Swelling and Degradation in Aqueous Solutions of Hydrogels Based on Chitosan and Pectin and on Their Modifications

The swelling and degradation of physical and chemical hydrogels based on chitosan and pectin and their modifications have been compared. Physical hydrogels were obtained by mixing aqueous solutions of chitosan hydrochloride and pectin in the form of a polyelectrolyte complex. Chemical hydrogels were synthesized via the interaction of N-succinyl chitosan and oxidized pectin in solution, wherein crosslinks were made in the form of a Schiff base. It has been shown that the physical hydrogels are relatively stable in acidic and neutral media, while the chemical hydrogels swell in some cases indefinitely in these media. Both types of hydrogels undergo rapid degradation in an alkaline medium.