Emulsification-based liposomal formulation of gallic acid and curcumin as potent topical antioxidants

Excessive free radicals in the skin cause oxidative stress, damaging cells and leading to aging, melasma, and inflammation. This study developed a liposome system for co-delivering antioxidants to enhance their efficacy in deeper skin layers. Four phenolic compounds were screened for antioxidant activity using DPPH, nitric oxide scavenging, and lipid peroxidation assays. Gallic acid and curcumin, showing the strongest activity, were selected for liposome encapsulation via an emulsification method, with particle size reduction by probe sonication. High-performance liquid chromatography (HPLC) was used for chemical analysis, and particle morphology was examined with transmission electron microscopy. Studies on skin penetration, retention, and release were conducted. The optimized liposome (LP4) had a small particle size (< 150 nm), an unilamellar structure, and high entrapment efficiency (99% gallic acid and 92% curcumin). LP4 promoted effective skin retention of curcumin with slow penetration, while the release of gallic acid and curcumin from LP4 followed a Higuchi kinetic model and Zero-order kinetic model, respectively. This delivery system demonstrates potential for targeted antioxidant delivery, offering enhanced protection against oxidative damage in the skin.