Temporal indication of marijuana use

According to WADA rules the use of cannabinoids is forbidden in competition. In doping control the detection of cannabinoid misuse is based upon detection of the pharmacologically inactive metabolite 11-nor-delta 9-carboxy-tetrahydrocannabinol-9- carboxylic acid (carboxy-THC) in urine. No accurate prediction of the application time is possible because carboxy-THC has a half-life of 6 days. Consequently the adverse finding of carboxy-THC in doping control urine samples collected in competition may probably result from cannabis use out of competition. Because of its shorter half-life the analysis of the pharmacologically active metabolite 11-hydroxy-delta 9-tetrahydrocannabinol (11-hydroxy-THC) may be of interest for the detection of cannabis misuse in competition. Doping control urine samples from national and international federations which have been reported as adverse analytical findings for cannabis in 2005 and 2006 were additionally analysed by gas chromatography/mass spectrometry (GC/MS) for the presence of 11-hydroxy-THC. In 2006 three urine samples showed carboxy-THC concentrations greater than 100 ng/mL and additionally 11-hydroxy-THC levels higher than 3 ng/mL (suggested cut off level in literature for temporal indication of cannabis use). In 2005 twelve specimens showed carboxy-THC values higher than 100 ng/mL. Only two samples contained 11-hydroxy-THC at concentrations greater than 3 ng/mL. This result may depend on storage conditions and degradation of the analyte. Controlled urinary cannabinoid excretion studies are needed to substantiate the suggested cut-off level of 3 ng/mL or to determine an adequate cut-off level for 11-hydroxy-THC in sports drug testing. Verf.-Referat