Development and Validation of Stability-Indicating UV-Spectrophotometric Methods for the Determination of Flunarazine Dihydrochloride In Dosage Form

Two sensitive, precise and cost-effective UV-spectrophotometric methods are described for the determination of flunarazine dihydrchloride (FNH) in bulk drug and tablets. The proposed methods are based on the measurement of the absorbance of FNH either in 0.1 M HCl (method A) or in acetonitrile (method B) at 253 nm. As per the International Conference on Harmonization (ICH) guidelines, the methods were validated for linearity, accuracy, precision, limits of detection (LOD) and quantification (LOQ) and robustness and ruggedness. Beer’s law is obeyed over the concentration ranges of 2.5-30.0 µg mL-1 in method A and 1.0-20.0 µg mL-1 in method B. The calculated molar absorptivity values are 2.12×104 and 2.47×104 L mol-1 cm-1 for method A and method B, respectively. The proposed methods were applied successfully to the determination of FNH in tablets with good accuracy and precision without any detectable interference from common excipients. The accuracy of the proposed methods was further assessed by the recovery studies via a standard addition method. In addition, forced degradation of FNH was conducted in accordance with the ICH guidelines. Acidic and basic hydrolysis, thermal stress, peroxide and photolytic degradation were used to assess the degradation behavior of the drug. Substantial degradation was observed during oxidative degradation and no degradation was observed under other stress conditions.