Citation

Toennes SW, Iwersen-Bergmann S, Kauert GF. Blutalkohol 2007; 44(1): 1-8.

Affiliation

Institut fur Forensische Toxikologie, Zentrum der Rechtsmedizin, 60596 Frankfurt/Main, Germany

Copyright

(Copyright © 2007, International Committee on Alcohol, Drugs and Traffic Safety and Bund gegen Alkohol und Drogen im Straßenverkehr, Publisher Steintor Verlag)

DOI

unavailable

PMID

unavailable

Abstract

Cocaine is an illegal drug of abuse, the use of which leads to impairment of driving performance and psychic control. In Germany, its analytical assay proved to be complicated due to the use of blood sampling devices without stabilizing agents. Cocaine is usually enzymatically degraded to products having no psychotropic activity, which means that time and dosage of recent cocaine use cannot be reliably estimated. However, the product of the degradation process is almost exclusively ecgonine methyl ester (EME), the concentration of which might support the interpretation. In a study on the stability of cocaine, ecgonine methyl ester and benzoylecgonine (BZE) in blood samples it was found that cocaine is almost completely degraded within one day and the concentrations of the resulting EME and the main in-vivo metabolite BZE decline further at a similar rate (half-lives of 5.6 and 7.2 days, respectively). The ratio of EME and BZE is therefore considered to be sufficiently constant. It was found that this ratio is not higher than 10.2% in stabilized blood samples indicating the maximum content of EME as in-vivo metabolite. In 70% of the cases the ratio in the corresponding unstabilized samples was higher. In 395 serum samples of cocaine users a similar proportion of the ratio above 10.2% was found (63%) indicating a high probability of the presence of cocaine in the body at the time of blood sampling.