Synthesis and in vitro mucoadhesion studies of chitosan-thioglycolic acid conjugates

Objective:To synthesize chitosan-thioglycolic acid conjugates with high thiol group contents and evaluate their mucoadhesive properties at different pH values.Methods:The modification of chitosan was achieved via the covalent attachment of thioglycolic acid mediated by a carbodiimide.The optimum reaction conditions were investigated by single factor screening method.The structure was investigated by IR.Gravimetric method,rotating cylinder and self-made apparatus were used to evaluate the swelling behavior,time of adhesion and bioadhesive force of the conjugates at different pH values.Results:The content of thiol group in the conjugates was 969 μmol·g-1.The mucoadhesion of the product was higher than chitosan in the small intestine,and there is no significant difference in the gastric and duodenum.Conclusion:Compared with CS,CS-TGA is a more appropriate adhesive material for jejunum and ileum.