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Clinical Chemistry 46: 1787-1795, 2000;
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(Clinical Chemistry. 2000;46:1787-1795.)
© 2000 American Association for Clinical Chemistry, Inc.

Articles

Stability of Methylecgonidine and Ecgonidine in Sheep Plasma in Vitro

Karl B. Scheidweiler1, Jalil Shojaie2, Mark A. Plessinger2, Ronald W. Wood2 and Tai C. Kwong1,a

University of Rochester School of Medicine, Departments of
1 Pathology and Laboratory Medicine and
2 Obstetrics and Gynecology, Rochester, NY 14642.
a Address correspondence to this author at: Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, 601 Elmwood Ave., Box 608, Rochester, NY 14642. Fax 716-273-3003; e-mail Tai_Kwong{at}urmc.rochester.edu

Background: Crack smokers are exposed to a pyrolysis product, methylecgonidine (MEG), which can be used as an analytical marker for crack smoking. Ecgonidine (EC), a hydrolytic product of MEG, has been identified in urine of crack smokers. MEG undergoes conversion to EC, complicating analysis and perhaps explaining a lack of forensic blood specimens containing MEG.

Methods: We developed gas chromatography–mass spectrometry (GC-MS) assays for MEG and EC. Plasma was collected from sheep blood containing 0, 0.06, or 0.24 mol/L (0%, 0.25%, or 1%) NaF. MEG was added to these plasmas, and they were incubated at -80, 1, 21, or 37 °C to determine whether there were temporal, temperature, or storage effects on MEG stability over 48 h.

Results: Decreased temperature and increased NaF concentrations limited MEG degradation and EC formation. MEG stored in plasma at -80 °C was stable up to 1 month, even in the absence of NaF.

Conclusions: MEG is stable in sheep plasma collected in commercially available, evacuated blood-collection tubes containing NaF and stored at -80 °C. In vitro formation of EC can be minimized with appropriate sample handling, and its in vivo formation may provide a better marker of crack smoking than its parent pyrolysis product.




The following articles in journals at HighWire Press have cited this article:


Home page
 J. Pharmacol. Exp. Ther.Home page
K. B. Scheidweiler, M. A. Plessinger, J. Shojaie, R. W. Wood, and T. C. Kwong
Pharmacokinetics and Pharmacodynamics of Methylecgonidine, a Crack Cocaine Pyrolyzate
J. Pharmacol. Exp. Ther., December 1, 2003; 307(3): 1179 - 1187.
[Abstract] [Full Text] [PDF]

Home page
 Clin. Chem.Home page
E. T. Shimomura, G. D. Hodge, and B. D. Paul
Examination of Postmortem Fluids and Tissues for the Presence of Methylecgonidine, Ecgonidine, Cocaine, and Benzoylecgonine Using Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry
Clin. Chem., June 1, 2001; 47(6): 1040 - 1047.
[Abstract] [Full Text] [PDF]


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