Synthesis and Characterization of MNPs Hydrogel with pH-Responsiveness Properties to Release Diclofenac Sodium as a Model Drug

In the present study, the loading and releasing of Diclofenac Sodium (DS) were investigated using a pH-sensitive magnetic nanocomposite hydrogel. The hydrogel was prepared through grafting copolymerization of Acrylic Acid (AA) and acrylamide (AAm) and using ammonium persulfate (APS) as a free radical initiator in the presence of Fe3O4@SiO2@ (3-Aminopropyl) trimethoxysilane (APTMS)@Maleic anhydride (MAN) as a cross-linker. The nanocomposite hydrogel structure (Fe3O4@SiO2@APTMS@MAN) was confirmed as the result of XRD, VSM, FT-IR, SEM, EDS, and TEM spectroscopy techniques. Furthermore, thermal properties were deliberated using TGA and DTG. The effects of different parameters such as pH, time, Fe3O4@SiO2@APTMS@MAN content, and salt solutions on swelling behavior were investigated considering the abovementioned outcomes. The adsorption isotherm was studied at 25 degrees C using Langmuir, Freundlich, and Temkin. The adsorption data were well described by the Langmuir isotherm model. A kinetic study revealed the applicability of pseudo-first-order and pseudo-second-order models for the adsorption of mentioned DS. Moreover, the pH sensitivity of nanocomposite hydrogel and loading/releasing drugs were studied. Examining in vitro drug release in different buffer solutions indicated that the pH of the solution could mainly lead to the DS drug-releasing behavior of hydrogel. However, the cumulative release ratio of DS in pH: 7.4 solutions reached up to 93% within 120 min. Consequently, the investigated nanocomposite hydrogel of this study (Fe3O4@SiO2@APTMS@MAN) can be applied in widespread biomedical applications, particularly for controlled, targeted drug delivery purposes.