Ethylferulate-loaded nanoemulsions as a novel anti-inflammatory approach for topical application

•Ethyl ferulate nanoemulssion improve in vitro release.•Kinetic studies of modified drug release.•Fluorescent-labeled nanoparticles for monitoring intracell drug transport.•Uptake and antinflammatory efficacy studies of ethyl ferulate. Ethyl ferulate (EF) is a phenylpropanoid with antioxidant and anti-inflammatory activities extracted from essential oil of several plants. However, this compound is immiscible with water. In this study, different nanoemulsion (NE) formulations were prepared and have their physicochemical properties assessed to induce a stable and efficient aqueous colloidal dispersion of drug. The oil-in-water NE samples were selected from the pseudo-ternary phase diagram constructed using soybean oil as oily phase, and a mixture of surfactants composed by polysorbate 80 and sorbitan monooleate. The oil phase containing surfactants was mixed with water using a ultrasonication procedure at 25 °C. The formulation with the smallest and uniformly droplet-sized have the ethyl ferulate-loading in three concentrations (1 %, 2.5 %, and 5 % w/w). Their interactions with compounds of NE were followed using Fourier transform infrared spectroscopy. The samples exhibited an incredible physical stability, even after drug-loading. The NE showed the ability for controlling the drug release. The in vivo experiments with rats demonstrated the biocompatibility of tested formulations, no skin irritation signs were identified. In addition, an efficient reducing of paw edema was observed compared to the used control. The experimental achievements suggest an interesting and promising novel ethyl ferulate nanoemulsion, as a potential drug delivery system to be used for topical anti-inflammatory application.