Objective To optimize the extraction process of Huashi Zhitong Formula (化湿止痛方) and preparation technology of its gel formulation, elucidate the therapeutic efficacy and mechanism of Huashi Zhitong Gel against gouty arthritis, and provide a candidate formulation and theoretical basis for the development of new topical drugs for gouty arthritis. Methods The total phenolic acid content in Huashi Zhitong Formula was determined by ultraviolet spectrophotometry. The extraction process was optimized through single-factor and orthogonal tests. The gel matrix and excipient ratios were screened based on appearance, viscosity, ductility and stability, and the preparation process was further optimized using Box-Behnken response surface methodology. A rat gouty arthritis model was established, anti-gouty arthritis efficacy of Huashi Zhitong Gel was investigated by detecting joint swelling, skin temperature, pain and expressions of inflammatory factors [interleukin-1β (IL-1β), macrophage inflammatory protein-1α (MIP-1α), superoxide dismutase (SOD), Toll-like receptor 4 (TLR4), matrix metalloproteinase 9 (MMP9)]. Integrated with GEO data, network pharmacology and molecular docking, a “component-effect group” network was constructed to analyze the mechanism of Huashi Zhitong Gel against gouty arthritis, followed by experimental validation. Results The optimal extraction conditions of Huashi Zhitong Formula were determined as 60% ethanol, a solid-to-liquid ratio of 1∶10, extraction at 70 ℃ for 1.5 h (repeated twice). The optimal gel formulation consisted of 1% carbomer 940 and 0.2% poloxamer 188 as the matrix, combined with 7.5% humectant, 1.2% penetration enhancer, 14.7% drug load and 0.07% antioxidant. Pharmacodynamic experiment results demonstrated that Huashi Zhitong Gel significantly alleviated joint swelling and pain in rats with gouty arthritis (P < 0.01, 0.001), reduced the levels of IL-1β, MIP-1α in serum and expressions of TLR4, MMP9 in synovial tissue (P < 0.05, 0.01), and increased the activity of SOD in serum (P < 0.05, 0.01). The mechanism study showed that Huashi Zhitong Gel could play an anti-gouty arthritis role by regulating the targets such as prostaglandin endoperoxide synthase 2 (PTGS2), epidermal growth factor receptor (EGFR), vascular endothelial growth factor A (VEGFA), and the pathways such as cyclic adenosine monophosphate (cAMP), chemokines, and calcium signaling. Immunofluorescence staining and qRT-PCR confirmed that Huashi Zhitong Gel could significantly inhibit the expressions of cyclooxygenase-2 (COX-2), VEGFA and EGFR in synovium of rats with gouty arthritis (P < 0.01). Conclusion The extraction and preparation process of Huashi Zhitong Gel are successfully optimized. Huashi Zhitong Gel has a good anti-gouty arthritis effect, and its mechanism is related to multi target and multi pathway regulation.

Huashi Zhitong Formula  /  gel  /  gouty arthritis  /  chlorogenic acid  /  inflammatory response  /  cyclooxygenase-2  /  vascular endothelial growth factor A  /  epidermal growth factor receptor