Synthesis and characterization of a novel inulin hydrogel crosslinked with pyromellitic dianhydride
Barclay, Thomas G
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Smart hydrogels with pH and enzyme triggered release suitable for colon specific drug delivery were prepared by crosslinking inulin with pyromellitic dianhydride (PMDA) in a simple one pot synthesis. Back titration, Fourier transform infrared spectroscopy (FTIR) and ultraviolet spectrophotometry (UV) demonstrated that the hydrogel crosslinking reaction resulted in ester linkages and carboxylic acid groups and that the amount of the crosslinker in the hydrogel increased with increasing PMDA concentration in the crosslinking reaction. Thermal analysis and scanning electron microscopy (SEM) confirmed the chemical change by illustrating the hydrogels changed thermal properties and appearance compared to inulin. This hydrogel showed excellent swelling in water and the degree of swelling was inversely proportional to the cross-linking density, as determined using Flory-Rehner theory. Due to the presence of the carboxylic acid groups in the structure, the swelling was pH dependent, with significantly reduced swelling as acidity decreased from pH 7.4 to pH 1.2.
This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ which permits use, distribution and reproduction in any medium, provided the original work is properly cited. This author accepted manuscript is made available following 24 month embargo from date of publication (November 2018) in accordance with the publisher’s archiving policy.