title: 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.
  
  
  CONCLUSIONS
  Thus, the promising results encourage further investigations and exploitation of this versatile polysaccharide.
authors: Department of Pharmaceutical Technology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
authors: Flavia
authors: F
authors: Laffleur
authors: Julian
authors: J
authors: Wagner
authors: Arshad
authors: A
authors: Mahmood
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004396:Coloring Agents; D003545:Cysteine / Q000737:chemistry*; D006801:Humans; D006820:Hyaluronic Acid / Q000031:analogs & derivatives* / Q000138:chemical synthesis*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007509:Irritants; D009061:Mouth Mucosa; D012235:Rhodamines; D012995:Solubility; D018502:Streptococcus equi / Q000187:drug effects; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013552:Swine; D014014:Tissue Adhesives / Q000009:adverse effects / Q000138:chemical synthesis*
chemical_list: D001672:Biocompatible Materials; D004396:Coloring Agents; D007509:Irritants; D012235:Rhodamines; D013438:Sulfhydryl Compounds; D014014:Tissue Adhesives; D006820:Hyaluronic Acid; C050829:sulforhodamine 101; D003545:Cysteine