Elution of ciprofloxacin from acrylic bone cement and fibrin clot: an in vitro study

The purpose of this study was to investigate the release of ciprofloxacin from acrylic bone cement and fibrin clot. Under sterile conditions, bone cement and fibrin clot were individually mixed with ciprofloxacin. Ten specimens of each complex were placed in 1 ml of nutrient broth and incubated at 37 degrees C. The nutrient broth was changed daily, and the removed samples were stored at -70 degrees C until the antibiotic concentration in each sample was determined by a microbiological method. The maximum level in bone cement specimens was obtained at the second day (80.80 microg/ml) and its diffusion was rapid at first, decreasing gradually over a period of 365 days. Fibrin clot biodegradable specimens released high concentrations of ciprofloxacin (1.52-49.91 microg/ml) in vitro for the period of time needed to treat bone infections (i.e. 65 days). We conclude that the high release of ciprofloxacin in vitro from acrylic bone cement and fibrin clot is very promising since the obtained levels are much higher than the required minimal inhibitory concentration (MIC) against the implicated pathogens in soft tissue and bone infections. The in vivo relevance of the obtained results requires carefully performed studies in animal models.