ALBANY, N.Y.—Results from a recent study demonstrated a mono/diglycerides of capric and caprylic acids-containing microemulsion is an efficient and safe system to increase lycopene delivery to the skin and the antioxidant activity in the tissue (J Pharm Sci 2010;99:1346-57). Lycopene was incorporated in two microemulsions containing BRIJ-propylene glycol, but different oil phases: mono/diglycerides of capric and caprylic acids (MG) or triglycerides of the same fatty acids (TG). Microemulsions containing MG and TG were isotropic, fluid and clear, with internal phase diameters of 27 and 52 nm, respectively. Both MG- or TG-containing microemulsions markedly increased lycopene penetration in the stratum corneum (6- and 3.6-fold, respectively) and in viable layers of porcine ear skin compared to a control solution. To assure that lycopene delivered to the skin was active, the antioxidant activity of skin treated with MG-containing microemulsion was determined by CUPRAC assay, and found to be 10-fold higher than untreated skin. The cytotoxicity of MG-containing microemulsion in cultured fibroblasts was similar to propylene glycol (considered safe) and significantly less than of sodium lauryl sulfate (a moderate-to-severe irritant) at 1-50 µg/mL.