Practicality of non-invasive glucagon-loaded dissolving microneedle for life-saving treatment of severe hypoglycemia in a diabetic rat model

The development of dissolving microneedles (DMNs) has brought light to the transdermal delivery of biomolecules that are released into the skin through the rapid dissolution of the matrix material to enter the systemic circulation and exert therapeutic effects. Herein, we aimed to prepare, characterize, and analyze the effectiveness of a glucagon-loaded DMN system that rapidly increases blood sugar levels in rats with diabetic hypoglycemia. The stability and content of biological drugs following DMNs preparation was assessed using circular dichroism and bicinchoninic acid kit for protein determination kits(BCA kits). The maximum drug loading capacity of DMNs was approximately 140 μg in each patch, and the microneedles could be stored for up to 14 days under dry storage conditions. In vitro skin permeation studies were conducted using a Franz diffusion cell apparatus for glucagon-loaded DMNs. To investigate the efficacy of transdermal drug delivery, drug-laden DMNs were administered to rats with hypoglycemic diabetes. Compared to subcutaneous injections, microneedle drug release demonstrated comparable efficacy in raising blood glucose levels in vivo. Therefore, this study demonstrated that glucagon-loaded DMNs may be a promising approach for efficient transdermal drug delivery as an alternative to subcutaneous injection for the treatment of severe hypoglycemia in patients with diabetes.