The stability of levofloxacin in 10 commonly used infusion fluids was studied. Levofloxacin 25-mg/mL injection was diluted to 0.5 and 5 mg/mL in each of the following i.v. infusion fluids: 0.9% sodium chloride injection, 5% dextrose injection, 5% dextrose and 0.9% sodium chloride injection, 5% dextrose and lactated Ringer's injection, 5% sodium bicarbonate injection, Plasma-Lyte 56 and 5% dextrose injection, 5% dextrose and 0.45% sodium chloride and 0.15% potassium chloride injection, 1/6 M sodium lactate injection, sterile water for injection, and 20% mannitol injection. Ten polyvinyl chloride bags were prepared for each solution; two were stored for 3 days at 25 degrees C, two for 7 days at 5 degrees C, two for 14 days at 5 degrees C, two for 13 weeks at -20 degrees C followed by 14 days at 5 degrees C, and two for 26 weeks at -20 degrees C followed by 14 days at 5 degrees C, all in the dark. The solutions were visually examined, tested for turbidity and particulate matter, and subjected to stability indicating high-performance liquid chromatography; solution pH was determined. Levofloxacin was stable in and compatible with all but two of the diluents tested. Precipitation occurred under all conditions in 20% mannitol injection for the 0.5-mg/mt levofloxacin concentration and after storage for 13 weeks at -20 degrees C for the 5-mg/mt concentration. Levofloxacin 0.5 mg/ml in 5% sodium bicarbonate injection formed a precipitate when stored at -20 degrees C for 13 weeks and beyond. Levofloxacin 0.5 and 5 mg/mt was compatible with and stable in 8 of the 10 infusion fluids studied.
