The product was subject to stress conditions like acid, base, peroxide, thermal, and photolytic degradation. Similar degradants were observed in acid and base degradation. No degradants were observed in peroxide degradation. Several new degradants were observed in photolytic degradation. However, no interference was observed due to degradation impurities and Gamendazole, known impurities and unknown impurities. As part of the method validation, specificity, limit of detection (LOD), limit of quantitation (LOQ), linearity, accuracy, precision, robustness, and ruggedness were determined. LOQ values for Gamendazole, Impurity-A, Impurity-B, and Impurity-C were 0.04%, 0.04%, 0.02%, and 0.04%, respectively. Good linearity (r(2)>0.99) was obtained ranging from LOQ to 150%. Recovery was verified for all impurities at concentrations ranging from LOQ to 150%. %Recovery for Impurity-A, Impurity-B, and Impurity-C were 99.7-107.1%, 99.1-108.9%, 98.6-107.2%, respectively.
