Intestinal-Target and Glucose-Responsive Smart Hydrogel toward Oral Delivery System of Drug with Improved Insulin Utilization

An intelligent insulin delivery system targeting intestinal absorption and glucose responsiveness can enhance the bioavailability through oral insulin therapy, offering promising diabetes treatment. In this paper, a glucose and pH dual-response polymer hydrogel using carboxymethyl agarose modified with 3-amino-phenylboronic acid and l-valine (CPL) was developed as an insulin delivery carrier, exhibiting excellent biocompatibility and effective insulin encapsulation. The insulin encapsulated in the hydrogel (Ins-CPL) was released in a controlled manner in response to the in vivo stimulation of blood glucose and pH levels with higher levels of intracellular uptake and utilization of insulin in the intestinal environment simultaneously. Notably, the Ins-CPL hydrogel effectively regulated blood sugar in diabetic rats over a long period by simulating endogenous insulin, responding to changes in plasma pH and glucose levels, and overcoming the intestinal epithelium barrier. This indicates a significant boost in oral insulin bioavailability and broadens its application prospects.

Fabrication of biodegradable composite microneedles based on calcium sulfate and gelatin for transdermal delivery of insulin

To reduce the inconvenience and pain of subcutaneous needle injection, the calcium sulfate and gelatin biodegradable composite microneedle patches with high aspect-ratio microneedles (MNs) and a flexible substrate have been developed. The microneedles with an aspect-ratio approximate 6:1 exhibit excellent mechanical property which can achieve 0.4N for each needle. The cross-section views show the inside of microneedles that have abundant pores and channels which offer potential for different drug-release profiles. The preparation procedures, degradable property for the biodegradable composite microneedle patches are described in the paper. Insulin, the drug to control blood glucose levels in diabetic patients, has been embedded into the biodegradable composite MNs. The hypoglycemic effect for transdermal delivery of insulin is studied using diabetic Sprague-Dawley (SD) rats as models in vivo. After transdermal administration to the diabetic rats, the released insulin from biodegradable composite MNs exhibit an obvious and effective hypoglycemic effect for longer time compared with that of subcutaneous injection route. This work suggests that biodegradable composite MNs containing of insulin have a potential application in diabetes treatment via transdermal ingestion.