Objective: The study describes the development of chitosan-based (AMPS-co-AA) semi-IPN
hydrogels using free radical polymerization technique.
Methods: The resulting hydrogels were characterized using Fourier Transform Infrared Spectroscopy
(FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), X-Ray diffraction
(XRD), and Scanning Electron Microscopy (SEM). The successful crosslinking of chitosan, 2-
Acrylamido-2-Methylpropane Sulfonic Acid (AMPS), and Acrylic Acid (AA) was confirmed by FT IR.
Unloaded and drug-loaded hydrogels exhibited higher thermal stability after crosslinking compared to
the individual components. XRD confirmed the decrease in crystallinity after hydrogel formation and
molecular dispersion of Oxaliplatin (OXP) in the polymeric network. SEM showed rough, vague and
nebulous surface resulting from crosslinking and loading of OXP.
Results: The experimental results revealed that swelling and drug release were influenced by the pH of
the medium being low at acidic pH and higher at basic pH. Increasing the concentration of chitosan and
AA enhanced the swelling, drug loading and drug release while AMPS was found to act inversely.
Conclusion: It was confirmed that the hydrogels were degraded more by specific enzyme lysozyme as
compared to the non-specific enzyme collagenase. In-vitro cytotoxicity suggested that the unloaded
hydrogels were non-cytotoxic while crude drug and drug-loaded hydrogel exhibited dose-dependent
cytotoxicity against HCT-116 and MCF-7. Results of acute oral toxicity on rabbits demonstrated that
the hydrogels are non-toxic up to 3900 mg/kg after oral administration, as no toxicity or histopathological
changes were observed in comparison to control rabbits. These pH-sensitive hydrogels appear to
provide an ideal basis as a safe carrier for oral drug delivery.