Determination of Gelation Kinetic Parameters for a Chitosan/β-Glycerophosphate Injectable Hydrogel by Means of Rheological Measurement

The aim of the current study was to improve the knowledge of the gelation process of injectable thermosensitive hydrogels comprising chitosan (CS) and β-glycerophosphate disodium salt (β-GP). The sol-gel transition process was precisely tracked by means of rheological measurement, in which the viscosity changed considerably with gelation time and temperature. The zero-order kinetics model was assumed to adequately describe the extent of gelation reaction. The reaction rate constant increased continuously with the increasing temperature and β-GP concentration. According to Arrhenius equation, the activation energies of gelation reaction for the chitosan injectable hydrogels were calculated as 64.38 KJ/mol, 101.68 KJ/mol and 140.92 KJ/mol for the samples containing 4% w/v, 6% w/v and 8% w/v of β-GP, respectively. It could be an effective way to study the gelation dynamics of injectable hydrogels, and provide references for clinical practice.