title: Determination of human plasma protein binding of baicalin by ultrafiltration and high-performance liquid chromatography.
abstract: A simple and selective HPLC assay was developed and utilized for determination of human plasma protein binding of baicalin. The method involved solid-phase extraction and reversed-phase chromatographic separation with a mobile phase of acetonitrile-0.02 mol/L phosphate buffer (pH 2.5; 25:75, v/v) and UV detection at 276 nm. The standard curve for baicalin was linear over the concentration range 0.1-20 microg/mL and the limit of detection was 0.02 microg/mL. The absolute recovery was greater than 76%. The intra-day and inter-day variations were less than 10%. Ultrafiltration technique was applied to determining the plasma protein binding of baicalin in human plasma. Results show the plasma protein binding of baicalin was in the range 86-92% over all the concentrations studied and the protein binding association constant was determined to be 1.21 x 10(5) L/mol at 4 degrees C.
authors.affiliation: Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, People's Republic of China.
authors.forename: Yihong
authors.initials: Y
authors.lastname: Tang
authors.forename: Haiyan
authors.initials: H
authors.lastname: Zhu
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Chenggang
authors.initials: C
authors.lastname: Huang
mesh_terms: D001798:Blood Proteins / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005419:Flavonoids / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D015394:Molecular Structure; D011485:Protein Binding; D015203:Reproducibility of Results; D014462:Ultrafiltration / Q000379:methods*
chemical_list: D001798:Blood Proteins; D005419:Flavonoids; C038044:baicalin