title: Determination of metformin in plasma by capillary electrophoresis using field-amplified sample stacking technique.
abstract: A capillary electrophoresis method was described for the determination of metformin in human plasma based on the extraction of the ion-pair with bromothymol blue into chloroform. Phenformin was used as internal standard. Field-amplified sample stacking injection was employed with an electrokinetic injection voltage of 10 kV for 10 s. The running buffer was 0.1 M phosphate buffer (pH 2.5), running voltage was 20 kV and the UV absorbance detection was set at 195 nm. The limit of quantitation was 0.25 microg/ml. Linearity range of calibration curve was 0.25 to 3.5 microg/ml. Recoveries for three levels (0.25, 1 and 2 microg/ml) were 80.24%, 67.44% and 58.97% (n = 5 for each level), respectively. The intra-day precisions for the three levels were 11.9%, 3.09% and 4.33% and the inter-day precisions were 12.4%, 4.57% and 4.94%, respectively. The concentrations of metformin hydrochloride in human plasma of eight volunteers were measured after orally administrating metformin enteric-capsule and tablet.
authors.affiliation: Division of Instrumental Analysis, National Institute for the Control of Pharmaceutical and Biological Products, Temple of Heaven, Beijing, China.
authors.forename: J Z
authors.initials: JZ
authors.lastname: Song
authors.forename: H F
authors.initials: HF
authors.lastname: Chen
authors.forename: S J
authors.initials: SJ
authors.lastname: Tian
authors.forename: Z P
authors.initials: ZP
authors.lastname: Sun
mesh_terms: D004355:Drug Stability; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D008687:Metformin / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D008687:Metformin