Effect of antibiotic impregnation time on the release of gentamicin from cryopreserved allograft bone chips: an in vitro study.

Freezing is the most common method for storing bones until use in skeletal reconstruction. However, the effect of freezing at different temperatures on antibiotic delivery from antibiotic-coated bone chips has not been evaluated. In this study, we compared antibiotic delivery in vitro from gentamicin-coated human bone stored at different temperatures impregnated for different time periods. Bone chips obtained from human femur heads were chemically cleaned and mixed with gentamicin sulfate solution for 1 h and 10 h respectively. Samples of both groups were cryopreserved for 4 months at - 20 °C, 4 months at - 80 °C, or evaluated immediately without freezing. Antibiotic release from the bone chips was measured using Bacillus subtilis as an indicator strain. Zones of inhibition and rates of gentamicin were higher for the samples impregnated for 10 h as compared to 1 h. There was no significant difference between non-cryopreservation, cryopreservation at different temperatures of - 20 and - 80 °C on the release of gentamicin from bone chips even after storage for 4 months. [ABSTRACT FROM AUTHOR]