Acidified aqueous dispersion (20 ml) of GG (0.8%, w/v, pH 2) were mixed with 0.5 ml of 25% (w/v) aqueous solution of GA. The increase of the viscosity with the reaction time was accompanied by rheology (spindle CP52, at 36 °C). The system was put to react until the desired viscosity (similar to Hylan G-F 20) was reached (15 days).
The obtained hydrogel was dialyzed initially against water and then against buffer phosphate/NaCl (pH 7.3, 0.2 M/0.15 M) to simulate the physiological conditions and Hylan G-F 20 medium. The hydrogel was denoted hereafter as GuarGel.