Local antibiotic delivery with OsteoSet, DBX, and Collagraft

Biodegradable local antibiotic delivery systems have gained interest for prophylaxis and treatment of musculoskeletal infections. We studied the biodegradable materials Osteo- Set, DBX and Collagraft for local delivery of vancomycin and gentamicin in vitro. We determined the antimicrobial activity of vancomycin and gentamicin after mixing with each biodegradable material and determined the release of each antimicrobial from each material in an intermittent flow chamber. Antimicrobial activity was expressed as percent of antimicrobial loaded into each sample that was detected; antimicrobial release was expressed as concentration (microg/mL) after timed intervals of chamber flow, peak concentration, area under the curve and percent antimicrobial recovered. Activity of vancomycin after mixing with Osteo- Set, DBX and Collagraft was > 73%. Activity of gentamicin after mixing with DBX was 100%; after mixing with OsteoSet and Collagraft it was reduced to < 61%. AUC0-48hrs of vancomycin was 469, 426 and 432 microg x hr/mL, and the AUC0-48hrs of gentamicin was 368, 306 and 301 microg x hr/mL after release from OsteoSet, DBX, and Collagraft, respectively. Recovered percentages of vancomycin were 39%, 11% and 25%, and recovered percentages of gentamicin were 39%, 9% and 23% after release from OsteoSet, DBX, and Collagraft, respectively. OsteoSet, DBX and Collagraft may be suitable for local delivery of vancomycin and gentamicin.