Modification of alginate beads using gelatinized and ungelatinized arrowroot (Tacca leontopetaloides L. Kuntze) starch for drug delivery

Abstract

Arrowroot (Tacca leontopetaloides L. Kuntze) starch in gelatinized and ungelatinized forms was used to modify the characteristics of calcium alginate (CA) beads containing diclofenac sodium (DS). Sodium alginate (SA) was able to molecularly interact with ungelatinized starch (UGS) granules and gelatinized starch (GS) gel via hydrogen bonding mechanisms in the dispersions, leading to viscosity synergism before cross-linking. The GS-CA beads provided a significantly higher DS entrapment efficiency than the UGS-CA beads. The added UGS retarded the water uptake of the CA beads, resulting in slower DS release profiles in purified water and a longer lag time of DS release in pH 6.8 phosphate buffer. On the other hand, GS enhanced water uptake and accelerated the DS release of the beads in both media. Moreover, the 1%GS-CA beads displayed slower DS release than the CA and 1%UGS-CA beads in pH 6.8 phosphate buffer when simulated gastro-intestinal (GI) condition was used. This study shows that UGS and GS obtained from Tacca leontopetaloides L. Kuntze have good potential to improve drug entrapment efficiency of the CA beads, and the DS-loaded GS-CA beads can be used as multiunit dosage forms for sustaining drug release in simulated GI condition.