Stability of ceftazidime and vancomycin alone and in combination in heparinized and nonheparinized peritoneal dialysis solution

OBJECTIVE: To examine the stability of ceftazidime, vancomycin, and heparin, alone and in combination, in dialysis solution over six days at three temperatures. DESIGN: Nine 250-mL Dianeal PD-2 dextrose 1.5% bags were prepared with ceftazidime, vancomycin, and heparin alone and in combination at set concentrations of 100 micrograms/mL, 50 micrograms/mL, and 1 unit/mL, respectively. Three bags of each mixture were stored at 4, 25, and 37 degrees C. Duplicate samples for analysis were removed from each bag at the following time points: premix, 0, 12, 24, 48, 72, 96, 120, and 144 hours. MAIN OUTCOME MEASURES: Each sample was examined visually for signs of cloudiness and precipitation. Each sample was analyzed by stability-indicating HPLC assay for ceftazidime and vancomycin, with stability defined as less than 10 percent degradation of drug over time. RESULTS: No color change or precipitation was observed in any bag. Vancomycin with or without heparin was stable for 5-6 days at 4, 25, and 37 degrees C. Ceftazidime with and without heparin was stable for 6 days at 4 degrees C, 4 days at 25 degrees C, and less than 12 hours at 37 degrees C. Vancomycin plus ceftazidime with and without heparin was stable for 6 days at 4 degrees C and 25 degrees C, and 4-5 days at 37 degrees C. Ceftazidime plus vancomycin with or without heparin was stable for 6 days at 4 degrees C, 2-3 days at 25 degrees C, and 12 hours at 37 degrees C. CONCLUSIONS: Bulk preparations of ceftazidime and vancomycin, alone and in combination and with or without heparin in Dianeal PD dextrose 1.5% solution, are sufficiently stable for use up to 6 days under refrigeration or 48 hours at room temperature.