title: HPLC with electrochemical detection to examine the pharmacokinetics of baicalin and baicalein in rat plasma after oral administration of a Kampo medicine.
abstract: A highly sensitive method for determining baicalin and baicalein in rat plasma was developed using micro HPLC with electrochemical detection (muHPLC-ED). Peak heights for baicalin and baicalein were found to be linearly related to the amounts injected, ranging from 2.2 pg to 4.5 ng (r = 0.997) and from 1.4 pg to 2.7 ng (r = 0.997), respectively. The detection limits (signal/noise ratio = 3) of the current method for baicalin and baicalein were 0.89 and 0.54 pg, respectively. The concentrations of baicalin, baicalein, and their conjugates in rat plasma after oral administration of 2.0 mg/kg of Saiko-keishi-to (TJ-10) were determined. The glucuronide and sulfate forms of baicalin and baicalein in plasma were hydrolyzed enzymatically using beta-glucuronidase and sulfatase, respectively, and the hydrolyzed solutions were extracted with a 0.1-mol/L phosphoric acid-ethyl acetate mixture (1:1, v/v). Based on the time courses of the concentrations of the free and conjugated forms of baicalin and baicalein in rat plasma after oral administration of Saiko-keishi-to, the pharmacokinetic parameters of C(max), t(max), and AUC(0-6 h) were obtained.
authors.affiliation: Department of Analytical Chemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kotani
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kojima
authors.forename: Hideki
authors.initials: H
authors.lastname: Hakamata
authors.forename: Fumiyo
authors.initials: F
authors.lastname: Kusu
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage* / Q000493:pharmacokinetics; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D005419:Flavonoids / Q000493:pharmacokinetics*; D066298:In Vitro Techniques; D008297:Male; D008832:Microchemistry / Q000295:instrumentation / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004365:Drugs, Chinese Herbal; D005419:Flavonoids; C413305:baicilein; C038044:baicalin; C018142:saiko-keishi-to