2.3. In Vitro Release Study

Using dialysis membrane in vitro release profile of MDZ from MDZ-loaded CS NPs was carried out. To a pretreated dialysis bag, a 5 mL suspension of MDZ-loaded CS NPs (containing drug equivalent to 2 mg) was placed, which was then dipped into pH 7.4 phosphate buffer solution in a 100 mL beaker and magnetically stirred at 100 rpm. At predetermined time intervals, 5 mL of solution was taken out for analysis and was replaced by fresh dissolution media. Using a UV spectrophotometer at 221 nm, the concentration of released drug was determined, and the cumulative percentage drug release was calculated. In each experiment, the analysis was done in triplicate.

The data were fitted to different kinetic models such as zero-order, first-order, Higuchi model, and Korsmeyer–Peppas model to interpret the mechanism and kinetics of drug release [32].