The In Vitro Elution Characteristics of Vancomycin From Calcium Phosphate-Calcium Sulfate Beads

The purpose of this study was to determine the elution characteristics of vancomycin when combined with a calcium phosphate-calcium sulfate mixture to form antibiotic beads in an in vitro environment. The beads were placed in phosphate-buffered saline and kept at 36 degrees C for 6 weeks. Three separate assays were undertaken, after which the phosphate-buffered saline was assayed at 24-hour intervals. Elution of the antibiotic was sustained at a gradual rate for 22 days. The amount of vancomycin assayed nearly equaled the calculated amount of antibiotic per bead measured during bead construction. In conclusion, calcium phosphate-calcium sulfate composite beads, when combined with vancomycin, elute vancomycin in a gradual and sustained fashion for 22 days in vitro. Level of Clinical Evidence: 2 (The Journal of Foot & Ankle Surgery 48(5):540-542, 2009)