608 Development and assessment of nanoparticle-encapsulated sunscreens

The risk of developing skin cancer from ultraviolet radiation (UVR) can be mitigated with sunscreens. Safety and aesthetic concerns about commercial sunscreens have led to our development a bioadhesive nanoparticle (BNP) sunscreen platform. Building upon prior work encapsulating FDA-approved agents avobenzone octocrylene, we now also encapsulated EU-approved diethylamino hydroxybenzoyl hexyl benzoate (DHHB) octinoxate (OCX) 50% 30% loading, respectively. Nonadhesive nanoparticles (NNPs) are produced initially converted BNPs, which possess an aldehyde-rich corona that bind epidermal amines. To assess bioadhesion, 0.01 mg/cm2 BNPs-DHHB OCX were applied Vitro-Skin underwent continuous stirring in water bath. 100% BNPs retained after 1 hour compared 35-58% NNPs. vitro SPF NNPs-DHHB was 100. Furthermore, photostability testing demonstrated encapsulation maintains DHHB stability UVR exposure. complement BNP sunscreens, vivo studies needed examine their ability prevent UVR-induced mutagenesis, occurs through direct indirect mechanisms. In the pathway, photons absorbed by DNA cause immediate damage including formation key mutagenic photoproduct: cyclobutane pyrimidine dimer (CPD). CPDs result mediated non-DNA chromophores may compromise long exposure ends, forming so-called dark (dCPDs). We explored two methods for quantifying dCPDs murine following single, acute UVA (100kJ) exposure: ELISA immunofluorescent staining. Both peaking ∼30 min provide way efficacy preventing living skin. Evaluating performance over chronic protocols will support characterization optimizing formulation.