Elution Profiles of Synthetic CaSO4 Hemihydrate Beads Loaded with Vancomycin and Tobramycin

This clinical study of 50 patients investigates the clinical elution profile of STIMULAN combined with vancomycin and tobramycin in periprosthetic joint infection. The study asked if STIMULAN as an antibiotic carrier can provide local antibiotic concentrations in excess of the MICs of common infecting pathogens and in doing so, if it elevates serum antibiotic concentrations levels. These were investigated by using an assay of antibiotic concentrations in serum and surgical drains in the first 5 postoperative days. Analysis of the local exudate indicated maximum elution concentrations on day one for both vancomycin and tobramycin, at 265µg/ml and 31µg/ml respectively, with values maintained at therapeutic concentrations for each of the 5 postoperative days. Blood serum antibiotic concentrations were below the lower concentration limits of the standard assay (vancomycin < 2 µg/ml, tobramycin < 0.5 µg/ml) for the majority of patients. Detectable serum antibiotic levels were present in 12/50 patients at day 1, and 1/50 patients at day 4. The study demonstrates STIMULAN to be safe and effective providing local therapeutic levels of vancomycin and tobramycin above MIC whilst avoiding system toxicity. The abstract and full paper can be read here.