In vivo study of hot compressing molded 50:50 poly ( dl-lactide-co-glycolide) antibiotic beads in rabbits

Abstract

The authors investigated poly ( dl-lactide-co-glycolide) beads as an antibiotic delivery system in vivo for the treatment of various surgical infections. In this study, the copolymer 50:50 poly ( dl-lactide):co-glycolide was mixed with vancomycin powder and hot compressing molded at 55 °C to form 8 mm in diameter biodegradable antibiotic beads. The antibiotic beads were implanted in the distal femoral cavities of rabbits for in vivo investigation. The local concentration of vancomycin was well above the breakpoint sensitivity concentration (the antibiotic concentration at the transition point between bacterial killing and resistance to the antibiotic) for 56 days. The release was most marked during the first day. The diameters of the sample inhibition zone ranged from 8 to 18 mm, and the relative activity of vancomycin ranged from 9.1% to 100%. Only low systemic blood levels of vancomycin were measured after beads implantation. There was no increase in the concentration of blood urea nitrogen and serum creatinine after the implantation. Histological observations showed that the bead materials were biodegradable, resorbed slowly, and did not cause a significant host reaction. This study offers a biodegradable delivery system of antibiotics to treat various surgical infections.