Sustained elution of amikacin, clindamycin, and vancomycin from a biodegradable cross-linked dextran gel.

Osteomyelitis, surgical site infections, implant infections, abscesses, and other localized infections can be difficult to treat due to poor vascularity, biofilm formation, and the presence of antibiotic-resistant bacteria. These infections result in significant morbidity and mortality in human and veterinary patients. Local delivery of high concentrations of antibiotics that are released over a prolonged period of time can overcome these issues, and avoid side effects of systemic antibiotics. In vitro release kinetics of amikacin, clindamycin, and vancomycin from a cross-linked dextran (CLD) gel were investigated. The hypothesis was that CLD gel containing vancomycin, amikacin, clindamycin or a combination of amikacin and clindamycin would elute concentrations above the MIC of common bacterial pathogens for 7 days in vitro. Elution kinetics of CLD gels impregnated with each antibiotic and control gel were tested an in vitro. Each gel was incubated with phosphate-buffered saline at 37 °C with agitation in triplicate. The media was changed every 24 h. Samples from the experimental and control gels were collected for a period of 16 days and antibiotic concentrations were determined. Mean antibiotic concentrations from CLD gel remained above the MIC for at least 7 days for each of the antibiotics investigated. Peak mean antibiotic concentrations occurred at 24 h. In sum, there is reliable elution over 7 days of amikacin, clindamycin and vancomycin from CLD gel at clinically relevant concentrations.