Investigation of the Effect of Different Flow-Through Cell Designs on the Release of Diclofenac Sodium SR Tablets

This study was proposed to evaluate the effect of different cell designs and hydrodynamic conditions of the flow-through cell (FTC), USP dissolution Apparatus 4, on the release rate of a sustained-release product. Sustained-release (SR) diclofenac sodium (DS), 100 mg/tablet, was selected for this study. Different cell sizes and types, the flow rate of dissolution medium, and the tablet position within the FTC were considered. Results revealed that some of these variables affect the release rate of DS. It was obvious that the turbulent flow of the dissolution medium resulted in a higher DS release rate compared with the laminar flow. In addition, the results show that the drug release rate decreased when the tablet was buried in the glass beads compared with the unburied tablet. On the other hand, variables such as cell size (12-mm and 22.6-mm diameter), flow rates (8 and 16 mL/min), and presence of a tablet holder had a negligible role in drug release rate