Fabrication of pH-sensitive chitosan/layered double hydroxide (LDH)/Fe3O4 nanocomposite hydrogel beads for controlled release of diclofenac

In this study, nanocomposite hydrogels based on chitosan/magnetic nanoparticles (Fe 3 O 4 NPs) and Mg–Al double-layered hydroxides (LDH) were prepared as pH-sensitive drug delivery systems for loading and controlled release of diclofenac. The effect of using Fe 3 O 4 NPs in nanocomposites was compared with chitosan and chitosan/LDH hydrogel beads. Sodium tripolyphosphate was used as physical crosslinker agent. The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy, vibrating sample magnetometry (VSM), X-ray diffraction patterns, and scanning electron microscope analyses. The drug release and swelling behavior of these hydrogels have been investigated in aqueous solutions at different pH and under applying the external magnetic field (EMF). The results indicate that swelling and drug release of chit/LDH/Fe 3 O 4 nanocomposites were affected by pH and EMF. The maximum equilibrium swelling of the nanocomposites contains 0.05, 0.10, and 0.15 wt% of Fe 3 O 4 NPs at pH value of 1.2 are 634, 594, and 578% and at pH value of 7.4 are 99, 95, and 90% and at pH value of 9.3 are 57, 53, and 51%, respectively. By increasing of the Fe 3 O 4 NPs content in nanocomposites, the rate of diclofenac release was slower than to control samples and so can concluded that drug release has become more targeted. The percent of drug release for chit/LDH/Fe 3 O 4 nanocomposites under EMF value 0.5 T at pH = 1.2 and 7.4 and 9.3 was at the range of 58.3–76.4% and 20.0–25.1 and 18.3–16.2%, respectively.