A Hyaluronic Acid-Coated Ethosomal Delivery System for Improving the Topical Delivery of Glycyrrhetinic Acid in Sensitive Skin

Background: Effective topical management of sensitive skin remains challenging because inadequate cutaneous delivery limits the therapeutic performance of many anti-inflammatory agents. Glycyrrhetinic acid (GA) possesses well-recognized anti-inflammatory and barrier-protective activities, yet its clinical potential is constrained by poor aqueous solubility and inefficient skin delivery. This study aimed to develop a hyaluronic acid (HA)-engineered ethosomal system to enhance the local delivery and therapeutic efficacy of GA for sensitive skin. Methods: HA-coated GA-loaded ethosomes (HAGA-ETs) were prepared by electrostatic adsorption of HA onto a cationic ethosomal template. The physicochemical properties, release behavior, storage stability, skin retention, cellular uptake, and biological activities of HAGA-ETs were systematically evaluated using TNF-α/IFN-γ-stimulated HaCaT cells and an SLS-induced 3D reconstructed skin model. Results: HAGA-ETs exhibited a mean particle size of 140.1 nm, encapsulation efficiency exceeding 95%, sustained drug release, and good storage stability. Compared with Free-GA and unmodified ethosomes, HAGA-ETs showed improved cytocompatibility, enhanced skin retention, greater keratinocyte uptake, and stronger anti-inflammatory activity. HA pre-saturation attenuated the enhanced cellular uptake of HAGA-ETs, supporting the involvement of HA receptor-mediated cellular interaction. HAGA-ETs also more effectively restored barrier-related markers, suppressed hyper-reactivity- and allergy-associated mediators, and inhibited the activation of MAPK/NF-κB, JAK1/STAT1, and TRPV1-related signaling pathways in both cellular and 3D skin models. Conclusions: HA surface engineering effectively improved the topical delivery and local therapeutic efficacy of GA by enhancing skin retention and keratinocyte interaction. HAGA-ETs represent a promising nanoplatform for the local management of sensitive skin.