Preparation of TPM–NCs–gel and its effect on subcutaneous abscess caused by Staphylococcus aureus

The insoluble compound 1,1′-(2,4,6-trihydroxy-1,3-phenylene)bis(3-methylbutan-1-one) (TPM) is used in preparing a TPM nanocrystals gel (TPM–NCs–gel), and its in vitro antibacterial activity and therapeutic effect on subcutaneous abscesses caused by Staphylococcus aureus were evaluated. The effect of a prescription technology on the particle size of a TPM–NCs suspension was investigated using a single factor, and the TPM–NCs prescription was optimized using a Box–Behnken design. A TPM–NCs–gel was prepared using hydroxyethyl cellulose–HHX (HEC–HHX) as a gel matrix and characterized. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of TPM–NCs–gel were determined with the microdilution method. The susceptibility of Staphylococcus aureus to mupirocin ointment, TPM–NCs–gel, and TPM–gel was evaluated by the disk diffusion method. The efficacy of the TPM–NCs–gel for subcutaneous abscess caused by Staphylococcus aureus was evaluated using a mouse model. The optimized TPM–NCs prescription consisted of Tween 80 and TPGS (2.47%), TPM (1.24%) and mannitol (2.32%). The size of the TPM–NCs was 98.2 ​± ​3.9 ​nm, and the polydispersion coefficient (PDI) was 0.235 ​± ​0.023. The particle size and PDI of the TPM–NCs–gel were 112.4 ​± ​7.3 ​nm and 0.148 ​± ​0.068, respectively. The MIC and MBC were both 2.98 ​μg/mL. After 12 days of administration, the bacteria in the abscess site of 2% TPM–NCs–gel experimental group were cleared, the inflammatory cells were reduced, and the skin structure was remodeled. After TPM was prepared into TPM–NCs–gel, the antibacterial activity was enhanced, Staphylococcus aureus at the site of abscess was effectively removed, and wound healing was promoted.