In Vitro Photoprotection and Functional Photostability of Sunscreen Lipsticks Containing Inorganic Active Compounds

While investigating the in vitro photoprotective efficacy and photostability of lipstick formulations containing titanium dioxide (TiO2) incorporated into mesoporous silica (SBA-15), researchers used samples with SBA-15; TiO2 (free form); and TiO2 incorporated into SBA-15 as lipstick base. The photoprotective efficacy was characterized in vitro. Lipsticks were irradiated in a Suntest CPS+ chamber to evaluate functional photostability. Lipstick base and SBA-15 alone did not display photoprotective efficacy. The sample containing 10.0% TiO2 incorporated into the mesoporous silica generated greater photostability and sun protection factor (SPF) value compared to the one containing only 10.0% TiO2 (free state). Findings suggested that TiO2 + SBA-15 can be considered a broad-spectrum ingredient for innovative sunscreens, particularly for the photoprotection of the lips.