3.8. In-vitro Drug Release Study

Drug release activity of hydrogels was studied using a dissolution medium (900 mL) of 0.1 M HCl (pH 1.2) and 0.2 M phosphate buffer pH (6.8 and 7.4) in USP dissolution apparatus-II (Microtech digital) at 75 rpm and 37 °C. At specific time intervals, 5 mL medium was removed and examined by using UV–Vis spectrophotometer (T80+, Pg instrument, UK) at a λmax 255 nm. To maintain sink condition during the experiment, 5 mL of fresh medium was added [33]. Various kinetic models, including zero order, first order, Higuchi, and Koresemeyer-Peppas models were used to find out the order and mechanism of drug release from the polymeric network. The selection of the best model is based on the closeness of “R2” value to 1.