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UBC Theses and Dissertations

Nanoencapsulation and buccal delivery system to augment bioavailability of insulin Guo, Yigong


Numerous challenges must be overcome to achieve the goal of oral delivery of insulin, such as low gastric pH, proteolysis enzymes in the upper gastrointestinal tract, and insufficient permeation and bioavailability. Although the insulin can be protected by the nanoencapsulation technology, traditional oral delivery followed by gastrointestinal tract absorption of these nano-encapsulated insulin is considered unpredictable due to unstable absorption and slow onset of action compared with injection. Our study prepared triple layer buccal mucoadhesive tablets containing insulin nanoparticles coated with a new material, MNA-TG-chitosan, which is a bioadhesive material with higher buccal delivery efficiency. The chitosan/sodium tripolyphosphate/insulin crosslinked nanoparticles used in tablets were optimized to 318 nm of particle size, 0.18 of PDI, 99.4% of entrapment efficiency, and 25.01% of loading content with ionic gelation method using ultrasonicator. In order to optimize the release profile of insulin along with uni-directional drug release toward the buccal mucosa, triple layer buccal tablets were designed. By optimizing the ratio of the materials used in the bioadhesive layer, the mucoadhesion force of 1.12 ± 0.16 N was achieved and mucoadhesion time can be extended to more than 8 hours. Tablets with the optimized bioadhesive layer exhibited high release rate, which can release more than 90% of the insulin in 2 hours. Furthermore, it can be noticed that all tablets containing the insulin nanoparticles coated with the new material, MNA-TG-chitosan resulted in longer mucoadhesion time and higher release rate compared with tablets containing the insulin nanoparticles coated with pure chitosan and TG-chitosan. In vivo study indicated that the insulin buccal tablets can significantly decrease the blood glucose level with faster onset of hypoglycemic effect compared with the oral administration of free insulin. Compared with intraperitoneal injection administration, although the insulin buccal tablets resulted in slightly slow onset, it had longer duration of blood glucose reduction effect. The biodistribution assay showed that the buccal tablets can deliver insulin with a pattern more likely as the i.p. injection. This result indicated that the buccal tablets containing insulin nanoparticles encapsulated with MNA-TG-chitosan had the similar fast onset of action as injection while can be administrated more conveniently.

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