Dissolving Microneedle Patch Incorporated with Insulin Nanoparticles for The Management of Type-I Diabetes Mellitus: Formulation Development and in Vivo Monitoring

Purpose: The present study aimed to fabricate microneedles (MNs) for transdermal delivery of insulin. Chitosan-conjugated carboxy phenyl boronic acid polymer was synthesized and characterized to load insulin in the form of nanoparticles. Methods: Optimized insulin nanoparticles (ILN-NPs) were loaded into MN arrays by micromolding, and the resulting MN patches were characterized by scanning electron microscopy (SEM) and mechanical failure tests. The MNs were evaluated for skin insertion via a confocal laser scanning microscope. The in vivo efficacy (blood glucose levels [BGLs] and serum insulin concentration) of the MNs was studied in diabetic rats in comparison with traditional subcutaneous insulin injection. Results: In diabetic rats treated with MNs incorporated with insulin-loaded nanoparticles (ILN-MNs), the BGLs reached ≤ 200 mg/dL at 2 h following the application of the ILN-MNs and maintained BGLs ≤ 200 mg/dL from 2-8 h. The BGLs decreased to 29 mg/dL at 2 h following the subcutaneous administration of insulin. After 6 h, the BGLs rose to their initial level. These results were supported by the corresponding serum insulin concentrations. Conclusion: The findings of this study demonstrate the reliability of the developed ILN-MNs for sustaining normal BGLs in diabetic rats. Therefore, it can be further explored as an approach for diabetes treatment to improve patient outcomes and quality of life.