Stability of aqueous solutions of deferoxamine

The stability of deferoxamine in 10 mM phosphate buffer solutions between pH 1.9 and 10.1 was studied at - 20°C, 4°C, 23°C and 37°C. Solutions were stored in glass test tubes and PVC containers. The deferoxamine concentration was measured on day 0, 1, 2, 3, 4, 5, 10, 18 and 30, using a liquid chromatographic method. Deferoxamine degrades quickly in alkaline (pH = 10.1) or acidic (pH = 1.9) solutions. However, between a pH of four and six deferoxamine retains more than 90 percent of the initial concentration when stored at temperatures of 23°C or lower. At 37°C, even at a pH between four and six, more than 10 percent of deferoxamine is lost over 30 days.