Bonding of ofloxacin to polytetrafluoroethylene suture and colonization by Staphylococcus aureus

Conditions required for in vitro bonding of¹⁴C-ofloxacin (OFX) to polytetrafluoroethylene suture (PTFE) were investigated. Bonding of OFX to PTFE was enhanced 22- and 75-fold in the presence of the cationic surfactant benzalkonium chloride (BAC) or silver and organic solvents (S/O), respectively. The optimal temperature and time of incubation for maximum OFX bonding was 37°C for 1 h (BAC) and 37°C for 25 min (S/O). BAC- and S/O-treated PTFE bound 3.94 nmoles and 17.79 nmoles OFX/cm suture. Prolonged in vitro incubation of OFX/PTFE for 7 days at 37°C in the presence of serum or saline resulted in 50% OFX retention. In vivo studies on OFX/PTFE placed into canine carotid arteries showed 8% OFX retention. The intravenous infusion of coagulase-positive Staphylococcus aureus into OFX/PTFE animals resulted in colonization. Although significant in vitro bonding of OFX to PTFE was observed, in vivo studies demonstrate an accelerated release and inferior OFX/PTFE activity against microbial colonization.