Design of Starch Coatings to Control the In Vitro Release of Insulin From Chitosan Hydrogels

• Published in: Starch - Stärke 2025-01
• Main Authors: Wei, Benxi, Yin, Luqian, Shi, Ke, Zou, Jin, Fan, Zhenming, Zhu, Senyong, Xu, Baoguo
• Format: Article
• Language: English
• ISSN: 0038-9056; 1521-379X
• DOI: 10.1002/star.202400099

In this study, hydrogels were prepared with different molecular weights of chitosan, and their insulin‐loading property was characterized. Then starch coatings (starch films prepared by normal maize starch [NMS], potato starch [PoS], and pea starch [PeS] with glycerin content of 2%–5%) were designed to control the in vitro release of insulin‐loaded chitosan hydrogels. This will overcome the drawbacks of oral insulin which will be digested in the stomach and show burst release in the small intestine. Results revealed that the water‐blocking properties of the starch films were strengthened with the increase of glycerol contents as plasticizer made the films more compressed and uniform. After coating with NMS, PoS, and PeS films (4% glycerol, w/v), the insulin release of insulin‐loaded hydrogels (prepared by the medium molecular weight of chitosan) was 40.9%, 12.1%, and 9.4% in simulated gastric fluid (pH 2, 2 h), respectively. Afterward, the cumulative insulin release of the above gastric digested hydrogels coated with NMS, PoS, and PeS films reached 66.5%, 87.4%, and 33.0%, respectively, after incubation in simulated intestinal fluid (pH 6.8) for another 22 h. Therefore, PoS film coating showed the best advantage in protecting insulin‐loaded hydrogel from the destruction of acid in the stomach and exhibited a controlled release process in the intestine.