Stability of antibiotics used for antibiotic-lock treatment of infections of implantable venous devices (ports).

Antibiotic-lock is a treatment for catheter-related bloodstream infections in which a solution containing heparin and an antibiotic dwells in the lumen of the catheter or port. We tested the stability of vancomycin, cefazolin, ticarcillin-clavulanic acid, ceftazidime, or ciprofloxacin combined with heparin after incubation in vitro at 25 or 37 degrees C for intervals of up to 10 days by bioassay. All the antibiotic solutions except ceftazidime retained >/=90% activity at both 25 and 37 degrees C. Thus, studies of antibiotic-heparin lock solutions with dwell times of up to 10 days are feasible.