Evaluation of functional characteristics of preactivated thiolated chitosan as potential therapeutic agent for dry mouth syndrome

Purpose: The objective of this study was to investigate preactivated thiomers for their potential in the treatment of dry mouth syndrome. Methods: Chitosan-thioglycolic-mercaptonicotinamide conjugates (chitosan-TGA-MNA) were synthesized by the oxidative S-S coupling of chitosan-thioglycolic acid (chitosan-TGA) with 6-mercaptonicotinamide (MNA). Test disks were compressed out of unmodified chitosan, chitosan-TGA (thiomers) and chitosan-TGA-MNA conjugates to investigate cohesive properties, cytotoxicity assays and mucoadhesion studies. Results: Immobilizing the MNA achieved higher swelling and cohesive properties of chitosan-TGA-MNA conjugates compared to unmodified chitosan. Rotating cylinder studies displayed a 3.1-fold improvement of mucoadhesiveness of chitosan-TGA-MNA conjugates compared to thiolated polymers. Findings in tensile strength were in good agreement with rotating cylinder ones. Furthermore, preactivated thiomers exhibit higher stability. All conjugates were found non-toxic against Caco-2 cells. Conclusion: Preactivated thiolated chitosan could be a promising system for the treatment of dry mouth syndrome where mucosa requires lubrication and mucoadhesiveness. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.