ALKALINE DEGRADATION KINETICS AND STABILITY INDICATING RP-HPLC METHOD FOR THE ESTIMATION OF FLAVOXATE HYDROCLORIDE IN BULK AND PHARMACEUTICAL DOSAGE FORMSAbstract
A simple stability indicating reversed-phase HPLC method was developed, validated and subsequently alkaline degradation kinetics are also determined for the estimation of Flavoxate Hydrocloride (FVH) present in pharmaceutical dosage forms. The proposed RP-HPLC method utilizes a LiChroCART – Lichrosphere 100, C18 RP column Hibar® (250 × 4 mm, 5 μm) in an isocratic separation mode with mobile phase consisting of methanol and water in the proportion of 50:50% (v/v), at a flow rate of 0.8 ml / min and the effluent was monitored at 315 nm. The retention time of FVH was found to be 2.92 min. Stability of FVH was investigated as per ICH – prescribed stress conditions including acidic, alkaline, thermal, oxidative and photolytic conditions. Significant degradation of FVH was observed under all studied stress conditions. A kinetic study was conducted to investigate the alkaline degradation of FVH at different temperatures; reaction rate constants, half-life times and activation energy were calculated. The described method was linear over a range of 1 – 300 µg/ml. The percentage recovery was 99.46. F-test and t-test at 95% confidence level was used to check the intermediate precision data obtained under different experimental setups; the calculated value was found to less than the critical value.