Spectrophotometric Determination of Hydroxyurea in Pharmaceutical Preparations


A simple spectrophotometric method for the determination of hydroxyurea has been developed. The method is based on the oxidation of hydroxyurea with iron(III) in acidic medium, and the liberated iron(II) reacts with 1,10-phenanthroline to form the orange-red chelate which has a maximum absorption at 510 nm. Beer's law is obeyed over the concentration range 5-160 μg of hydroxyurea in a final volume of 25 ml, with a molar absorptivity of 2.36×104 l.mol-1.cm-1 and Sandell's sensitivity index of 0.0032 μg.cm-2, a relative error of -2.4 to +1.6% and a relative standard deviation of ±0.32 to ±1.5%, depending on the concentration level. Interferences due to excipients have been examined. The proposed method has been applied successfully to the determination of hydroxyurea in pharmaceutical formulations (capsules).