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Thiolated polymers — thiomers: development and in vitro evaluation of chitosan–thioglycolic acid conjugates

Paper ID Volume ID Publish Year Pages File Format Full-Text
13801 909 2001 8 PDF Available
Title
Thiolated polymers — thiomers: development and in vitro evaluation of chitosan–thioglycolic acid conjugates
Abstract

The aim of this study was to improve mucoadhesive properties of chitosan by the covalent attachment of thiol moieties to this cationic polymer. Mediated by a carbodiimide, thioglycolic acid (TGA) was covalently attached to chitosan. This was achieved by the formation of amide bonds between the primary amino groups of the polymer and the carboxylic acid group of TGA. Dependent on the pH-value and the weight ratio of polymer to TGA during the coupling reaction the resulting thiolated polymers, the so-called thiomers, displayed 6.58, 9.88, 27.44, and 38.23 μmole thiol groups per gram polymer. Tensile studies carried out with these chitosan–TGA conjugates on freshly excised porcine intestinal mucosa demonstrated a 6.3-, 8.6-, 8.9-, and 10.3-fold increase in the total work of adhesion (TWA) compared to the unmodified polymer, respectively. In contrast, the combination of chitosan and free unconjugated TGA showed almost no mucoadhesion. These data were in good correlation with further results obtained by another mucoadhesion test demonstrating a prolonged residence time of thiolated chitosan on porcine mucosa. The swelling behavior of all conjugates was thereby exactly in the same range as for an unmodified polymer pretreated in the same way. Furthermore, it could be shown that chitosan–TGA conjugates are still biodegradable by the glycosidase lysozyme. According to these results, chitosan–TGA conjugates represent a promising tool for the development of mucoadhesive drug delivery systems.

Keywords
Chitosan; Chitosan–thioglycolic acid conjugate; Thiomers; Mucoadhesion; Biodegradability
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Thiolated polymers — thiomers: development and in vitro evaluation of chitosan–thioglycolic acid conjugates
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 22, Issue 17, September 2001, Pages 2345–2352
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us