Spontaneous Emulsification as a Low-Energy Strategy for Designing and Optimizing Resveratrol-Loaded Nanostructured Lipid Carriers

Abstract

Nanostructured lipid carriers (NLCs) have proven to be effective for the delivery of lipophilic drugs by combining high encapsulation capacity with controlled release properties. In this study, NLCs were developed using spontaneous emulsification, a low-energy, simple method that is free of organic solvents. Cetearyl alcohol and Kolliphor RH 40 were employed as the solid lipid and surfactant, respectively. The formulation and process were optimized through a Box–Behnken design, considering mean particle size and size uniformity, as determined by laser diffraction. Colloidal stability was improved by the addition of sodium lauryl sulfate and adjustments to the dispersion polymer. Resveratrol (RVL), used as a model bioactive compound, achieved an encapsulation efficiency of 99%, with a mean particle size of 90 nm, a polydispersity index of 0.2, and a zeta potential of −37 mV, remaining stable for 90 days at 8 °C. Characterization by differential scanning calorimetry/thermogravimetry, Fourier transform infrared, and transmission electron microscopy confirmed the incorporation of the active compound as well as the composition and morphology of the nanocarriers. The system exhibited a delayed and sustained release of RVL, highlighting its potential as a platform for the delivery of bioactive compounds. Overall, the results demonstrate that spontaneous emulsification is a viable and sustainable alternative to the high-energy methods predominantly reported in the literature, enabling the production of stable and efficient NLCs for pharmaceutical and cosmetic applications.