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A Novel Multilayer Natural Coating for Fed-State Gastric Protection

Research output: Contribution to journalArticlepeer-review

Rober Habashy, Mouhamad Khoder, Abdullah Isreb, Mohamed A. Alhnan

Original languageEnglish
Article number283
Pages (from-to)e283
Issue number2
Early online date26 Jan 2022
Accepted/In press8 Jan 2022
E-pub ahead of print26 Jan 2022
PublishedFeb 2022


  • pharmaceutics-14-00283.pdf

    pharmaceutics-14-00283.pdf, 2.98 MB, application/pdf

    Uploaded date:28 Jan 2022

    Version:Final published version

    Licence:CC BY

King's Authors


Several nutraceutical products require gastric protection against the hostile environment in the stomach. Currently marketed synthetic and semi-synthetic coatings suffer from major shortcomings such as poor gastric protection, slow-release response to pH change, and the use of artificial ingredients. The challenge of coating natural products is further exacerbated by the relatively high gastric pH in the fed state. In this work, a novel natural enteric coating is presented as a breakthrough alternative to current solutions. Two coating systems were devised: (i) a triple-layer coating that comprises a wax layer embedded between two alginate-based coatings, and (ii) a double-layer coating, where an overcoat of organic acids (fumaric or citric acid) is applied to an alginate-based coating. The multi-layer architecture did not impact the pH-responsive nature of the coating even when more biologically relevant Krebs bicarbonate buffer of lower buffer capacity was used. Interestingly, the gastric protection barrier of organic acid-based coating remained resistant at elevated gastric pH 2, 3, or 4 for 2 h. This is the first report of using an alginate-based coating to provide gastric protection against fed-state stomach conditions (pH 2−4). Being biodegradable, naturally occurring, and with no limit on daily intake, the reported novel coating provides a superior platform to current coating solutions for pharmaceutical and nutraceutical products.

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