Innovative salicylic acid microsponges for sustained drug release

•The microsponges encapsulating salicylic acid were prepared as a drug carrier.•The formulation of microsponges was optimized by response surface methodology.•The sustained release and application performance of microsponges were studied. A novel salicylic acid microsponge was prepared using the quasi-emulsion solvent diffusion method. The yield, encapsulation efficiency, morphology, thermal properties, drug state, in vitro release, and application potential were systematically evaluated. The optimized microsponges demonstrated a yield of 84.92 % and an encapsulation efficiency of 68.69 %. The morphology of the microsponges exhibited a porous spherical structure. Additionally, the interaction between salicylic acid (SA) and ethyl cellulose (EC) enhanced the thermal stability of the microsponges and significantly reduced the crystallinity of SA. These microsponges exhibited excellent sustained release characteristics, enabling drug release for up to 78 h. Finally, combining the SA microsponges with the Carbopol 934 hydrogel system demonstrated favorable viscoelasticity, creep recovery, and stability, providing new insights for its application in dermatological treatments.