Polymeric micelle hydrogel of Resina Draconis enables mechanistically targeted protection against skin photoaging

Resina Draconis (RD), a traditional Chinese medicinal resin renowned for its potent antioxidant, anti-inflammatory, and tissue-repairing properties, holds promise for combating skin photoaging. However, its therapeutic translation has been hindered by the poor solubility and limited bioavailability of its principal bioactive constituents. In this study, we developed an RD-loaded polymeric micelle (RDPM) hydrogel to overcome these formulation challenges and evaluated its protective efficacy against UV-induced skin aging. The micellar system, composed of poloxamer surfactants and embedded within a carbomer hydrogel matrix, achieved high encapsulation efficiencies (~ 80-90%) for five representative bioactive constituents (loureirin A, loureirin B, 7,4'-dihydroxyflavone, resveratrol, and pterostilbene). The micellar hydrogel exhibited diffusion-governed release (~ 80% within 24 h), consistent with Higuchi kinetics. In vitro permeation studies confirmed efficient penetration of these actives across the stratum corneum and deposition within the viable epidermis and dermis, the target compartments for anti-photoaging action. In UV-irradiated mice, topical RDPM hydrogel treatment markedly ameliorated wrinkle formation and histopathological alterations, including epidermal hyperplasia, dermal-epidermal junction flattening, collagen loss, and elastotic degeneration. Untargeted metabolomic profiling further showed a treatment-associated normalization of UV-disrupted metabolic networks, consistent with improvement of redox balance, restoration of arginine-NO signaling, and preservation of mitochondrial function. A Draize skin irritation assay classified the formulation as non-irritating. Collectively, this study establishes RDPM hydrogel as a rationally designed topical delivery system that amplifies the pharmacodynamic benefits of RD, offering a mechanistically supported intervention for photoaging within the paradigm of modern Chinese medicinal pharmaceutics.