2.9. In Vitro Drug Release Studies and Kinetics

The in vitro drug release profile of MEM was carried out using a USP dissolving equipment I basket type (Model DS-8000 LabIndia). The capsules were filled with 500 mg of MEM and placed in the dissolving basket containing 0.1 N HCl (500 mL) rotating at a speed of 100 rpm and operating at a temperature of 37.5°C. About 2 mL of aliquots were withdrawn from the dissolving media at different times and replaced with a new buffer solution at regular intervals. The samples were filtered using a 0.45 µm membrane filter, and the amounts of rutin and quercetin were determined using a predeveloped HPLC method. After determining the amount of drug in the filtrate, the percent drug release was calculated [42]. Furthermore, to characterize the release profile, an appropriate model mathematical function was selected and evaluated using the derived model parameters. Different rate kinetic models were used to depict the results of in vitro release studies [43].