Disposition of cocaine and its metabolites in human sweat after controlled cocaine administration

Sherri L. Kacinko, Allan J. Barnes, Eugene W. Schwilke, Edward J. Cone, Eric T. Moolchan, Marilyn A. Huestis

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Background: Sweat testing is a noninvasive technique for monitoring drug exposure in treatment, criminal justice, and employment settings. Methods: We evaluated cocaine excretion in 9 participants' sweat after they received 3 low doses (75 mg/70 kg) of cocaine HCl subcutaneously within 1 week and, 3 weeks later, 3 high doses (150 mg/70 kg). Six additional participants completed portions of the study. Pharm-Chek® sweat patches (n = 1390) were collected throughout a 3-week washout period, reflecting previously self-administered drugs, and during and after controlled dosing. Results: Cocaine was the primary analyte detected with 24% of patches positive at the gas chromatography-mass spectrometry limit of quantification of 2.5 ng/patch and 7% of patches at the proposed Substance Abuse and Mental Health Services Administration cutoff of 25 ng/patch. Ecgonine methyl ester (EME) was detected more often and at generally higher concentrations than benzoylecgonine. In patches containing both metabolites, there was no statistically significant difference in the benzoylecgonine/EME ratio based on length of patch wear. During washout, 2 participants' weekly patches tested positive (≥25 ng/patch) during the first week; one remained positive during week 2; and none were positive during week 3. Cocaine and EME were detectable within 2 h; benzoylecgonine was not detected until 4-8 h after low doses and slightly sooner after high doses. The majority of drug was excreted within 24 h. Over 70% of weekly patches worn during low doses were positive for cocaine (≥25 ng/patch), increasing to 100% during high doses. Conclusion: Sweat testing is an effective and reliable method of monitoring cocaine exposure.

Original languageEnglish (US)
Pages (from-to)2085-2094
Number of pages10
JournalClinical chemistry
Issue number11
StatePublished - Nov 2005
Externally publishedYes

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Biochemistry, medical


Dive into the research topics of 'Disposition of cocaine and its metabolites in human sweat after controlled cocaine administration'. Together they form a unique fingerprint.

Cite this