Chrysin is a bioactive flavonoid found in pollens, passion flowers, honey, royal jelly, and propolis, which is commonly used as an ingredient in natural food supplements and is primarily responsible for their pharmacological properties. A transparent chrysin-loaded microemulsion (CS-ME) prepared through a ternary phase diagram was evaluated for use as an antihyperalgesic formulation. It was formulated with 40% Labrasol^® (surfactant), 5% isopropyl myristate (oil phase) and 55% water (aqueous phase) and classified as an oil-in-water (O/W) microsized system (74.4 ± 15.8 nm). Its negative Zeta potential (−16.1 ± 1.9 mV) was confirmed by polarized light microscopy and dynamic light scattering analysis. In vitro studies in Franz-type static diffusion cells showed that chrysin release from CS-ME followed zero-order kinetics. Oral administration of CS-ME in mice resulted in a statistically significantly reduction (p < 0.05) in carrageenan-induced mechanical hyperalgesia compared to the control group. Treatment with CS-ME also showed anti-inflammatory activity by significantly decreasing the TNF-α level (p < 0.01) and increasing that of IL-10 (p < 0.05) compared to the control group. These results suggest that the proposed microsystem is a promising vector for the release of chrysin, being able to improve its capacity to modulate inflammatory and nociceptive responses.

The topical application of ferulic acid (FA) is limited by its low solubility and high susceptibility to oxidation. To overcome these limitations, the multicomponent system Cicloferulic^® (CF) was developed by mixing FA, hydroxypropyl β-cyclodextrin (HPβ-CD), and polyvinylpyrrolidone K30 (PVP K30), which demonstrated greater safety and antioxidant efficacy than FA alone. The physicochemical characterization of FA, CF, and their components showed greater thermal stability and reduced crystallinity of CF, indicating the formation of the system. In cytotoxicity assays on HaCaT cells, FA maintained cell viability only up to 500 µg/mL, while CF maintained viability even at 10.000 µg/mL, demonstrating 20 times greater safety than FA. In cellular antioxidant activity assays, FA and CF showed similar effects at low concentrations. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method, CF and FA reduced more than 70% of DPPH; however, CF contains only 12% FA, indicating an eightfold greater efficiency than FA. Formulations containing FA and CF increased the Sun Protection Factor (SPF) in vitro, even with a 50% reduction in UV filters. However, they did not stabilize formulations with intrinsically photolabile UV filters. In release studies, FA exhibited rapid flow, while CF promoted a modified release profile. Thus, CF stands out as an innovative, multifunctional system that can improve the stability, safety, and efficacy of FA for topical applications.