Glucose-responsive soluble microneedle prepared with “Gelatin - hydroxyethylcellulose ethoxylate complex coacervate” for the transdermal drug delivery

A glucose-responsive "complex coacervate" based drug delivery system has tremendous potential to improve the quality of life and health. Polyquaternium-10, a cationic cellulose derivative offers a potential solution for creating a soluble, painless microneedle patch capable of responding to glucose levels and loaded with the enzyme glucose oxidase (GOx). The gelatin at pH 7.4 forms complex coacervate with polyquaternium at the ratio of 7:3 respectively. As the pH decreases to the isoelectric point of gelatin, the coacervate disassembles and enhances the release of the payload. Microneedles MNs were fabricated in a pyramid shape, containing complex coacervate improved the mechanical strength of MNs, enhancing penetration capability. The incorporation of GOx into the microneedles enabled glucose-responsive behavior. In vitro experiments with artificial skin demonstrated decreased pH within the buffer medium due to the generation of gluconic acid in the presence of GOx. This pH shift triggered enhanced drug release, especially under hyperglycemic conditions, making the system a valuable tool for regulating transdermal drug delivery. In summary, this innovative glucose-responsive drug delivery system based on complex coacervate of gelatin and polyquaternium combines pH-sensitive drug release, mechanical reinforcement, and real-time glucose monitoring, making it a promising solution for improving transdermal drug delivery.