Novel stable and high-loaded natural UV filter microemulsion based on optimized emulsifiers system.

A novel oil-in-water (O/W) microemulsion (ME) loading with Ferulic acid (FA) was created, featuring transparent, thermodynamically stable, and forms spontaneously. The formula of FA-loaded microemulsion was optimized based on pseudo-ternary phase diagram, Box Behnken design (BBD) and dissolution test. The optimized formula (2 %FAME) consisted of 1-Decanol (3.98 %, w/w), Cremophor®RH40 (6.72 %, w/w), Tween 80 (0.75 %, w/w), 1,3-Butanediol (29.85 %, w/w), water (56.71, w/w) and FA (2 %, w/w). The microscopic morphology and droplet size distribution were investigated by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The unique emulsion enhanced the solubility of FA in water while demonstrating good stability, controlled release properties, significant free radical scavenging ability and ultraviolet-B (UVB) absorption capacity. Sunscreen properties were demonstrated by Carbomer®934 gel. The sunscreen gel exhibited sun protection properties, while the FA microemulsion demonstrated synergistic effect with ZnO, resulting in a significant enhancement of SPF. These results demonstrate that this novel microemulsion system not only improves the bioavailability of FA, but also provides valuable insights into the development and application of natural UV filters. [Display omitted] • The microemulsion was prepared using a new system of long and short chain alcohols. • The formula was optimized by RSM and phase diagram. • The load, stability, ABTS·+, in vitro release and sunscreen gel of microemulsion were studied. [ABSTRACT FROM AUTHOR]