Dual cross-linking mechanism of sodium alginate composite hydrogel for adhesive microneedle patch preparation

The introduction of microneedles has revolutionized transdermal drug delivery. However, solid microneedle patches often fail to conform to the epidermis and adapt to changes in skin curvature, limiting their effectiveness. Using sodium alginate hydrogel to create flexible microneedle patches can address this issue, but conventional sodium alginate hydrogels suffer from inhomogeneous structure, dehydration, and poor mechanical properties. These drawbacks result in reduced drug delivery efficacy and insufficient mechanical robustness. To enhance the performance of sodium alginate hydrogels, this study presents a novel sodium alginate composite hydrogel with a dual cross-linking mechanism. The hydrogel, with a gelatin to sodium alginate ratio of 1:1, exhibited optimal surface morphology and mechanical properties suitable for microneedle patch preparation. The resulting microneedle patch demonstrated excellent water adhesion, securely attaching to skin and oral mucosa surfaces. In vitro experiments confirmed the microneedle's ability to puncture and release the drug, dissolving and releasing the drug within 15 minutes. The patch also showed superior piercing and dissolution properties on the mouth palate, highlighting it may serve as a potential delivery location for more efficient microneedle patch drug administration. In the future, this technology will show great potential in expanding the scope of drug administration for transdermal drug delivery and in reducing the work pressure of healthcare professionals.