Rheological investigation of thermoresponsive alginate-methylcellulose gels for epidermal growth factor formulation

Abstract

Epidermal growth factors (EGF) serve as promising candidates for skin regeneration and rejuvenation products, but their instability hinders them from widespread use. Protective immobilization and directed release can be achieved through implementing a hydrogel delivery system. Alginate and methylcellulose are both natural polymers offering biocompatibility and environmental sensitivity. This blended gel system was investigated rheologically to understand its performance in topical applications. Alginate and methylcellulose were found to form a synergistic gel system that resulted in superior viscosity and thermoresponsiveness compared to the individual components. Increasing methylcellulose concentration directly enhanced gel elasticity, and higher viscosities provided better thermal protection of EGF. The addition of EGF at 3.33 mg/mL resulted in a decrease of viscosity but an increase in viscoelastic modulus. EGF concentration also played a large role in shear viscosity and thermoresponsiveness of the ternary system. An alginate-methylcellulose system presents promising rheological tunability, which may provide EGF thermal protection in a topical delivery format.