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Measurement of unbound cocaine in blood, brain and bile of anesthetized rats using microdialysis coupled with liquid chromatography and verified by tandem mass spectrometry
Author(s) -
Chen YenFei,
Chang ChunHao,
Wang ShauChun,
Tsai TungHu
Publication year - 2005
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.468
Subject(s) - microdialysis , chemistry , chromatography , tandem mass spectrometry , mass spectrometry , pharmacokinetics , liquid chromatography–mass spectrometry , high performance liquid chromatography , pharmacology , extracellular , biochemistry , medicine
To investigate the disposition of unbound cocaine in the rat blood, brain and bile, we demonstrate an in vivo multiple sampling microdialysis system coupled with liquid chromatography for cocaine assay and veried by tandem mass spectrometry. Three microdialysis probes were concurrently inserted into the jugular vein, bile duct and brain striatum of each anesthetized rat. After a period of 2 h post‐surgical stabilization, cocaine (10 mg kg −1 ) was administered through the femoral vein. Separation of unbound cocaine from various biological uids was applied to a reversed‐phase C 18 column (250 × 4.6 mm I.D., 5 µm). The mobile phase consisted of acetonitrile–10 m m potassium dihydrogen phosphate buffer (25:75, v/v, pH 4.0) and 0.8% diethylamine at a ow rate of 1 mL min −1 . The UV detector wavelength was set at 235 nm. The results indicate that cocaine penetrates the blood–brain barrier with a rapid distribution. However, unbound cocaine in the bile dialysate was not detectable in the UV detection. We therefore use LC–tandem mass spectrometry to detect the bile uid after cocaine administration (3 mg kg −1 , i.v.). The results indicate that cocaine goes through hepatobiliary excretion. Copyright © 2005 John Wiley & Sons, Ltd.