Microwave assisted synthesis and optimization of Aegle marmelos-g-poly(acrylamide): release kinetics studies

Microwave assisted grafting of poly(acrylamide) on to Aegle marmelos gum was carried out employing 3-factor 3-level full factorial design. Microwave power, microwave exposure time and concentration of gum were selected as independent variable and grafting efficiency was taken as dependent variable. A. marmelos-g-poly(acrylamide) was characterized by FTIR, DSC, X-ray diffraction and scanning electron microscopy. Microwave power, microwave exposure time had synergistic effect on grafting efficiency where as concentration of the gum did not contributed much to grafting efficiency. Batch having microwave power - 80%, microwave exposure time -120 s and concentration of A. marmelos gum - 2% was selected as the optimized formulation. Comparative release behaviour of diclofenac sodium from the matrix tablets of A. marmelos gum and A. marmelos-g-polyacrylamide was evaluated. The results of kinetic studies revealed that the graft copolymer matrix, marketed tablets and polymer matrix tablets of A. marmelos gum released the drug by zero order kinetics and with n value greater than 1, indicating that the mechanism for release as super case II transport i.e. dominated by the erosion and swelling of the polymer.