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Issue 30, 2018
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Pulsatile release from a flat self-oscillating chitosan macrogel

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Coupling oscillatory chemical reactions to smart materials which can respond to external stimuli is considered an answer to the long-standing issue of pulsatile drug delivery. Although a number of coupled architectures exist, there are no systems reporting pH-controlled pulsed drug release based on chemical oscillators. In this paper, we report for the first time a proof-of-concept self-oscillatory chitosan macrogel, employing the palladium-catalysed oxidative carbonylation reaction as the driving force of its oscillations. The reported hydrogel is composed of highly biocompatible components and a novel imine-functionalised chitosan–palladium catalyst with zero leaching rates. This macrogel was shown to rhythmically release not only the products of the reaction, but also fluorescein, which is used as an FDA-approved model drug. The step-wise release pattern corresponded to the step-wise dynamics of pH decrease in methanol:water, while in pure methanol, the changes in pH had an oscillatory mode, accompanied by mirrored oscillations in fluorescein concentration. This proof-of-concept system significantly expands the horizons of pulsatile delivery materials for future research.

Graphical abstract: Pulsatile release from a flat self-oscillating chitosan macrogel

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Publication details

The article was received on 21 Mar 2018, accepted on 14 Jul 2018 and first published on 20 Jul 2018

Article type: Paper
DOI: 10.1039/C8TB00781K
Citation: J. Mater. Chem. B, 2018,6, 5003-5010

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    Pulsatile release from a flat self-oscillating chitosan macrogel

    I. Anna and N. Katarina, J. Mater. Chem. B, 2018, 6, 5003
    DOI: 10.1039/C8TB00781K

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