title: Oral and i.v. pharmacokinetics of isosteviol in rats as assessed by a new sensitive LC-MS/MS method.
abstract: A sensitive liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method was developed to investigate isosteviol pharmacokinetics in vivo. Isosteviol was extracted from plasma with hexane and 4% formic acid. A Phenomenex Synergi 2mu Fusion reversed phase analytical HPLC column (50 mm x 2.0 mm) equipped with a Synergi 2micro Fusion guard column was employed for chromatographic separations. The gradient mobile phase consisted of acetonitrile (ACN) and 20mM ammonium acetate at pH 6.5, starting at 20% ACN and ramping to 80% at 7 min, followed by 80% ACN for 1 min, then 20% ACN for 5 min. Negative SRM was used to monitor the m/z 317.1/317.1 and 317.3/317.3 transitions for isosteviol and 395.0/395.0 and 397.0/397.0 transitions for internal standard. The retention time of isosteviol was 9.2 min. The assay was linear over the range of 50-2,000 ng/mL. The accuracy of the method was in the range of 97-105%. Intra- and inter-day precisions were in the range of 1.5-4.6%. Isosteviol (4 mg/kg) was dosed intravenously and orally to Sprague-Dawley rats (n=6). Plasma samples were collected and analysed. Intravenous isosteviol has a distribution half-life of 35.7+/-9.0 min with the initial distribution volume of 68.1+/-9.4 mL. The total clearance, terminal half-life and steady-state volume of distribution were 1.25+/-0.12 mL/min, 150.6+/-50.5 min and 272.6+/-95.9 mL, respectively. The oral bioavailability of isosteviol was found to be 60.4+/-15.5%.
authors.affiliation: Sansom Institute, City East, School of Pharmacy and Medical Science, University of South Australia, Adelaide, SA 5000, Australia.
authors.forename: Hongping
authors.initials: H
authors.lastname: Jin
authors.forename: Jacobus P
authors.initials: JP
authors.lastname: Gerber
authors.forename: Jiping
authors.initials: J
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Ji
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Davey
mesh_terms: D000085:Acetates / Q000737:chemistry; D000097:Acetonitriles / Q000737:chemistry; D000284:Administration, Oral; D000818:Animals; D019540:Area Under Curve; D001682:Biological Availability; D002138:Calibration; D002853:Chromatography, Liquid / Q000295:instrumentation / Q000379:methods*; D045786:Diterpenes, Kaurane / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D004355:Drug Stability; D005615:Freezing; D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D007275:Injections, Intravenous; D008297:Male; D008657:Metabolic Clearance Rate; D015394:Molecular Structure; D051381:Rats; D017207:Rats, Sprague-Dawley; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012997:Solvents / Q000737:chemistry; D013549:Sweetening Agents / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D053719:Tandem Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D013696:Temperature
chemical_list: D000085:Acetates; D000097:Acetonitriles; D045786:Diterpenes, Kaurane; D012997:Solvents; D013549:Sweetening Agents; C515747:isosteviol; C018824:ammonium acetate; C032159:acetonitrile