Development and Validation of an HPLC-DAD Method for the Determination of Seven Antioxidants in a Nano-Emulsion: Formulation and Stability Study

Oxidative stress degrades skin collagen and elastin and causes inflammatory reactions that affect mitochondrial DNA leading to aging. In the present study, a potential cosmetic nano-emulsion (o/w) of seven substances (chlorogenic acid, caffeine, rutin, hesperidin, quercetin, alpha-tocopherol and retinol) with antioxidant and anti-aging properties was prepared and analyzed. The lipophilic components were entrapped in the dispersed nanoparticles (jojoba) of the emulsion while the hydrophilic ones dissolved in the aqueous phase (glycerol/water). Suitable excipients were selected using an experimental design methodology with two mixtures and two responses (particle size and zeta potential). The quantitative extraction of chlorogenic acid and caffeine from Crithmum maritimum L. plant and coffee beans (Coffea arabica L.) and their stability were also studied. The analysis of the substances was carried out on an HPLC-DAD, with a phenyl column and gradient elution system (solvent A: water with 0.2% formic acid and B: acetonitrile with 0.2% formic acid). Validation of the method was performed in terms of linearity (r(2) > 0.998), precision and repeatability (%RSD < 2) while the limits of detection (LLODs) and quantification (LLOQs) were also determined. The antioxidants were quantified after being extracted from the substrate (%recovery 96.7-102.5, %RSD < 2).