Polymer microneedles fabricated from alginate and hyaluronate for transdermal delivery of insulin

To reduce the inconvenient and painful of subcutaneous needle injection, the polymer microneedle patches that fabricated from modified alginate and hyaluronate were prepared for transdermal delivery of insulin. The as-prepared microneedles (MNs) exhibited excellent mechanical strength to penetrate the skin and good degradability to release loaded insulin. In vitro skin insertion capability was determined by staining with tissue-marking dye after insertion, and the real-time penetration depth was monitored using optical coherence tomography. Confocal microscopy images revealed that the rhodamine B and fluorescein isothiocyanate-labeled insulin (FITC-insulin) can gradually diffuse from the puncture sites to deeper tissue. In vivo and pharmacodynamic studies were then conducted to estimate the feasibility of the administration of insulin-loaded microneedle patches on diabetic mice for glucose regulation. The relative pharmacologic availability (RPA) and relative bioavailability (RBA) of insulin from microneedle patches were 90.5 ± 6.8% and 92.9 ± 7%, respectively. These results suggests the MNs developed in this study have a promising application in diabetes treatment via transdermal delivery.