Development and characterization of dibenzalacetone-loaded oleogels as a potential photoprotective agents for sunscreen formulations

Prolonged exposure to ultraviolet radiation induces erythema, accelerates photoaging, and increases the risk of skin cancer. Sunscreens are the primary strategy for preventing UV-induced skin damage; however, the effective topical delivery of photoprotective agents is often limited by formulation challenges. Dibenzalacetone (DBA), a chalcone derivative with broad UVA and UVB absorption, exhibits strong photoprotective potential but is restricted by poor aqueous solubility. This study aimed to develop and optimize DBA-loaded silicon dioxide (SD) oleogels as topical photoprotective systems. Oleogels were prepared using argan oil (AO) or jojoba oil and optimized through a 2³ factorial design. DBA solubility, critical gelation concentration, rheological behavior, drug content, and in vitro sun protection factor (SPF) were evaluated. Further characterization included spreadability, photostability, skin permeation, differential scanning calorimetry, Fourier transform infrared spectroscopy, stability studies, and cytotoxicity assessment on human keratinocytes. DBA demonstrated high solubility in both oils, enabling the formation of stable, translucent oleogels at a structuring agent concentration of 10%. All formulations exhibited non-Newtonian, pseudoplastic, and thixotropic behavior, acceptable drug content, and broad-spectrum UV protection (λc > 370 nm). AO-based oleogels showed superior SPF values. Formulation F8 (AO, 15% SD, 8% DBA) achieved the highest SPF, excellent spreadability, enhanced photostability, low skin permeation, and no cytotoxicity up to 400 µg/mg.