Preparation and characterization of guar gum hydrogels as carrier materials for controlled protein drug delivery.

Hydrogels were prepared from guar gum (GG) via esterification with 1,2,3,4-butanetetracarboxylic dianhydride (BTCA). Detailed spectroscopic analysis using FTIR and solid-state NMR revealed that an increase in the BTCA feed amount in the preparation mixture led to an increased degree of crosslinking, which affected the swelling behavior and rheological properties of the hydrogels. The hydrogels exhibited enzyme degradability, and after incubation with ß-mannanase and α-galactosidase, 30-57% of the hydrogels were degraded. In addition, the hydrogels adsorbed bovine serum albumin and hen egg white lysozyme thorough electrostatic and hydrophobic interactions. The protein-adsorbed GG hydrogels exhibited a slow and steady release of the proteins over a 24h period in buffer solutions after a fast release of proteins in the first hour. As such, GG hydrogels are expected to be efficient drug delivery carriers for protein-based drugs.