Synergistic Antioxidant Effects and Development of Niosomes Loaded with L-Ascorbic Acid, Alpha-Tocopherol, Ferulic Acid, and Ergothioneine

The development of effective cosmetic formulations containing L-ascorbic acid is hindered by its rapid degradation and poor skin permeation. To address these limitations, this study identified an optimal synergistic antioxidant combination to enhance L-ascorbic acid efficacy and encapsulated it within a niosomes to improve stability and skin retention. Among various ratios evaluated via DPPH assays, a 1:1:2:2 combination of L-ascorbic acid, alpha-tocopherol, ferulic acid, and ergothioneine (Mix D) exhibited the highest synergism. Subsequent FRAP, anti-tyrosinase, and anti-aging inhibition assays confirmed that Mix D contributed to skin-brightening and anti-aging efficacy. Consequently, Mix D was encapsulated into niosomes (NI3-3A), initially showing a vesicle size of 130.67 nm and a PDI of 0.11, and an entrapment efficiency of 70.63%. NI3-3A provided exceptional chemical protection, limiting L-ascorbic acid degradation to 25.06% and maintaining an entrapment efficiency of 63.93% over 90 days due to its robust bilayer structure. Furthermore, it exhibited remarkable physicochemical stability, with a vesicle size of 140.27 nm and PDI of 0.09 after 90 days, while achieving a skin retention of 56.91% significantly higher than the unencapsulated solution (11.32%). In conclusion, this niosomal formulation successfully overcomes the stability limitations of L-ascorbic acid, offering a promising active ingredient for the development of advanced skin-brightening and anti-aging topical products.