Stability of ciprofloxacin in peritoneal dialysis solution

The long-term stability of ciprofloxacin in dialysis fluid was studied. Ciprofloxacin was added to nine 2-L bags of dialysis solution containing 1.3% dextrose to yield a nominal concentration of 25 mg/L. Three bags each were stored at 4, 20, and 37 degrees C; three 20-mL samples were removed from each bag after 0, 0.5, 1, 2, 5, 7, 10, 14, 21, 28, and 42 days and analyzed in triplicate by high-performance liquid chromatography. Additional samples were removed from each bag on day 42 and analyzed by microbiological assay with Pseudomonas aeruginosa (nine samples tested for each storage temperature studied). The net percentage of change in ciprofloxacin concentration was 0.76% after storage at 4 degrees C, 1.02% after storage at 20 degrees C, and 0.75% after storage at 37 degrees C. Antimicrobial activity after storage at all three temperatures was confirmed by microbiological assay. Ciprofloxacin 25 mg/L was stable for 42 days when stored in dialysis fluid containing 1.36% dextrose at 4, 20, and 37 degrees C.