Development of novel hydrogels by modification of sterculia gum through radiation cross-linking polymerization for use in drug delivery

Abstract

In order to modify the sterculia gum polysaccharide, to develop the hydrogels meant for the drug delivery, we have prepared sterculia gum, 2-hydroxyethylmethacrylate (HEMA) and acrylic acid (AAc) based hydrogels by radiation-induced crosslinking polymerization. Polymeric networks (hydrogels) thus formed were characterized with SEMs, FTIR,TGA and swelling studies which were carried out as a function monomers concentration, radiation dose, amount of sterculia contents in the polymer matrix and nature of the swelling medium. This paper discusses the swelling kinetics of the hydrogels and release dynamics of anti-diarrhea model drug ornidazole from the hydrogels to evaluation of swelling and drug release mechanism. Diffusion exponent ‘n’ have 0.73, 0.56 and 0.61 values and gel characteristic constant ‘k’ have 1.28×10−2, 2.95×10−2 and 2.14×10−2 values in distilled water, pH 2.2 buffer and pH 7.4 buffer. The release of drug from the polymer matrix occurred through non-Fickian diffusion mechanism. The values for the late time diffusion coefficients have been lower than the values of initial and average diffusion coefficients. It reflects that in the initial stages rate of release of drug from polymer matrix was higher as compared to the late stages, it means after certain time the drug release occurred in controlled manner.