Stability of foscarnet sodium in 0.9% sodium chloride injection

The stability of foscarnet sodium in 0.9% sodium chloride injection was studied. Foscarnet sodium 24 mg/mL was added to polyvinyl chloride i.v. bags containing 0.9% sodium chloride injection to give a theoretical foscarnet sodium concentration of 12 mg/mL. Ten bags of solution were stored at 25 degrees C in normal laboratory light, 10 bags were stored at 25 degrees C in the dark, and 10 bags were stored at 5 degrees C in the dark. Samples were analyzed for foscarnet concentration by high-performance liquid chromatography on days 0, 3, 8, 10, 15, and 30. The solutions were visually inspected for particulates, and pH was measured. Foscarnet sodium was stable in all the solutions for up to 30 days under all the storage conditions; mean foscarnet concentrations did not decline below 99% of initial values. No particulates appeared, and there were no important changes in pH. Foscarnet sodium 12 mg/mL in 0.9% sodium chloride injection was stable for up to 30 days when stored at 25 degrees C and exposed to light, 25 degrees C and protected from light, or 5 degrees C and protected from light.