2.6. Hydrolytic degradation

The hydrolytic rate was conducted in deionized water at 37 °C for 20 h. Fresh hydrogel disks were allowed to swell in de-ionized water. After 5 min, swollen gels were separated from the swelling medium and carefully weighed (initial swelling weight) donates (M_o). The samples were re-introduced into the same container and weighed at regular time intervals until the hydrogels were completely degraded (M_t). The degradations (%) are determined according to eqn (3).^20,21 The results were performed in triplicates.