Novel pH-sensitive polyelectrolyte carboxymethyl Konjac glucomannan-chitosan beads as drug carriers

Novel polyelectrolyte beads based on carboxymethyl Konjac glucomannan (CKGM) and chitosan (CS) were prepared via electrostatic interaction. The main advantage of this system is that all procedures used were performed in aqueous medium. The pH-sensitivity of beads was characterized by fourier transformed infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The swelling characteristics of these hydrogel beads at distinct compositions as a function of pH values were investigated. It was found that the swelling rate of test beads was larger (7.4) in the alkaline medium than in the acid medium (5.2) and at pH 5.3 was the smallest (3.5). Furthermore, for the evaluation of the pH effect on drug release from the beads, we studied bovine blood proteins (BSA) release profiles at pH 1.2, 5.0 and 7.4. The pH-sensitivity of the novel polyelectrolyte complex would make an interesting protein delivery system. (c) 2006 Elsevier B.V. All rights reserved.