Biocompatible zein-gum Arabic nanoparticles for astaxanthin encapsulation and topical delivery: Preparation and characterization

Astaxanthin (AST), a potent antioxidant, holds great promise for skin health and cosmetic applications but is limited by poor water solubility and stability. This study presents the development of zein nanoparticles modified with gum arabic (GA) for the encapsulation of AST, serving as a topical nanocarrier for AST to enhance its dermal bioavailability and topical delivery. The optimized zein-GA-AST nanoparticles (Z-GA-AST) exhibited a spherical nanostructure with a mean particle size of 199.03 ± 4.63 nm (PDI <0.2) and achieved a high encapsulation efficiency of 90.34 ± 1.74 %. FT-IR spectroscopy analysis confirmed the successful encapsulation of AST within the nanoparticles. The AST-loaded nanoparticles exhibited significantly superior antioxidant activity compared to free AST. At an equivalent astaxanthin concentration of 10 μg/mL, the ABTS and DPPH radical scavenging efficiencies of the nanoparticles were at least 153 % and 128 % higher than those of free AST, respectively. The incorporation of GA enhanced the physicochemical stability and astaxanthin retention of the nanoparticles under various conditions, including different salt ion concentrations, temperatures, and storage durations, by facilitating the formation of a more compact nanostructure. The skin permeation behavior of the nanoparticles was evaluated using Franz diffusion cells and porcine skin. The results demonstrated that Z-GA2-AST1 exhibited significantly higher skin retention (48.37 %) and lower astaxanthin permeation (10.20 %) compared to free astaxanthin. This study provides valuable insights into the preparation and characterization of biocompatible nanoparticles for AST encapsulation, could become a potential formulation for topical delivery applications in cosmetics and topical drug delivery systems.