| Objective The effects of the drug concentration, release period, the residue concentration, and releasing time that under the minimal inhibitory concentration from polymethyl methacrylate (PMMA) cement will be studied, in order to lay down a theoretical basis for rational use of antibacterial drugs. Method Imipenem or vancomycin loaded in the PMMA cement samples was eluted in vitro. High performance liquid chromatography (HPLC) was used to quantitatively determine the releasing profile and residue of imipenem or vancomycin in the antibiotic-loaded PMMA samples. Results ① Antibiotics rapidly released from the PMMA samples on the first day, and slowly released at a low concentration afterwards. ② Only 15% of vancomycin and 25% of imipenem were separately released from the antibiotic-loaded PMMA samples after elution for seven weeks. Therefore, there were a large amount of antibiotics remained in the PMMA. ③ The drug releasing concentration from vancomycin-loaded PMMA was lower than the minimal inhibitory concentration after one week, while that from imipenem-loaded PMMA was lower than the minimal inhibitory concentration after seven weeks. Conclusion The drug releasing concentration from antibiotic-loaded PMMA samples was lower than the minimum bacteriostatic concentration, due to a large amount of residues in the PMMA, which likely results in antibiotics resistance for bacteria. |
