Stability of furosemide in human albumin solution

OBJECTIVE: To determine the chemical stability of furosemide in human albumin solution over a 28-day period and to assess admixtures for microbiologic contamination. METHODS: Samples were prepared by mixing furosemide injectable solution and 25% human albumin solution in a 1:1 molar ratio. Six bulk containers were prepared and stored in the dark: 3 under refrigeration (approximately 4 degrees C) and 3 at room temperature (approximately 25 degrees C). Study samples were withdrawn from each bulk solution immediately after preparation and at predetermined intervals over the subsequent 28 days. Containers were observed for color change and precipitation against a light and dark background at each sampling interval. Total furosemide concentration was determined using HPLC. Additional vials were prepared and assessed for microbiologic growth at time points corresponding with chemical stability results. RESULTS: A mean of 94.5%+/-1.33% of the initial furosemide concentration remained after 48 hours at room temperature. Under refrigeration, 100.6%+/-1.02% of the initial concentration remained at 14 days. Beyond these respective time points, <90% of the initial furosemide concentration remained. No bacterial or fungal growth was observed. CONCLUSIONS: When combined with 25% human albumin solution and stored under darkness, furosemide is chemically stable and free of microbiologic contamination for 48 hours at room temperature and 14 days under refrigeration.