Analysis of Cocaine and Its Metabolites in Urine after Consumption of Coca Tea by Five Subjects and Subsequent Hair Testing
Abstract Coca tea is a popular drink in some countries of South America where it is reputed to have medicinal properties. This preparation is composed of natural cocaine (COC) alkaloids and therefore can be banned in some countries. During an anti-doping control in Peru, the urine of an athlete was tested positive for benzoylecgonine (BZE), ecgonine methyl ester (EME) and COC (400, 180 and 0.5 ng/mL, respectively). The athlete indicated that she had consumed coca tea in the morning before the competition. As her lawyer contacted us to assess the scientific aspects of the possible involvement of coca tea to explain the adverse analytical finding, a study was implemented with similar tea bags. Five volunteers from the laboratory consumed 250 mL of coca tea containing approximately 3.8 mg of COC. Eleven urine specimens were collected for each subject for 3 days to follow the elimination of COC and metabolites (BZE and EME). All samples were analyzed by UHPLC-MS/MS (Ultra High Performance Liquid Chromatography - tandem mass spectrometer) after alkaline extraction. Maximum detection times for COC was 20 h, with concentrations ranging from 6 to 91 ng/mL. Maximum detection times for BZE and EME were 70 h and 60 h, respectively, with concentrations ranging from 6 to 3,730 ng/mL and from 6 to 1,738 ng/mL. The concentration profiles were identical for the five volunteers. This study supports the athlete’s claims. In addition, the sample of hair strands of the five subjects was collected a month later and all the hair tests showed a negative result for COC with a limit of decision of 10 pg/mg. Although it is accepted that a 4-mg dose of COC has no significant pharmacological effect, the consummation of coca tea can lead to significant legal consequences since the measured urine concentrations sometimes cannot be considered incidental. Therefore, discrimination between coca tea consummation and recreational COC abuse relies primarily on hair analysis.
