Stability of Antibiotics for Intraperitoneal Administration in Extraneal 7.5% Icodextrin Peritoneal Dialysis Bags (STAB Study).

UNLABELLED: ♦

BACKGROUND AND OBJECTIVES: Patients with peritoneal dialysis (PD)-associated peritonitis may be advised to store PD-bags with pre-mixed antibiotics at home, although there is a paucity of antibiotic stability studies in the commonly used icodextrin solutions. The purpose of this study was to assess the stability of various antibiotics in PD-bags when stored at different temperatures over a 14-day period. ♦

METHODS: 7.5% icodextrin PD-bags were dosed with gentamicin 20 mg/L (n = 9), vancomycin 1,000 mg/L (n = 9), cefazolin 500 mg/L (n = 9) and ceftazidime 500 mg/L (n = 9) as for intermittent dosing. Combinations of gentamicin/vancomycin (n = 9), cefazolin/ceftazidime (n = 9), and cefazolin/gentamicin (n = 9) were also tested. Nine drug-free bags were used as controls. Bags were stored in triplicate at 37°C, room-temperature (25°C), and refrigeration (4°C). Antibiotic concentrations were quantified at various time intervals using validated chromatography. Storage duration was considered unstable if the concentration of the antibiotic dropped ≤ 90% of the initial value. ♦

RESULTS: Gentamicin was stable for 14 days at all temperatures. Vancomycin was stable for 4 days at 37°C and for 14 days at both 25°C and 4°C. The gentamicin and vancomycin combination was stable for 4 days at 37°C and for 14 days at 25°C and 4°C. Cefazolin alone was stable for 24 hours at 37°C, 7 days at 25°C, and 14 days at 4°C. Ceftazidime alone was stable for only 6 hours at 37°C, 2 days at 25°C, and 14 days at 4°C. The cefazolin and ceftazidime combination was stable for 24 hours at 37°C, 2 days at 25°C, and 14 days at 4°C. The cefazolin and gentamicin combination was stable for 1 day at 37°C, 4 days at 25°C, and 14 days at 4°C. ♦

CONCLUSIONS: Antibiotics premixed in icodextrin PD-bags have varying stabilities with stability generally least at 37°C and best at 4(o)C, permitting storage for 14 days when refrigerated and prewarming to body temperature prior to administration. Further research confirming the sterility of these antibiotic-containing bags is recommended.