Chemical and biological behaviours of hydrogels based on oxidized carboxymethylcellulose coupled to chitosan

Abstract

Carboxymethylcellulose (CMC) was subjected to partial oxidation reaction by 2,2,6,6-tetramethylpiperidine-1-oxyl in the presence of sodium hypochlorite (NaOCl) and sodium bromide (NaBr). Hydroxylamine and acid–base assay methods were used to quantify the aldehyde and carboxyl groups, respectively. Chitosan (CS) was then coupled to CMC or oxidized CMC (OCMC). The carboxyl groups carried by CMC and the free amines by CS were estimated by potentiometry and conductimetry. Characterization and identification of the obtained materials were made by Fourier transform infrared spectroscopy, Ultraviolet–visible spectroscopy and X-ray fluorescence. The blood compatibility test shows that the haemolysis percentages of films are less than 5%, which indicates their good blood compatibility and their non-haemotoxicity. The anti-inflammatory activity reveals that the materials possess an ability to inhibit the denaturation of proteins. The mucoadhesion tests exhibit a marked increase in adhesion times of CMC/CS and OCMC/CS hydrogels on the intestinal mucosa. Besides, swelling behaviour and biodegradability were established.