Urinary elimination of 11-nor-9-carboxy-delta9-tetrahydrocannnabinol in cannabis users during continuously monitored abstinence

The time course of 11-nor-9-carboxy-Delta9-tetrahydrocannnabinol (THCCOOH) elimination in urine was characterized in 60 cannabis users during 24 h monitored abstinence on a closed research unit for up to 30 days. Six thousand, one hundred fifty-eight individual urine specimens were screened by immun...

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Bibliographic Details
Published in:Journal of analytical toxicology 2008-10, Vol.32 (8), p.562
Main Authors: Goodwin, Robert S, Darwin, William D, Chiang, C Nora, Shih, Ming, Li, Shou-Hua, Huestis, Marilyn A
Format: Article
Language:English
Subjects:
Adult
Dronabinol - analogs & derivatives
Dronabinol - urine
Female
Humans
Male
Marijuana Abuse - diagnosis
Marijuana Abuse - urine
Substance Abuse Detection - methods
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Summary:The time course of 11-nor-9-carboxy-Delta9-tetrahydrocannnabinol (THCCOOH) elimination in urine was characterized in 60 cannabis users during 24 h monitored abstinence on a closed research unit for up to 30 days. Six thousand, one hundred fifty-eight individual urine specimens were screened by immunoassay with values > or = 50 ng/mL classified as positive. Urine specimens were confirmed for THCCOOH by gas chromatography-mass spectrometry following base hydrolysis and liquid-liquid or solid-phase extraction. In 60%, the maximum creatinine normalized concentration occurred in the first urine specimen; in 40%, peaks occurred as long as 2.9 days after admission. Data were divided into three groups, 0-50, 51-150, and > 150 ng/mg, based on the creatinine corrected initial THCCOOH concentration. There were statistically significant correlations between groups and number of days until first negative and last positive urine specimens; mean number of days were 0.6 and 4.3, 3.2 and 9.7, and 4.7 and 15.4 days, respectively, for the three groups. These data provide guidelines for interpreting urine cannabinoid test results and suggest appropriate detection windows for differentiating new cannabis use from residual drug excretion.
ISSN:0146-4760