Desenvolvimento e caracterização de microemulsão contendo extrato metanólico de Libidibia ferrea (Mart. Ex. Tul.) L.P. Queiroz para o tratamento de feridas crônicas diabéticas

Abstract

Chronic cutaneous lesions, such as diabetic ulcers, represent a significant clinical challenge, characterized by a persistent inflammatory state and a dysregulated immune response that impairs tissue repair. Libidibia ferrea (Jucá), a plant from the Amazonian biodiversity, contains phenolic compounds, such as tannins and flavonoids, with recognized anti-inflammatory and immunomodulatory potential, capable of acting on the pathways that perpetuate the chronicity of these wounds. However, the topical efficacy of these active compounds depends on a delivery system that can overcome the skin barrier and ensure their stability. This work aimed at the development and physicochemical characterization of water-in-oil (W/O) microemulsions for the delivery of the methanolic extract of L. ferrea. The extract was phytochemically characterized by LC-MS, confirming the presence of bioactive compounds. Placebo (MEPLA) and formulations with 10% (ME 10%) and 20% (ME 20%) of the extract were developed. The characterization included pH, conductivity, viscosity, particle size (DLS), and zeta potential analyses. The results demonstrated the formation of W/O systems with nanosized droplets (~255 nm for ME 10%) and a highly negative zeta potential (~ -70 mV), indicative of high electrostatic stability. The ME 10% formulation proved to be the most promising, while the ME 20% showed physical instability. A challenge identified was the final acidic pH of the active formulations (4.11 for ME 10%), indicating the need for optimization to ensure skin compatibility. In conclusion, the ME 10% microemulsion is a promising vehicle for delivering the immunomodulatory compounds of L. ferrea, and this study establishes the essential pharmacotechnical foundation for its future optimization and biological evaluation as a novel therapeutic alternative.