Chemical stability of suramin in commonly used infusion fluids

The chemical stability of suramin in NaCl 0.9%, dextrose 5%, and lactated Ringer's injection was investigated. The admixtures were stored in glass infusion bottles at 4 degrees C in the dark, and at room temperature (22 degrees C) both protected from light and under normal room fluorescent light conditions in a day-night rhythm. The initial concentration of suramin was approximately 1 mg/mL. Samples withdrawn immediately after preparation and at four hours, one, two, three, five, and seven days were analyzed by HPLC with ultraviolet (UV) detection. Samples were also inspected for visual changes and tested for changes in pH. Accelerated stability studies in NaCl 0.9% injection were executed at 90 degrees C. The drug appeared to be stable under the chosen storage conditions with no visual changes or changes in pH. The accelerated experiments revealed that suramin degrades in NaCl 0.9% at 90 degrees C with a half-life of about 5.5 hours. It is concluded that suramin 1 mg/mL is stable in NaCl 0.9%, dextrose 5%, and lactated Ringer's injections when stored in glass infusion bottles at 4 degrees C in the dark and at 22 degrees C under normal room light conditions in a day-night rhythm or protected from light for at least seven days.