Biogenic Synthesis and Characterization of pH-sensitive Magnetic PVA/Starch/MnFe₂O₄ Hydrogel for Prolonged Release of 5-Fluorouracil

Dual-stimuli sensitive hybrid Polyvinyl alcohol (PVA)/Starch/Manganese iron oxide (MnFe₂O₄), i.e. PS/pp-MI hydrogel membranes were successfully developed in a non-toxic way. Different hydrogels (PS, PS/pp-MI1, PS/pp-MI2 and PS/pp-MI3) were synthesized by varying the amount of MnFe₂O₄ nanoparticles (pp-MI NPs) in polymer matrix. From TG-DTA, peak decomposition temperatures were found at 211, 210, 216 and 273 ℃ for PS, PS/pp-MI1, PS/pp-MI2 and PS/pp-MI3 hydrogels, respectively, and pp-MI NPs were found to improve the thermal stability of hydrogel. Electron microscopy images display the increase in pore size from 3.3 to 8.6 μm with increase in pp-MI loading in hydrogels. PS/pp-MI1 revealed magnetic behaviour due to incorporation of ferromagnetic pp-MI NPs with the magnetization value of 0.614 emu/g. Also, the water absorption and retention capability of the hydrogels were assessed. Swelling studies revealed high responsiveness of the synthesized hydrogels to pH changes. The 5-Fluorouracil (5-FU) loading of hydrogels with highest encapsulation efficiency of 90% was observed for PS/pp-MI3. In vitro release studies revealed the suitability of hydrogels for sustained 5-FU release with the absence of initial burst release. Korsmeyer-Peppa kinetic model was used to study the drug release mechanisms. Through MTT assay, pp-MI NPs were found to possess significant antitumour activity with the 50% inhibition concentration (IC₅₀) values of 51.26 µg/ml for 24 h and 35.03 µg/ml for 48 h treatments. Whereas, hybrid hydrogels have no tumour-toxicity due to successful entrapment of pp-MI NPs in the hydrogels. All these studies suggest that the novel PS/pp-MI hydrogel is an effective choice for cancer therapeutics.