Characterization and Equilibrium Study of Drug Release of pH-Responsive Chitosan-graft-Maleic Film

Abstract

    This paper reports on a pH responsive material and a mathematical model for a drug release study. This material can be applied as a tumor drug carrier, because the tumor tissue has a different pH (5.7–7.8) compared to the healthy tissue (7.3–7.4). Maleic anhydride (MA) is introduced into the chitosan (CTS) backbone to create a polyampholyte chitosan-graft-maleic (CgM) film that has a pH responsive property. The success of the reaction is confirmed by Fourier transform infrared spectroscopy, which shows a new peak at 1705cm-1. The acidic content and mechanical strength of the material increase with the MA:CTS ratio. Our result shows that the pH responsive property of this material appears at a ratio of 4:2 (weight MA/weight CTS). The equilibrium swelling ratio provides information regarding the isoelectric point, which is obtained at pH 6. The drug release study involves adsorption isotherms and moving boundaries cases. Our calculation results show that the De value varies from 2.71 × 10-7 to 6.37 × 10-7 cm2/min. The Henry constants vary by approximately 102 to 103 in the order of magnitude. The Langmuir maximum adsorption capacity is approximately 100 to 102 mmol/g in the order of magnitude.

Keywords

• adsorption isotherm
• chitosan-graft-maleic
• mathematical model
• moving boundary
• ph-responsive