The Effect of Molecular Weight of Biodegradable Hydrogel Components on Indomethacin Release from Dextran and Poly(DL)lactic Acid Based Hydrogels

Biodegradable hybrid hydrogels from chemically modified dextran and poly(DL)lactic acid (PDLLA) were prepared by UV photocrosslinking of different molecular weights (MWs) of these precursors. A series biodegradable hybrid hydrogels were obtained by changing the composition ratio of hydrogels and MWs of dextran and PDLLA. These hydrogels were characterized by swelling and in vitro biodegradation-induced morphological structure changes. Indomethacin (IDM) was entrapped in these hydrogels and the release kinetics were investigated in a pH 7.4 phosphate buffer solution. The relationship between hydrogel swelling and biodegradation, IDM release from the network hydrogels and the molecular weights of dextran and PDLLA were studied. It was found that the swelling and biodegradation of these hybrid hydrogels were affected by both the MWs of the polymer component and the composition ratio of the hydrogels. IDM release from the hybrid hydrogel networks depended on the structure and hydrophobicity of the hydrogels; the MW effect on IDM release profiles was smaller than on hydrogel properties.