Synthesis and characterization of chitosan-homocysteine thiolactone as a mucoadhesive polymer

► Two novel homocysteine thiolactone-chitosan as mucoadhesive polymers. ► Thiolated trimethyl chitosan showed superior pH-dependent mucoadhesive property. ► Both modified chitosan exhibited good swelling behavior but not dissolved at a low pH. ► They might be suitable polymers for drug delivery systems at low pH mucus sites.