High-performance liquid chromatographic determination of selected flavonols in Ginkgo biloba solid oral dosage forms.

PURPOSE: This paper describes a validated high-performance liquid chromatographic (HPLC) - photodiode array (PDA) detection method to quantitate five flavonol components as markers; rutin, quercitrin, quercetin, kaempferol and isorhamnetin for use in the quality control of Ginkgo biloba dosage forms. METHODS: Separation was achieved using a minibore Phenomenex Luna 5microm C(18) (2) column with dimensions 250 x 2.00mm at 45 degrees C with a one step linear gradient using acetonitrile:formic acid (0.3%) at a flow rate of 0.4ml/min. RESULTS: The limits of quantitation for the flavonols were 2.76, 0.77, 1.11, 1.55 and 1.03microg/ml for rutin, quercitrin, quercetin, kaempferol and isorhamnetin, respectively. This method is linear over concentration ranges of 3-26microg/ml for all flavonols. Recoveries for rutin, quercitrin and kaempferol were above 94% while quercetin and isorhamnetin had average recoveries of 83% and 76%, respectively. Intraday precision did not exceed 6% and with-in day precision was better than 12% for all compounds. CONCLUSION: A suitable method was developed to identify and quantitate five relevant flavonol marker compounds and was successfully used to assay some commercially available solid oral dosage forms of Ginkgo biloba .