Urinary Excretion of Ecgonine Methyl Ester, a Major Metabolite of Cocaine in Humans

Urinary Excretion of Ecgonine Methyl Ester, a Major Metabolite of Cocaine in Humans / John Ambre, Marian Fischman, Tsuen-ih Ruo. - (Journal of Analytical Toxicology 8 (1984) 1 (January/February); p. 23-25)

  • DOI: 10.1093/jat/8.1.23


In this study, cocaine, benzoylecgonine, and ecgonine methyl ester excretion in urine was measured after intravenous and intranasal administration of cocaine at 16, 32, 48, and 96 mg doses to healthy cocaine users. Ecgonine methyl ester and cocaine were analyzed by gas chromatography/mass spectrometry. Benzoylecgonine was measured by immunoassay (EMIT) and liquid chromatography. Urinary ecgonine methyl ester accounted for 26 to 60% of the cocaine dose. Ecgonine methyl ester had an elimination halflife of 4.2 hr, compared with 5.1 hr for benzoylecgonine. These results indicate that ecgonine methyl ester accounts for most of the previously unidentified urinary metabolic products of cocaine. The time course of ecgonine methyl ester excretion is such that its detection can substitute for benzoylecgonine detection as a marker of cocaine use.

Original document


Research / Study
4 January 1984
Ambre, John
Fischman, Marian
Ruo Tsuen-ih
United States of America
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Northwestern University Feinberg School of Medicine
University of Chicago (UChicago)
Analytical aspects
Half-life / excretion time of substance
Mass spectrometry analysis
Testing method development
Doping classes
S6. Stimulants
Document category
Scientific article
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Pdf file
Date generated
18 October 2021
Date of last modification
26 October 2021
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