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Simultaneous quantitation of zidovudine and zidovudine monophosphate from plasma, amniotic fluid and tissues by micellar capillary electrophoresis
Author(s) -
Alnouti Yazen,
White Catherine A.,
Bartlett Michael G.
Publication year - 2004
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.350
Subject(s) - zidovudine , chemistry , chromatography , amniotic fluid , solid phase extraction , coefficient of variation , capillary electrophoresis , extraction (chemistry) , fetus , human immunodeficiency virus (hiv) , virology , pregnancy , medicine , viral disease , biology , genetics
Zidovudine (AZT) therapy given during pregnancy has been shown to reduce the vertical transmission of the human immunodeciency virus (HIV) from mother to fetus. In order to investigate the efcacy of AZT, it is important to know the concentration of its active phosphorylated metabolites. We have developed the rst CE method for the simultaneous quantitation of AZT and zidovudine monophosphate (AZT‐MP) from rat plasma, amniotic uid and fetal tissues. Sample extractions were performed by protein precipitation using acetonitrile for the plasma and amniotic uids, while in fetal tissues solid phase extraction using Waters Oasis™ HLB extraction cartridges was used. Recoveries ranged from 78 to 92% for AZT, AZT‐MP and 3′‐azidouridine (internal standard, AZDU), in the three matrices. The optimum separation conditions were achieved using a 40 m m sodium dodecylsulfate (SDS) in 50 m m phosphate buffer (pH 7) with a run voltage of 15 kV. The CE system consists of a 75 µm i.d., 50 cm effective length uncoated fused silica capillary. The method was validated over the range 0.5–100 µg/ml (µg/g for tissues). Intra‐day precision (RSD) and accuracy (%error) for AZT ranged from 0.13 to 11 and 0.68 to 11.1%, respectively, while for AZT‐MP it ranged from 2.05 to 11.1 and 4.22 to 11.7%. Inter‐day precision and accuracy for AZT ranged from 3.82 to 11.2 and 3.14 to 9.01%, while for AZT‐MP it ranged from 3.9 to 9.32 and 3.44 to 9.37%, respectively. We also report the enzymatic dephosphorylation of AZT‐MP in the placental tissue of rats. This new enzymatic pathway provides increased understanding of the mechanism of anti‐viral transport in the rat during pregnancy. Copyright © 2004 John Wiley & Sons, Ltd.