Disposition of cocaine and its metabolites in human sweat after controlled cocaine administration.
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. PharmChek 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 (> or =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 (> or =25 ng/patch), increasing to 100% during high doses.


CONCLUSIONS
Sweat testing is an effective and reliable method of monitoring cocaine exposure.
Kacinko
Sherri L
SL
Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA.
Barnes
Allan J
AJ
Schwilke
Eugene W
EW
Cone
Edward J
EJ
Moolchan
Eric T
ET
Huestis
Marilyn A
MA
D000328:Adult; D003042:Cocaine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000378:metabolism / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D008297:Male; D015813:Substance Abuse Detection; D013542:Sweat / Q000378:metabolism*
C005618:benzoylecgonine; D003042:Cocaine; C034524:ecgonine methyl ester