Development of nanoemulsions based on ferulic acid encapsulated in oleic acid with photoprotective potential

Background: Ferulic acid (4-hydroxy-3-methoxycinnamic acid) is a phenolic compound that exhibits remarkable antioxidant activity. This compound presents certain limitations due to its low solubility in aqueous media, which restricts its application; however, its incorporation into nanoemulsions represents an effective approach to dispersing the active substance in water. The primary objective of this study was to develop a nanoemulsion based on oleic acid and ferulic acid, stabilised with Pluronic® F127, aiming to obtain formulations with photoprotective potential. Methods: The nanoemulsions were prepared using a high-energy method and characterised in terms of particle size, polydispersity index, and zeta potential. Encapsulation efficiency was determined, a thermodynamic stability study was conducted, and the photoprotective potential was evaluated. Results: The most stable nanoemulsions exhibited particle sizes of 246.8 ± 3.6 and 208.5 ± 2.6 nm, zeta potentials of −33.2 ± 0.2 and −33.6 ± 0.5 mV, and polydispersity indices of 0.171 ± 0.01 and 0.113 ± 0.02, respectively. The encapsulation efficiency was 99.94%. The estimated Sun Protection Factor (SPF) values were 2.28, 2.70, and 2.96 for formulations containing 0.2%, 0.3%, and 0.5% ferulic acid, respectively. Conclusions: The obtained nanoemulsions demonstrated photoprotective potential at low concentrations and may be used to supplement SPF in photoprotective cosmetic formulations.