Preparation, Characterization, and Drug-Release Behaviors of a pH-Sensitive Composite Hydrogel Bead Based on Guar Gum, Attapulgite, and Sodium Alginate

A novel guar gum-g-poly (acrylic acid)/attapulgite/sodium alginate (GG-g-PAA/APT/SA) composite hydrogel bead with excellent pH sensitivity was prepared via a facile ionic gelation approach and characterized by FTIR and SEM techniques. The effect of APT content on the encapsulation efficiency (EE), swelling ratio, and drug release behaviors of the beads was investigated and the in-vitro release kinetics were also evaluated using diclofenac sodium (DS) as the model drug. The results indicate that the burst release effect of DS drug was eliminated due to the incorporation of APT, and the DS cumulative release was clearly decreased with increasing the APT content.