Quantitation of entacapone glucuronide in rat plasma by on-line coupled restricted access media column and liquid chromatography–tandem mass spectrometry |
| |
Authors: | Helena Keski-Hynnil Knut Raanaa Markus Forsberg Pekka Mnnist Jyrki Taskinen Risto Kostiainen |
| |
Institution: | a Department of Pharmacy, Division of Pharmaceutical Chemistry, P.O. Box 56, University of Helsinki, FIN-00014 Helsinki, Finland;b School of Pharmacy, University of Oslo, P.O. Box 1068, Blindern, 0316 Oslo, Norway;c Department of Pharmacology and Toxicology, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland;d Viikki Drug Discovery Technology Center, Department of Pharmacy, P.O. Box 56, University of Helsinki, FIN-00014 Helsinki, Finland |
| |
Abstract: | A column-switching liquid chromatography–electrospray ionization-tandem mass spectrometric (LC–ESI-MS–MS) method was developed for the direct analysis of entacapone glucuronide in plasma. The plasma samples (5 μl) were injected onto a C18-alkyl-diol silica (ADS) column and the matrix compounds were washed to waste with a mixture of 20 mM ammonium acetate solution at pH 4.0–acetonitrile (97:3). The retained analyte fraction containing (E)- and (Z)-isomers of glucuronides of entacapone and tolcapone glucuronide (internal standard) was backflushed to the analytical C18 column, with a mixture of 20 mM ammonium acetate–acetonitrile (85:15) for the final separation at pH 7.0. The eluate was directed to the mass spectrometer after splitting (1:100). The mass spectrometer was operated in the negative ion mode and the deprotonated molecules M−H]− were chosen as precursor ions for the analytes and internal standard. Collisionally induced dissociation of M−H]− in MS–MS resulted in loss of the neutral glucuronide moiety and in the appearance of intensive negatively charged aglycones M−H−Glu]−, which were chosen as the product ions for single reaction monitoring. Quantitative studies showed a wide dynamic range (0.0025–100 μg/ml) with correlation coefficients better than 0.995. The method was repeatable within-day (relative standard deviation, RSD<7%) and between-day (RSD<14%) and the recovery (78–103%) was better than with the traditional, laborious pretreatment method. The use of tandem mass spectrometry permitted low limits of detection (1 ng/ml of entacapone glucuronide). The method was applied for the quantitation of (E)- and (Z)-isomers of entacapone glucuronide in plasma of rats used in absorption studies. |
| |
Keywords: | Entacapone glucuronide |
本文献已被 ScienceDirect 等数据库收录! |
|