Development and Validation of a Stability Indicating Rp-lc Method for the Estimation of Process Related Impurities and Degradation Products of Dipyridamole Retard Capsules

A novel stability-indicating gradient reverse phase liquid chromatographic method was developed for the quantitative determination of process related impurities and forced degradation products of Dipyridamole in Dipyridamole retard capsules. This method is able separate all seven known impurities which includes two newly identified potential degradant impurities.The method was developed by using Inertsil ODS-2 (150mm x 4.6mm) 5μm column with mobile phase containing a gradient mixture of solvent A (0.007 M potassium dihydrogen phosphate, pH adjusted to 7.0 with 5% sodium hydroxide solution) and solvent B (methanol).The flow rate was 1.0 mL/min with column temperature of 45°C and detection wavelength at 295nm. Dipyridamole was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. Dipyridamole was found to degrade in all the condition where significantly degrade in acid, oxidative stress conditions and Humidity conditions. The degradation products were well resolved from Dipyridamole and its impurities, thus proved the stability-indicating power of the method. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness.