Influence of sodium alginate on the properties of methylcellulose-based thermo-sensitive hydrogels

Sodium alginate was added into a methylcellulose-polyethylene glycol-sodium citrate ternary reverse thermo-sensitive system to improve the gel characteristics.The gelation dynamics for various formulations and different pHs were monitored using the viscosity approach to study the influence of sodium alginate on the gel strength.Three low molecular weight drugs were selected to investigate the in vitro release kinetics.The results indicate that the presence of sodium alginate accelerates the gelation process,enhances the gel strength and,thus,improves the gel stability.The quadruple system exhibits a relatively rapid gelling rate together with excellent gel strength at the physiological pH.The new system has excellent controlled release properties for the model drugs.