A green HPLC method for the analysis and stability study of flavoxate HCl using micellar eluent
Abstract
An accurate, reliable and environmentally benign stability-indicating micellar liquid chromatographic method was developed and validated for the determination of flavoxate HCl (FLV) in presence of its stress induced degradation products. Good resolution of FLV from its degradation products was achieved using a reversed phase BDS Hypersil phenyl column (4.6 mm × 250 mm, 5 μm particle size) with a micellar mobile phase consisting of 0.15 M sodium dodecyl sulphate, 15% n-propanol, 0.3% triethylamine and 0.02 M orthophosphoric acid (pH 2.5). UV quantitation was set at 325 nm. The linear regression analysis data for the calibration plot of FLV showed a good linear relationship over the concentration range of 2.0–40.0 μg mL−1 with lower detection limit of 0.40 μg mL−1. Stability of FLV was investigated as per ICH-prescribed stress conditions including acidic, alkaline, neutral, oxidative and photolytic conditions. Significant degradation of FLV was observed under all studied stress conditions. A kinetic study was conducted to investigate the oxidative degradation of FLV at different temperature settings; reaction rate constants, half-life times and activation energy were calculated. A proposal for the degradation pathways was also postulated. The proposed method was applied for the assay of FLV in its commercial tablets with mean percentage recovery of 99.80 ± 1.41. Statistical comparison of the results of the proposed method with those obtained by the comparison method revealed no significant differences in the performance of the two methods regarding accuracy and precision.