Investigation of gelatin/chitosan as potential biodegradable polymer films on swelling behavior and methylene blue release kinetics

The aim of this study was to design genipin-cross-linked gelatin/chitosan films and investigate the swelling behavior of these films and also investigate the release kinetics for methylene blue as a model drug. It was shown that the change in the gelatin ratio did not have much effect on the swelling behavior, but the change in genipin concentration had a significant effect on the swelling behavior of the films. The influence of pH was investigated on the release profiles of Methylene Blue. When the diffusion exponent value of n was calculated, it was observed that the diffusion type in an acidic environment (pH 1.5) changed from anomalous to less Fickian due to the increase in genipin ratio. In basic conditions (pH 8.0), completely anomalous diffusion behavior was observed. As a result of the ninhydrin test, it was revealed that the cross-linking ratio reached up to 65% when 1.5% genipin was used. In the methylene blue model drug release studies, a very controllable release was observed, complying with the zero-order kinetic model at low pH (pH 1.5), except for the 1.5% genipin ratio. At high pH (pH 8.0), only 4.1 percent of the model drug was released. It was also observed that a zero-order kinetic model was seen for all genipin ratios. K-0, the kinetic rate constant of model drug release, was calculated an average 0.025 mg.min(-1)at pH 1.5 and 0.001 mg.min(-1)at pH 8.0, respectively. These values show that release rate at pH 8.0 was significantly lower than at pH 1.5.

Automated summary

The study showed that genipin concentration significantly affects the swelling behavior of genipin-cross-linked gelatin/chitosan films, and pH has a notable influence on the release of methylene blue. The results indicated a cross-linking ratio of up to 65% when using 1.5% genipin, with significantly lower release rate at pH 8.0 compared to pH 1.5.