Background: In this study, central composite design was utilized for the optimization of
genipin cross-linked chitosan/Eudragit®-L 100 interpenetrating hydrogel network films fabricated
through solvent evaporation technique.
Methods: Hydrogel formulations were studied using response surface methodology; regression analysis
and the surface plots were used to evaluate the effect of variables on T50% (the time for 50% of drug
release) and dynamic swelling with optimum formulation selection. Initial burst release of drug was
observed from the formulated hydrogels during the first 2 hours of dissolution at simulated gastric pH
1.2 and then slow release during the next 10 hours in the simulated intestinal fluid at pH 7.4. Different
polymer ratios in formulation showed significant influence on T50% and dynamic swelling of hydrogel.
The highest T50% was observed at 9.89 hour and dynamic swelling at 7.86 h.
Result: It was observed that by changing the polymer ratio with cross-linker, release rate of metformin
could be modified. Cross-linker also affects drug release rate, i.e. the release rate is decreased with the
increase in its concentration. The physical state of hydrogel was investigated by scanning electron microscope.
Conclusion: It indicated the uniform distribution of drug in hydrogel matrix system. Moreover, the
presence of hydrogen and ionic bonds between polymers and crosslinking agent formed interpenetrating
hydrogel network, likely responsible for increased value of T50%, as confirmed by FTIR. Acute oral
toxicity study was performed to investigate the toxic effect of crosslinking agent and polymer used in