Objective To establish an ultrasound-assisted nanonization process for realgar and elucidate the scientific connotation of achieving toxicity reduction and efficacy enhancement within safety thresholds through nanonization. Methods The parameters of zirconium ball water-grinding were optimized using central composite design-response surface methodology (CCD-RSM), and nano-realgar was prepared by combining acid washing with ultrasonic shearing. Four processed products (dry-ground Realgar, traditional water-floating Realgar, SDS-assisted water-floating Realgar and nano-Realgar) were characterized by laser particle size analyzer, scanning electron microscope (SEM), specific surface area and porosity analyzer based on the Brunauer-Emmett-Teller (BET) method, and liquid chromatography-atomic fluorescence spectrometry (LC-AFS). Toxicity was evaluated using a Caenorhabditis elegans model, and efficacy was assessed using a mouse wound model. Results The optimal process parameters of zirconium ball water-grinding were determined as milling for 3.9 h, three cycles of levigation, and the addition of 190 g of zirconia balls (the mass ratio of zirconium balls with diameters of 1, 2, 3, 4 mm is 1∶1∶2∶4); The particle size of Realgar sample can be reduced to 300 nm 30 min of sonication at 250 W. BET analysis showed that nano-realgar had well-developed mesopores. LC-AFS results indicated that, compared with the dry-milled product, all processing methods reduced the As³⁺ content, with nano-Realgar being slightly higher but still below the safety limit. In the C. elegans assay, nano-Realgar exhibited the lowest toxicity (P < 0.001). In the mouse wound model, it achieved the highest healing rate, significantly reducing inflammatory factors and upregulating growth factor expression (P < 0.05). Conclusion The zirconium ball water-grinding combined with ultrasound-assisted nanonization process successfully prepares nano-Realgar, which possesses dual advantages of toxicity reduction and efficacy enhancement within safety thresholds, providing a theoretical basis for upgrading the processing technology of Realgar.

Realgar  /  nanonization  /  zirconium ball water-grinding combined with ultrasound assistance  /  toxicity reduction and efficacy enhancement  /  central composite design-response surface methodology  /  Brunauer-Emmett-Teller (BET)  /  liquid chromatography-atomic fluorescence spectrometry  /  As³⁺  /  inflammatory factor  /  growth factor