DEVELOPMENT OF RP-HPLC METHOD FOR SIMULTANEOUS EVALUATION OF UNIFORMITY OF DOSAGE UNITS FROM ASPIRIN AND DIPYRIDAMOLE EXTENDED-RELEASE CAPSULES

The aim of the present study is to develop a stability-indicating reverse-phase high-performance liquid chromatography method for the simultaneous estimation of Aspirin and Dipyridamole in combined extended-release dosage form 25/200mg, using a single unit of the capsule. Materials and Methods: Chromatographic separation was achieved with Agilent’s high-performance liquid chromatography and X bridge C₈ column, with the mobile phase containing a mixture of ammonium dihydrogen phosphate buffer (pH 2.5): methanol (550:450, v/v) by isocratic elution technique. The flow rate was maintained at 1.2 ml/min, and the detection wavelength was 230nm. Results: Aspirin and Dipyridamole were eluted at 4.7min and 12.6min, respectively, using the developed method. The method was linear in the range of 12.5-50μg/ml for Aspirin and 100-400 μg/ml for Dipyridamole, with an r² value of 0.9997 and 0.9999, respectively. The sample recoveries observed were 97.63-100.96% and 97.38-98.01%, respectively, for aspirin and dipyridamole. The forced degradation studies were carried out, and the stressed samples were analyzed using the developed method. The purity angle of the peak was observed lesser than the threshold angle. Conclusion: The method could able to detect the potency of the product using one capsule. The recovery study results confirm the non-interference of formulation additives in the estimation. The purity angle from the forced degradation study confirms the non-interference from degradants in quantitating marketed formulation. Hence, the developed method is precise and accurate.