Chitosan-gold nanoparticles: A trend of skin permeation enhancement effect in animal and human skin model

The skin constitutes a significant challenge to drug absorption. Despite its convenience, the physiological properties of skin create a formidable barrier to drug transport. Therefore, drug formulations designed for skin delivery must overcome these obstacles to achieve therapeutic efficacy. The present study evaluated the effect of gold nanoparticles on animal and human skin models. Chitosan-capped gold nanoparticles (CS-AuNPs) and citrate-stabilized gold nanoparticles (Ci-AuNPs) were synthesized through a chemical transformation approach. CS-AuNPs and Ci-AuNPs exhibit a relatively spherical shape and a nano-sized dimension, with diameters of 62.82 + 4.05 nm and 27.58 + 0.37 nm, respectively. The zeta potential of the CS-AuNPs indicates positivity, measuring +37.50 + 0.10 mV, while the Ci-AuNPs exhibit a negative potential of -17.63 + 0.98 mV. The study on skin permeation in pig skin demonstrated that using CS-AuNPs resulted in a superior enhancement of the permeation of sodium fluorescein (NaFI) compared to Ci-AuNPs. To verify the effectiveness of CS-AuNPs in enhancing skin permeation, excised human skin was employed as the most realistic model available. The findings suggested that CS-AuNPs exhibited a notable enhancement in the permeation of NaFI through excised human skin. Additionally, the confocal laser scanning microscope (CLSM) study revealed that using CS-AuNPs could enhance the accumulation of NaFI in excised human skin. The finding suggests that CS-AuNPs have demonstrated significant potential as a skin permeation enhancer for small polar compounds. Therefore, their efficacy in this regard makes them a promising candidate for further exploration in skin permeation enhancement.