Optimization of Swelling, Drug Loading and Release from Natural Polymer Hydrogels

Abstract

The current work deals with synthesis of natural polymer hydrogels (Sodium alginate-Chitosan- Arabic Gum) as beads. The beads are formulated with different polymer proportions depending on the experimental central composite (design) Response Surface Methodology (RSM) has been used. The degree of swelling in acidic and neutral mediums was investigated, analyzed, modeled and optimized statistically. A typical drug (Allopurinol) was loaded by using optimized polymer formulations. The loading capacity and the in vitro release profiles were estimated. The shape and morphological analysis for the beads before and after drug releasing have been investigated also by using Scanning Electron Microscope. The results obtained confirmed that Arabic Gum content was a significant parameter in the swelling processes regardless the pH of the swelling media. Thus, swelling indices of the beads were higher in acidic medium (pH 3.9) compared to that once in (pH 7.1), to indicate a pH-sensitive swelling behavior. An optimum RSM results for swelling indices of 504.98 % and 207.97 % were obtained in acidic and neutral medium respectively. The in vitro drug release showed equilibrium after 12 hours where as (66.1- 85.7 %) and (44-54 %) was released at pH 3.9 and 7.1 respectively. The SEM analysis of the polymer beads confirmed that the beads had lost their shape due to erosion and swelling activities after releasing of the drug.