Rapid Transdermal Delivery of Insulin to Diabetic Rats Using Poly-γ-glutamic acid (γ-PGA) Microneedles

• Main Authors: Setiawan JatiKusuma, 古傑翔
• Other Authors: Mei-Chin Chen
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/sr5je6

碩士 === 國立成功大學 === 化學工程學系 === 102 === This study presents a dissolving microneedle system, which is composed of poly--glutamic acid (-PGA) microneedles with a poly(vinyl pyrrolidone)/poly(vinyl alcohol) supporting array, for rapid and efficient transdermal delivery of insulin. The microneedles can be completely dissolved after insertion into the skin for 4 min (and the encapsulated insulin is released rapidly). A histological examination shows that the mechanical strength of microneedles is strong to pierce into porcine cadaver skin to a depth of approximately 400 µm and about 500 µm in rat skin depth. Insulin-loaded microneedles were administered to diabetic rats using a homemade applicator to evaluate the feasibility of using these microneedles for diabetes treatment. Pharmacodynamic and pharmacokinetic results show a similar hypoglycemic effect in rats receiving insulin-loaded microneedles and subcutaneous injection of insulin. The relative pharmacological availability and relative bioavailability of insulin were both 98-99% compared to subcutaneous injection for the two administration, indicating that insulin delivered via γ-PGA microneedles was almost completely absorbed from the skin into systemic circulation. The hypoglycemic effect of insulin-loaded microneedles was almost similar to that of the subcutaneous administration of insulin of the same dose. Storage ability analysis confirms that more than 90% of the insulin remained in the microneedles even after storage at room temperature (25 C) and 37 C for 1 month. These results demonstrate that the proposed γ-PGA microneedles are stable for encapsulating bioactive molecules and have great potential for transdermal delivery of protein drugs in a relatively painless, rapid, and convenient manner.