In vitro and ex vivo evaluation of biomaterials' distinctive properties as a result of thiolation.

ABSTRACT

BACKGROUND: Polysaccharide hyaluronic acid (HA) was chemically modified with cysteine ethyl ester (CYS). By immobilization of the thiol-bearing ligand on the polymeric backbone the thiolated bioconjugate HA-CYS was obtained. METHODOLOGY & RESULTS: Mucoadhesion, permeation enhancement effect and stability was tested. Furthermore mechanical, physicochemical properties as well as mucoadhesive strength, swelling index and residence time on the mucosa were investigated. The developed thiolated bioconjugate displayed 1.5-fold improved mucoadhesiveness on buccal mucosa as well as an enhanced permeation behavior and 2.5-fold higher polymer stability. The near neutral pH and 2.49±0.49% cytotoxicity over 12-h studies indicated their non-irritability and biocompatible nature with biological tissues. Further, the model drug sulforhodamine 101 was incorporated to determine its drug release profiles, which revealed a 2.8-fold controlled release of HA-CYS in comparison to unmodified HA. CONCLUSION: Thus, the promising results encourage further investigations and exploitation of this versatile polysaccharide.