Naringin nano-ethosomal novel sunscreen creams: Development and performance evaluation

Long term exposure of skin to UV rays produces detrimental effects such as premature skin-ageing and skin cancer. Although, zinc oxide (ZnO) and titanium dioxide (TiO₂) are good sunscreen agents, they do not provide highly efficient UV radiation protection and antioxidant and anti-aging effects. The present study was aimed at developing and characterizing ethosomes loaded with naringin and then to incorporate them into sunscreen creams containing nano-ZnO and -TiO₂ to achieve adequate skin penetration and skin retention so as to scavenge the free radicals by virtue of naringin's antioxidant property. Ethosomes were prepared and optimized with respect to concentrations of ethanol and cholesterol, time of sonication, drug and lipid ratio and amount of drug. The ethosomes were evaluated for size, zeta potential (ZP), polydispersity index (PDI), encapsulation efficiency and surface morphology. Ethosomal sunscreen creams were evaluated for physicochemical tests, spreadability, antioxidant, cytotoxicity and skin permeation studies. Optimized ethosomal formulation exhibited average vesicle size, PDI, ZP and drug encapsulation efficiency of 142.5 ± 5.6 nm, 0.199 ± 0.007, -72.5 ± 2.9 mV and 33.79 ± 1.35%, respectively. Naringin ethosomes showed enhanced retention in the skin (403.44 ± 15.33 μg/cm²) compared to naringin suspension (202.81 ± 9.45 μg/cm²). The optimized sunscreen cream exhibited SPF of 21.21 ± 0.62 with negligible permeation of naringin across the skin. Ethosomes showed pronounced skin permeation for naringin and optimized cream containing naringin ethosomes along with nano- ZnO and TiO2 showed good skin retention for naringin.