The release of cefazolin and gentamicin from biodegradable PLA/PGA beads.

Infection has been one of the most common causes of problems and complications after the operation despite the advance in surgical techniques and the availability of newly developed antibiotics. Local antibiotic delivery beads for treatment of various surgical infections had been studied recently especially in osteomyelitis. This current paper used cefazolin sodium and gentamicin sulfate combined with biodegradable polymers (50:50 poly(DL-lactide):co-glycolide) as antibiotic beads for a long-term drug release. To manufacture an antibiotic bead, polylactide-polyglycolide copolymers were mixed with the antibiotics. The mixture was compressed and sintered at 55 degrees C to form beads of different sizes. The beads were placed in 3 ml of phosphate buffered saline and incubated at 37 degrees C. An elution method combined with a bacterial inhibitory test was employed to characterize the release rate of the antibiotics over a 30-day period. The results suggested that the biodegradable beads released high concentrations of antibiotic (well above the minimum inhibitory concentration) in vitro for the period of time needed to treat bone infection; i.e. 2-4 weeks. This provides advantages as a first line choice of long-term antibiotics for patients with osteomyelitis and various infections such as thoracic, abdominal, and pelvic infections, as well as for the prophylaxis of these infections.