Improved LC methods for the determination of diosmin and/or hesperidin in plant extracts and pharmaceutical formulations.

Two improved, simple, selective and sensitive reversed-phase HPLC methods were developed for the determination of diosmin and hesperidin simultaneously or separately, using external or internal standard techniques, respectively. The methods were applied for determination of the diosmin and/or hesperidin in Buchu leaves and pharmaceutical dosage forms (three tablets). The methods involved very simple efficient extraction procedures, the use of a LiChrosorb RP-18 column, a mixture of methanol-water (60:40, v/v) as a mobile phase in an isocratic mode at a flow rate of 1.5 ml/min and UV detection at 345 nm. In all HPLC analysis the relative standard deviation did not exceed 1.9%. As low as 50 and 25 ng (per injection) could be detected in less than 6 min with a high degree of accuracy. This is the first report for the determination of the two flavonoids simultaneously in Buchu leaf and tablets containing them.