**4. Conclusion**

Many conclusions can be made from the present work, the ferrogels (FG) are cross-linked polymer networks containing magnetic nanoparticles: a) magnetic magnetite (Fe3O4) were synthesized successfully by chemical co-precipitation and has been confirmed using FT-IR, VSM analysis, TGA. The advantage of the co-precipitation method are low cost, rapidity, ease, reproducibility and high-yield synthesis. b) The hydrogel was formulated by cross-linking chitosan (CS) and oxidized chitosan (OCS) via the Schiff-base (-C=N-) reaction. Obviously, these results indicate that this exhibit non-toxic, biodegradable, good injectability, less expensive and respect the environment, quick gelation time, in vitro pH-dependent equilibrated swelling ratios, interconnected porosity. c) Magneto-responsive hydrogels are typically prepared by incorporating magnetic particles into hydrogels

and has been confirmed using (FT-IR), (TGA), (VSM) analysis at room temperature. d) The role of Fe3O4 embedded in hydrogel, which allows reducing the surface voids and rendering the pore blockage, lower penetration, and thus slowing down the release rate of the drug. e) A 5-Fluorouracil (5-FU), caffeine and ascorbic acid release tests were used to demonstrate the excellent in vitro drug release behavior of these hydrogels and ferrogels. However, all these results indicate that this type of biomaterial based on chitosan with oxidized chitosan in the presence of the three drugs with different solubility for the preparation of hydrogels effective for the controlled release of the drug. Compared to other hydrogels based on chitosan, the present study brings to the attention of researchers a novel strategy to design a non-toxic and biodegradable matrix for drug delivery systems, by the simple use of appropriate oxidized chitosan without incorporating any crosslinking agents. This design expands the variety of hydrogel matrices, guiding additional efforts in the development of the new ideas for pharmaceuticals applications. As a perspective and future challenges, we will test this type of ferrogels for cancer treatment by hyperthermia.
