Although
antibiotic-loaded
bone cement (ALBC) is used as a
drug delivery vehicle to decrease
infection rates, the varied clinical effect of the
antibiotic release remains controversial. The objective of this study is to investigate the enhancement of continuous wave ultrasound (CWU) on
vancomycin release and antimicrobial efficacy of ALBC in vitro and in vivo. We measured
vancomycin concentrations after a 0.5-h exposure of CWU. The results showed that CWU increased the
drug elution by 2.57-27.44% when compared with the controls in vitro. Ultrasonic intensity and
vancomycin load both had a significant effect on the cumulative
drug elution at 10.5 h, with a significant interaction between each other. We also implanted ALBC specimens into hip joints of sixteen New Zealand White female rabbits after inoculations of Staphylococcus aureus around primary implants for 30 days.
Vancomycin concentrations in the hip cavity and urinary elimination of
vancomycin were both measured after intermittent exposures of CWU. The results showed that CWU increased local Tmax by 47.6 microg/mL and urinary elimination of
vancomycin by 109.56 microg, but failed to prolong local T>MIC. On day 30 after the implantation, assessment in clinical performance, radiology, bacteriology, and histology all showed a tendency of decreased bacterial vitality and relieved
inflammation in the infected hip treated by CWU. This study suggested that CWU could effectively enhance
vancomycin release and antimicrobial efficacy of ALBC, which may be of clinical significance for treating
prosthesis-related infections.