Abstract

The aim of present investigation was to develop and optimize sustained release interpenetrating network (IPN) beads of delonix regia seed polysaccharide (DRG) and sodium alginate using response surface methodology. Diclofenac sodium (DS) was chosen as model drug. A central composite design was used to study and optimize the effect of independent variables (A: sodium alginate:DRG ratio and B: calcium chloride concentration) on drug encapsulation efficiency (DEE, %) and drug release in 8h (R8h, %). Total thirteen batches of DRG-alginate IPN beads were prepared by ionotropic gelation method using calcium chloride as a cross-linking agent. The DEE (%) of the beads was found in the range 32.79-56.54%. Swelling of beads was high in phosphate buffer (pH 6.8) whereas, less in 0.1 N HCl (pH 1.2). The beads exhibited sustained release of DS for 8h (65.6±0.98 - 99.9±1.87%) and followed Higuchi model demonstrating non-fickian diffusion mechanism. The observed responses of the optimized batch were similar to the predicted values determined by Design Expert (V.7.0, Stat-Ease Inc, USA) software. The optimized DRG-alginate IPN beads may show good encapsulation of water soluble drugs followed by their sustained release for 8h which might be advantageous in terms of advanced patient compliance with reduced dosing interval.

Key words: Delonix regia gum, Alginate, Beads, Central composite design, Optimization