Design and Evaluation of Gastroretentive Multiple Units of Dipyridamole: in-vitro and in-vivo human studies

Abstract

Objective: The pH dependent solubility of Dipyridamole was made to select as a model drug for the formulation of gastroretentive drug delivery system. Dipyridamole is highly soluble in acidic pH and as the pH increases the solubility of the drug decreases. The study was planned to formulate, characterize with in-vitro and in-vivo evaluation in human volunteers.
 Method: In this study floating mini matrix tablets of Dipyridamole was formulated using HPMC grade polymers by wet granulation method and prepared multiple units equivalent to one dose were filled in one 000 size empty gelatin capsule. The prepared multiple units were subjected to physical evaluation, in-vitro drug release, and stability studies as per ICH guidelines. The in-vivo radiographic studies were conducted for determining the residence time of dosage form in human subjects.
 Results: All the prepared batches showed good physical properties and in-vitro buoyancy. The optimized FD7 formulation remained buoyant for more than 12 h with drug release of more than 90% in 12 h. The drug release kinetics for optimized formulation FD7 followed a first order kinetics with non fickian mechanism. Formulation FD7 was selected as the best formulation based on the in-vitro characteristics and subjected for stability and in-vivo radiographic studies. These studies revealed that the multiple units were stable during the stability period and remained in the stomach for upto 6 h in human subjects.
 Conclusion: Based on in-vitro characteristics and in-vivo radiographic studies, formulation FD7 was concluded as the best formulation among others. Due to increase in gastric retention time, by choosing floating mini matrix tablets we can improve patient compliance and ensure better disease management.
 Keywords: Dipyridamole, Mini matrix tablets, In-vitro buoyancy, Stability studies Radiographic Studies