abs: In Vitro Elution Characteristics of Meropenem, Ampicillin/Sulbactam, Cefazolin, Amikacin, and Gentamicin from a Commercially Available Calcium Sulfate Local Antibiotic Delivery Kit Strategies to Combat MDR & Biofilm Infections
Advanced Veterinary Care Center Boca Raton, Florida
The primary objective of this study was to describe the elution kinetics of five antibiotics from a commercially available calcium sulfate local antibiotic delivery kit. A secondary goal was to compare elution concentrations with minimal inhibitory concentration for commonly encountered bacteria from the University of Florida’s veterinary microbiology laboratory database. Calcium sulfate powder was combined with amikacin, cefazolin, gentamicin, ampicillin/sulbactam, and meropenem (ratio: 20 g of CSH, to 500 mg, 1 g, 400 mg, 750 mg, and 500 mg of antibiotic, respectively). Triplicates of antibiotic-loaded beads were immersed in 5 mL of phosphate-buffered saline (PBS) and kept at 37°C under constant agitation. Antibiotic-conditioned PBS was sampled at fourteen time points (1, 3, 6, 12, 24 h; 3, 6, 9, 12, 15, 18, 22, 26, 30 d) and analyzed by liquid chromatography to determine the antibiotic concentration. All beads eluted concentration of antibiotic for the 30-day sampling period, except for ampicillin/sulbactam, with the most antibiotic being eluted within the first week. Mean observed peak concentrations occurred at 1 hour for all antibiotics, with a biphasic peak for all antibiotics, except ampicillin/sulbactam. It was observed that the 5-mm bead samples were superior in maintaining higher concentrations for a longer period, compared to the 3-mm beads. The study evaluated elution kinetics of 3 beads per size, which is less than the amount used to treat local infection. This information may be useful for clinical decision making for treatment of local infections encountered during surgical procedures.
