Development of pH Independent Drug Release System for Dipyridamole

Introduction: Dipyridamole is an Anti-platelet agent exhibits release problems at higher pH of small intestine due to its pH dependent solubility and precipitation followed by interruption of drug release from dosage form. To overcome this extended release formulation was developed by using pH modulating agent (tartaric acid). Objective: Present study was undertaken with a view of the formulations evaluated by performing dissolution testing on developed extended released tablets. Method: development of dissolution method at different time points and USP Apparatus 1 (basket) and 2 (paddle) at rotating speeds of 50 or 100 rpm used to evaluate the release characteristics of the formulations. Furthermore, solubility and in vitro dissolution studies of formulated tablets were performed at pH values of 1.2 and 5.5. Results: In this study we found increasing volume of dissolution medium pH 5.5 phosphate buffers drug precipitation is increased. The developed dissolution method was validated according to ICH guidelines for various parameters such as specificity, accuracy, precision, and stability. The dissolution method was confirmed by determining the dissolution rate of extended released Dipyridamole tablets containing pH modulating agent. The best in vitro dissolution profile was obtained using pH 5.5 phosphate buffer as the dissolution medium (500 ml) stirred at 100 rpm. A comparison of the dissolution profiles in official and developed media showed significant differences based on f1 and f2 values. Conclusion: The developed dissolution test exhibited a higher capacity than the compendia methods in differentiating the release profiles of pH independent extended release tablets. It can be applied during formulation development and quality control analysis of pH independent extended release tablets for evaluation of the effects of pH modifier in dissolution medium and processing parameters.