DEVELOPMENT AND VALIDATION OF A STABILITY-INDICATING RP-HPLC METHOD FOR THE ESTIMATION OF DIACEREIN IMPURITIES IN API AND PHARMACEUTICAL FORMULATION

A sensitive, stability-indicating gradient RP-HPLC method has been developed for the quantitative determination of impurities of Diacerein in API and pharmaceutical formulation. Efficient chromatographic separation was achieved on a Hypersil BDS C18, 250 × 4.6 mm, 5 µm column with mobile phase containing a gradient mixture of solvents A and B. The flow rate of the mobile phase was 1.0 mL min−1 with column temperature of 40°C and detection wavelength at 254 nm. The relative response factor values of Rhein, Aloe Emodin, Monoacetyl Rhein I, and Monoacetyl Rhein II were 0.86, 0.80, 0.81, and 0.89, respectively. Diacerein formulation sample was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal, and photolytic degradation. Diacerein was found to degrade significantly in acid, base, and peroxide stress conditions. The degradation products were well-resolved from Diacerein and its impurities. The peak purity test results confirmed that the Diacerein peak was homogenous and pure in all stress samples and the mass balance was found to be more than 98%, thus proving the stability-indicating power of the method. The developed method was validated according to ICH guidelines with respect to specificity, linearity, limits of detection and quantification, accuracy, precision, and robustness.