title: Determination of metformin in human plasma by high-performance liquid chromatography.
abstract: A simple, selective and sensitive high-performance liquid chromatographic method with spectrophotometric detection was developed for the determination of antihyperglycemic agent metformin in human plasma using a novel sample extraction procedure. Liquid-liquid extraction of metformin and ranitidine (as internal standard) from plasma samples was performed with 1-butanol/n-hexane (50:50, v/v) in alkaline condition followed by back-extraction into diluted acetic acid. Chromatography was carried out using a silica column (250 mmx4.6 mm, 5 microm) under isocratic elution with acetonitrile-40 mM aqueous sodium dihydrogen phosphate (25:75, v/v), pH 6. The limit of quantification (LOQ) was 15.6 ng/ml and the calibration curves were linear up to 2000 ng/ml. The mean absolute recoveries for metformin and internal standard using the present extraction procedure were 98 and 95%, respectively. The intra- and inter-day coefficient of variation and percent error values of the assay method were all less than 8.3%.
authors.affiliation: Laboratory of Bioanalysis, Department of Pharmacology, Neuroscience Research Center, Shaheed Beheshti University of Medical Sciences, P.O. Box 19835-355, Tehran, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Amini
authors.forename: Abolhassan
authors.initials: A
authors.lastname: Ahmadiani
authors.forename: Parisa
authors.initials: P
authors.lastname: Gazerani
mesh_terms: D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D007004:Hypoglycemic Agents / Q000097:blood*; D008687:Metformin / Q000097:blood* / Q000592:standards; D012015:Reference Standards; D015203:Reproducibility of Results
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin