Fluorimetric determination of diosmin and hesperidin in combined dosage forms and in plasma through complex formation with terbium

A sensitive and simple fluorimetric method was developed for the determination of diosmin and hesperidin. The proposed method involves the formation of ternary complex with Tb3+ in the presence of Tris buffer. The fluorescence quenching of Tb3+ at 549 and 494 nm (λex at 275 and 248 nm) due to the complex formation was quantitatively measured for diosmin and hesperidin, respectively. The reaction conditions and the fluorescence spectral properties of the complexes have been investigated. Under the described conditions, the proposed method was applicable over the concentration range (4.93 × 10−6–1.81 × 10−5 mol) and (3.28 × 10−6–1.64 × 10−5 mol) with mean percentage recoveries 100.22 ± 0.89 and 99.13 ± 0.72 for diosmin and hesperidin, respectively. The proposed method was applied successfully for the determination of studied drugs in bulk powder, dosage forms and plasma samples. The results obtained by applying the described method were statistically analyzed and compared with those obtained by applying a reported method. The method was validated according to ICH recommendations.