Synthesis and study on the properties of polysaccharides modified via the Steglich reaction

Modified polysaccharides are widely used as polymers for medical and biomedical purposes. Among them, the products with a crosslinked macromolecular structure occupy an important place. For instance, using N-derivatives of glutamic acid as a crosslinking agent makes it is possible to obtain non-toxic biodegradable polymer materials. In the current work, the results of study on the polysaccharides modification with N-derivatives of glutamic acid via the Steglich esterification reaction are provided. The factors influencing the efficiency of developed synthetic approach were considered, and the structure and composition of the obtained reaction products were investigated. The reaction was shown to proceed successfully by exploiting both carboxyl groups of N-derivatives of glutamic acid, resulting in the cross-linking of polysaccharide molecules under mild conditions. The study of the properties of the obtained products and the NMR study of their structure and composition showed that two fundamentally different polymers were formed—macromolecules with branched and crosslinked structures. The latter, under certain reaction conditions, formed microhydrogels while dispersing in water. Meanwhile, the branched macromolecules were capable of forming self-stabilized aqueous dispersions. Thus, the article presents the research results on the creation of novel polymers for potential medical applications.