Chitosan-capped gold nanoparticles and the development of dissolving microneedles loading Chitosan-capped gold nanoparticles for transdermal delivery

Abstract

Drug administration through the skin is widely accounted as a convenient option. This study examined the effect of chitosan-stabilized gold nanoparticles (CS-AuNPs) and citrate ion-stabilized gold nanoparticles (Ci-AuNPs) on the skin permeation of fluorescein sodium salt (NaFI) and fluorescein isothiocyanate-bovine serum albumin (FITC-BSA), as small and large model hydrophilic permeants, respectively. CS-AuNPs and Ci-AuNPs were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS) methods. To examine the skin permeation, studies were conducted on neonatal pig skin using vertical Franz diffusion cells, TEM, and confocal laser scanning microscopy (CLSM). The safety of CS-AuNPs on human skin fibroblast was also assessed using the MTT assay. The nanosized particles of the synthesized CS-AuNPs and Ci-AuNPs were in a spherical shape. The CS-AuNPs had a positive zeta potential, while the Ci-AuNPs had a negative zeta potential. According to the skin permeation study, CS-AuNPs were found to effectively improve the permeation of both NaFI and FITC-BSA. Additionally, CLSM visualization indicated that skin permeation was enhanced by improving the delivery through the transepidermal pathway. The CS-AuNPs were considered safe for human skin cells. The distribution study also found that the particles mainly remained on the upper layers of the skin and did not permeate. Above all, CS-AuNPs show potential as a skin permeation enhancer for hydrophilic compounds in cosmetics and pharmaceuticals. Furthermore, dissolving microneedles (DMNs) incorporated with CS-AuNPs (Au-MNs) were developed to enhance skin delivery. CS-AuNPs at 15%wt were added to the polymer solution to create Au-MNs using microneedle molds. However, our study showed that combining CS-AuNPs with DMNs did not have a synergistic effect to increase skin drug delivery of hydrophilic molecules.

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