A rapid and sensitive spectrophotometric method for the determination of diosmin (D) has been developed. The
method is based on the reaction of D with 4-aminoantipyrine (AAP) in the presence of hexacyanoferrate (III) (HCF) in an
alkaline medium and subsequent formation of a purple coloured product having λmax at 524.5 nm. The conditions affecting
the reaction (reagents concentration, pH, order of addition of reagents, stability in time) were optimized. Under the
optimum conditions, Beer’s law was obeyed in the range of 0.3 – 35 μg mL-1 D with a correlation coefficient of 0.9993.
The assay limits of detection and quantitation were 0.1 and 0.3 μg mL-1, respectively. The proposed method was
successfully applied to the analysis of the drug tablets formulation. The results were compared favorably with those
obtained by other reported methods.