The Study of Methylene Blue Loading into Chitosan-graft-Maleic Sponges

Abstract

This work succeeded in synthesizing sponges from chitosan-graft-maleic anhydride. Chitosan and maleic anhydride at a certain mass ratio (1:2, 1:1; and 2:1) were reacted in dimethyl sulfoxide (DMSO) at 60? for 24 hours. While the gel formation was carried out in distilled water using a dialysis tube. The removal of DMSO from the gel was carried out by soaking the gel in distilled water for two days. After that, the obtained gel was frozen at -25oC overnight before being lyophilized under a vacuum at -40oC for 24 hours. The dry sponge weight obtained after lyophilization is about 5.61% – 6.77% (dry sponge/wet gel). FTIR and TG/DTA then characterized the sponges. The intensity of the new strong FTIR band appeared in the chitosan-graft-maleic sponge at 1560.13 cm-1, which corresponds to the C=C strain. The results of TG/DTA showed that pure chitosan and sponge chitosan-maleate underwent two stages of degradation, namely evaporation of water and pyrolysis of organic compounds. The shift in the peak rate of degradation in the second stage occurred at 300? for pure chitosan and at 340? for a graft-chitosan-maleate sponge. Both results indicate that the reaction was successful. The drug loading capability was investigated using methylene blue as the drug model. The drug loading kinetics corresponded to a pseudo-first-order model with kf ranging from 0.287 to 0.317 day-1. According to the Freundlich model, the adsorption equilibrium with Kf and 1/n values was 4.923 mg/gram and 2.192, respectively.

Keywords

• chitosan
• drug delivery system
• maleic anhydride
• methylene blue
• sponges