Chitooligosaccharide-based hydrogel microneedle for the effective transdermal delivery of vancomycin

Hydrogel Microneedle Patches (HMNPs) are effective transdermal drug delivery systems designed to provide a minimally invasive and painless transfer of the incorporated payloads across the stratum corneum barrier. Herein, Chitooligosaccharide (COS) based hydrogel microneedles of four different concentrations (15%, 20%, 25% and 30% PEGDA) were developed using Polyethylene Glycol Diacrylate (PEGDA) and Carboxymethyl Chitosan (CMC) as crosslinkers and Vancomycin hydrochloride (COVAN) as the incorporated drug. Several characterization methods, such as Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM), were performed before evaluating their efficacy as a transdermal therapeutic cargo delivery depot through mechanical testing, swelling ratio, drug release performance, and antibacterial activity. All of the tested formulations exhibited adequate compressive strength over 0.2 N per microneedle and effective penetration capabilities across the stratum corneum barrier. The 30% HMNP exhibited the highest swelling at 255% after 24 h, whereas the 25% HMNP provided the highest drug release at 83% after 48 h, indicating a Fickian diffusion-induced drug release mechanism. This was confirmed by fitting drug release data into mass transfer models, where all formulations except the 30% HMNP's drug release data fit the Korsmeyer-Peppas model. Except for the 20% HMNP, all HMNPs exhibited significantly greater antibacterial activity against a gram-positive bacterium, B.cereus, compared to vancomycin alone. Such efficacy establishes the HMNPs as potential transdermal drug delivery systems (TDDS) in the treatment of gram-positive bacteria-induced diseases such as cellulitis, folliculitis, etc.