Drug Release of a PH/Temperature Sensitive Core-Shelled Beads from Sodium Alginate and Poly(<i>N</i>-Acryloylglycinate)

Abstract

In this paper, a new pH/temperature sensitive hydrogel bead (HME) with core-shelled structure as a drug delivery system was prepared using N-acryloylglycinate and sodium alginate. In caffeine release studies, the effect of different pH value, temperature and the polymer content were evaluated, respectively. The results showed that 62.2% drug was released from the sensitive beads in pH 2.1 within 300 min, whereas 99.3% drug diffused into the medium in pH 7.4 at 37°C. The significantly higher release was observed at higher temperature than at lower temperature. In addition the release amount of drug was decreased with increasing polymer content. The release behaviors of caffeine suggested a feasibility of the beads as pH/thermo-controlled drug release carrier.