Development and characterization of a self-double-emulsifying drug delivery system containing both epigallocatechin-3-gallate and α-lipoic acid

The present study investigated a self-double-emulsifying drug delivery system (SDEDDS) loaded with epigallocatechin-3-gallate (EGCG) and α-lipoic acid to improve EGCG photostability and possess a sustained release behavior. The long chain solid lipids (cetostearyl alcohol) and macadamia oil were utilized as a carrier to co-deliver the two bioactive ingredients. The prepared EA-SDEDDS for topical application was formulated using modified two-step method and characterized by confocal microscopy, in vitro release, and antioxidant effects. EA-SDEDDS was found to be stable under simulated sunlight for 1 month (at room temperature). In vitro cell culture studies, EA-SDEDDS provided protection for 3t3 fibroblasts that underwent H 2 O 2 oxidative stress due to sustained release property. Cellular antioxidant activity assay indicated that EA-SDEDDS showed anti-oxidative capacity with the same efficacy compared to EGCG-α-lipoic acid solution.