Quantification of α- and β-amyrin in rat plasma by gas chromatography–mass spectrometry: application to preclinical pharmacokinetic study

✍ Scribed by Jianhong Ching; Hai-Shu Lin; Chay-Hoon Tan; Hwee-Ling Koh

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 188 KB
• Volume: 46
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/jms.1912

✦ Synopsis

Abstract

α‐ and β‐Amyrins are naturally occurring triterpenes with a wide range of biological activities. In this study, a reliable GC‐MS method was developed and validated for the quantification of α‐ and β‐amyrins in rat plasma. The calibration curves were linear (R^2^ > 0.996) with a limit of quantification of 1.0 ng ml^−1^ for both α‐ and β‐amyrins. The precision and repeatability of this method was good as the relative standard deviation were 12% or less. The absolute recovery ranged from 71% to 89%, while the analytical recovery ranged from 95% to 99%. The pharmacokinetic profiles of α‐ and β‐amyrins in rats were subsequently investigated in Sprague‐Dawley rats. β‐Amyrin was administered intravenously and also orally in two forms, namely, as a suspension of the pure compound and the crude plant extract. α‐Amyrin was administered orally as a suspension of the crude plant extract. β‐Amyrin had a very long terminal elimination half‐life (t~1/2λ__z__~ = 610 ± 179 min) and extremely slow clearance (Cl = 2.04 ± 0.24 ml min^−1^ kg^−1^). The absolute oral bioavailability of β‐amyrin in the crude plant extract was about fourfold higher than that in the suspension of pure form (3.83% vs 0.86%). When given in crude plant extract, both α‐ and β‐amyrins had a similar dose normalized C~max~. This reliable GC‐MS method will enable further pharmacokinetic investigations of α‐ and β‐amyrins. Copyright © 2011 John Wiley & Sons, Ltd.