Levamisole-Adulterated Cocaine: What about in European Countries?

Recent studies indicate that not only the anthelminthic levamisole but also the racemate tetramisole (R-/S-phenyltetraimidazothiazole, PTHIT) was found as an adulterant for cocaine. We herein report on the investigation of the prevalence of PTHIT among cocaine-positive hair samples and the discrimination of the presence of its stereoisomers levamisole and dexamisole. Cocaine-positive hair samples were collected in a forensic context in 2015 and mainly 2017 (n = 724). Cocaine and PTHIT concentrations have been determined by achiral liquid chromatography-tandem mass spectrometry (LC-MS/MS). For distinction of levamisole/dexamisole chiral LC-MS/MS was performed. Cocaine hair concentrations ranged from 500 (cut-off) to approximately 800 000 pg/mg. The study demonstrates a strong prevalence of PTHIT in cocaine users' hair (87%, n = 627). PTHIT hair concentrations ranged from below LLOQ 3.5 to approximately 61 000 pg/mg (median: 260 pg/mg). Surprisingly, enantiomeric ratios of levamisole/dexamisole ranged from 0.17 to 1.34 (median: 0.63). Therefore, PTHIT-adulterated street cocaine samples (n = 24) seized between 2013 and 2016 were tested. Samples mainly contained racemic tetramisole (87.5%), only one sample contained levamisole only and two samples contained non-racemic PTHIT.Our experiments suggest that the presence of tetramisole in biological samples may have hitherto been underestimated. Most probably higher dexamisole than levamisole concentrations in hair specimens arise from stereoselective metabolism and/or elimination. This is particularly important in light of the different pharmacological activities of the two enantiomers and potentially different adverse effects. Toxicological interpretations in intoxication cases with adulterated cocaine should not only consider levamisole but also tetramisole and terminology in scientific contributions should be used accordingly.

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confidence: 99%

“…1,[6][7][8][9] One pharmacological rationale for the addition of levamisole is that it may have cocaine-like action by inhibition of noradrenaline uptake. 1,[6][7][8][9] However, a recent study from Austria, reports on a decreasing trend in 2017 compared to 2015 and 2016. 1,[6][7][8][9] However, a recent study from Austria, reports on a decreasing trend in 2017 compared to 2015 and 2016.…”

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confidence: 99%

Cocaine adulteration with the anthelminthic tetramisole (levamisole/dexamisole): Long‐term monitoring of its intake by chiral LC–MS/MS analysis of cocaine‐positive hair samples

Madry

Kræmer

Baumgartner

2018

“…Typically, cocaine seizures are already cut with levamisole when entering Belgium and the average amount of levamisole ranges between 5 and 25 w% for 95% of the samples. Levamisole is not an innocent cutting agent; the use of levamisole‐laced cocaine is associated with medical harm . Moreover, the biotransformation product of levamisole – aminorex – has psychoactive and severe side effects, potentially adding to the cocaine's effects …”

Section: Introductionmentioning

confidence: 99%

“…In addition to the identification of controlled substances like cocaine, the degree of purity is often requested for law‐enforcement purposes. Levamisole is not routinely identified and is rarely quantified by forensic laboratories …”

Section: Introductionmentioning

confidence: 99%

“…Levamisole is not an innocent cutting agent; the use of levamisole-laced cocaine is associated with medical harm. [1][2][3][4][5] Moreover, the biotransformation product of levamisoleaminorexhas psychoactive and severe side effects, potentially adding to the cocaine's effects. 3,5 In addition to the identification of controlled substances like cocaine, the degree of purity is often requested for law-enforcement purposes.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Practical tool for sampling and fast analysis of large cocaine seizures

Eliaerts

Meert

Durme

et al. 2018

Large quantities of illicit drugs are frequently seized by law enforcement. In such cases, a representative number of samples needs to be quickly examined prior to destruction. No procedure has yet been set up which rapidly provides information regarding the homogeneity of the samples, the presence of controlled substances, and the degree of purity. This study establishes a protocol for fast analysis of cocaine and its most common cutting agent, levamisole, in large seizures. The protocol is based on a hypergeometric sampling approach combined with Fourier-transform infrared (FTIR) spectrometry and support vector machines (SVM) algorithms as analysis methods. To demonstrate the practical use of this approach, 5 large cocaine seizures (consisting between 45 and 85 units) were analysed simultaneously with gas chromatography-mass spectrometry (GC-MS), gas chromatography-flame ionisation detector (GC-FID), and a portable FTIR spectrometer using attenuated total reflectance (ATR) sampling combined with SVM models. According to the hypergeometric sampling plan of the guidelines of the Drugs Working Group (DWG) of the European Network of Forensic Science Institutes (ENFSI), the required number of subsamples ranged between 19 and 23. Considering the identification analyses, the SVM models detected cocaine and levamisole in all subsamples of Cases 1 to 5 (100% correct classification), which was confirmed by GC-MS analysis. Considering the quantification analyses, the SVM models were able to estimate the cocaine and levamisole content in each subsample, compared to GC-FID data. The developed strategy is easy, cost effective, and provides immediate information about both the presence and concentration of cocaine and levamisole. By using this new strategy, the number of confirmation analyses with laborious and expensive chromatographic techniques could be significantly reduced.

Systematic forensic toxicological analysis by GC‐MS in serum using automated mass spectral deconvolution and identification system

Grapp

Maurer

Desel

2015

Non-targeted screening of body fluids for psychoactive agents is an essential task for forensic toxicology. The challenge is the identification of xenobiotics of interest from background noise and endogenous matrix components. The aim of the present work was to evaluate the use of an Automated Mass Spectral Deconvolution and Identification System (AMDIS) for gas chromatography-mass spectrometry (GC-MS) based toxicological serum screening. One hundred fifty serum samples submitted to the authors´ laboratory for systematic forensic toxicological analysis underwent GC-MS screening after neutral and basic liquid-liquid extraction. Recorded datasets were routinely evaluated both by experienced personnel and automatically using the AMDIS software combined with the Maurer/Pfleger/Weber GC-MS library MPW_2011. The results from manual and automated data evaluation were then systematically compared. AMDIS parameters for data deconvolution and substance identification had been successfully adapted to the GC-MS screening procedure in serum. The number of false positive hits could substantially be reduced without increasing the risk of overlooking relevant compounds. With AMDIS-based data evaluation, additional drugs were identified in 25 samples (17%) that had not been detected by manual data evaluation. Importantly, among these drugs, there were frequently prescribed and toxicologically relevant antidepressants and antipsychotic drugs such as citalopram, mirtazapine, quetiapine, or venlafaxine. For most of the identified drugs, their serum concentrations were in the therapeutic or subtherapeutic range. Thus, our study indicated that automated data evaluation by AMDIS provided reliable screening results. Copyright © 2015 John Wiley & Sons, Ltd.