Synthesis and characterization of a chitosan-N-acetyl cysteine conjugate
| Autor: | Vjera Grabovac, Martin H. Hoffer, Andreas Bernkop-Schnürch, Thomas F. Palmberger, Thierry Schmitz |
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| Rok vydání: | 2008 |
| Předmět: |
Swine
Pharmaceutical Science Chitosan chemistry.chemical_compound Intestinal mucosa Tensile Strength Polymer chemistry Mucoadhesion Animals Sulfhydryl Compounds Intestinal Mucosa Carbodiimide chemistry.chemical_classification Molecular Structure Viscosity Chemistry Thiomer Water Hydrogen-Ion Concentration Acetylcysteine Thiol Muramidase Adsorption Rheology Oxidation-Reduction Cysteine Conjugate |
| Zdroj: | International Journal of Pharmaceutics. 347:79-85 |
| ISSN: | 0378-5173 |
| Popis: | The aim of the present study was to synthesize and characterize a novel thiolated polymer by covalent attachment of N-acetyl cysteine to chitosan. The obtained conjugate was characterized in vitro by quantification of immobilized thiol groups and their pH dependent oxidation, swelling behaviour in artificial intestinal fluid at pH 6.8, rheological properties and evaluation of its mucoadhesive properties on freshly excised porcine mucosa. The chitosan-N-acetyl cysteine conjugate was synthesized via a carbodiimide mediated coupling reaction displaying up to 325.5+/-41.8 micromol of immobilized thiol groups per gram polymer. 79% of the total amount of thiol groups was oxidized to disulfide groups during the coupling reaction. Adhesion studies on the mucosa indicate that the resulting polymer shows a 50-fold longer residence time on the mucosa and 8.3-fold higher total work of adhesion necessary to detach a flat-faced polymeric tablet from the mucosa in comparison to unmodified chitosan. Swelling properties at pH 6.8 were rather limited displaying only 5% of increment in weight after 2h of experiment. Within 1h the viscosity of an aqueous chitosan-N-acetyl cysteine conjugate mixture at 37 degrees C, pH 5.0 decreased by 35% after addition of hen white egg lysozyme demonstrating its biodegradability. Because of these features chitosan-N-acetyl cysteine seems to represent a promising novel tool, which might be useful in particular for the development of mucoadhesive and biodegradable formulations. |
| Databáze: | OpenAIRE |
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