title: High-performance liquid chromatographic determination of selected flavonols in Ginkgo biloba solid oral dosage forms.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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 .
authors.affiliation: Division of Pharmaceutics, Faculty of Pharmacy, Rhodes University, Grahamstown, South Africa.
authors.forename: Mary-Jean
authors.initials: MJ
authors.lastname: Dubber
authors.forename: Isadore
authors.initials: I
authors.lastname: Kanfer
mesh_terms: D000284:Administration, Oral; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D044948:Flavonols / Q000032:analysis*; D020441:Ginkgo biloba / Q000737:chemistry*; D044949:Kaempferols / Q000032:analysis; D010946:Plants, Medicinal; D011786:Quality Control; D011794:Quercetin / Q000031:analogs & derivatives / Q000032:analysis; D012431:Rutin / Q000031:analogs & derivatives / Q000032:analysis
chemical_list: D044948:Flavonols; D044949:Kaempferols; C047368:3-methylquercetin; C056067:rutin sulfate; C012526:quercitrin; D012431:Rutin; C006552:kaempferol; D011794:Quercetin