Challenges in Drug Surveillance: Strengthening the Analysis of New Psychoactive Substances by Harmonizing Drug Checking Services in Proficiency Testing

BACKGROUND

Drug checking is a proven harm reduction strategy and provides real-time information on the market of new psychoactive substances (NPS). It combines chemical analysis of samples with direct engagement with people who use drugs (PWUD), giving the ability to increase preparedness and responsiveness towards NPS. Next to that, it supports rapid identification of potential unwitting consumption. However, NPS cause a toxicological battle for the researchers, as factors such as the unpredictability and quick shift of the market complicate the detection.

METHODS

To evaluate challenges posed towards drug checking services, proficiency testing was set up to evaluate existing analytical techniques and investigate the capability to correctly identify circulating NPS. Twenty blind substances, covering the most common categories of substances, were analyzed according to the existing protocols of the existing drug checking services, including several analytical methods such as gas chromatography-mass spectrometry (GC-MS) and liquid chromatography with diode array detector (LC-DAD).

RESULTS

The proficiency test scores range from 80 to 97.5% accuracy. The most common issues and errors are mainly unidentified compounds, presumably due to no up-to-date libraries, and/ or confusion between structural isomers, such as 3- and 4-chloroethcathinone, or structural analogs, such as MIPLA (N-methyl-N-isopropyl lysergamide) and LSD (D-lysergic acid diethylamide).

CONCLUSIONS

The participating drug checking services have access to adequate analytical tools to provide feedback to drug users and provide up-to-date information on NPS.

A new synthetic cathinone: 3,4-EtPV or 3,4-Pr-PipVP? An unsuccessful attempt to circumvent the German legislation on new psychoactive substances

Synthetic cathinones comprise psychostimulants with desired effects like euphoria, increased vigilance, appetite suppression, and-mainly depending on certain structural features-entactogenic properties. 3,4-EtPV (1-(bicyclo[4.2.0]octa-1,3,5-trien-3-yl)-2-(pyrrolidin-1-yl)pentan-1-one) was first mentioned in an online drug forum in September 2021, where its imminent synthesis was announced. The goal was to produce a legal alternative to the phenylethylamines already banned by the German NpSG. In February and June 2022, two samples labeled with the name and molecular structure of 3,4-EtPV were analyzed. The molecular structure of the obviously mislabeled compound was elucidated and comprehensively characterized within the ADEBAR project. The synthetic cathinone identified differed from the declared 3,4-EtPV by a 3,4-propylene bridge instead of a 3,4-ethylene bridge and a piperidine ring instead of a pyrrolidine ring. The short name 3,4-Pr-PipVP (3,4-propylene-2-(1-piperidinyl)valerophenone) was suggested as a semisystematic name in collaboration with the European Monitoring Centre for Drugs and Drug Addiction. Herein, the results of the analyses are discussed and will enable forensic laboratories to update their databases quickly and identify 3,4-Pr-PipVP confidently. 3,4-Pr-PipVP is already scheduled under the German NpSG. This study highlights that there are ongoing efforts to deliberately circumvent generic definitions given, for example, in the German NpSG and that (unintentional?) mislabeling can be an issue. The end user purchasing substances online can never be sure that the material actually supplied will be the one ordered, and he might receive an illicit drug instead of an uncontrolled one. Furthermore, the purity is always unknown, creating health risks due to unexpected effects and potencies.

Cannabis adulterated with the synthetic cannabinoid receptor agonist MDMB-4en-PINACA and the role of European drug checking services

BACKGROUND

European drug checking services exchange information on drug trends within the Trans European Drug Information (TEDI) network, allowing monitoring and coordination of responses. Starting in Spring 2020, several services detected the synthetic cannabinoid receptor agonist MDMB-4en-PINACA in adulterated low-THC cannabis products.

METHODS

Cannabis products suspected of adulteration were analyzed for the presence of MDMB-4en-PINACA by 9 services in 8 countries within the TEDI network. If available, phytocannabinoid analysis was also performed.

RESULTS

1142 samples sold as cannabis in herbal, resin and e-liquid form were analyzed, of which 270 were found to contain MDMB-4en-PINACA. All cannabis samples contained low THC (<1%), except the e-liquids which contained no phytocannabinoids. Three serious health incidents requiring hospitalization after use of an adulterated cannabis sample were reported.

CONCLUSION

Adulteration of cannabis with synthetic cannabinoid receptor agonists is a new phenomenon that carries risk for people who use it. Given that cannabis consumers are not a usual target group for drug checking services, services and associated harm reduction interventions could be reconfigured to include them.

Acute Limb Ischemia after Intake of the Phenylethylamine Derivate NBOMe

Objective: N-(2-methoxy) benzyl-phenethylamine (NBOMe) derivatives have a high affinity to the serotonin receptor 2A and emerged as new psychedelic agents. We report the case of a 30-year-old man admitted to the hospital because of acute ischemia of the left arm with clinical symptoms of pallor, pulselessness, paresthesia, and a motoric deficit. The patient had a history of schizophrenia and drug abuse and disclosed during the hospital stay the sublingual intake of a substance bought as 25I-NBOMe the night before the ischemic event. Methods: Routine clinical diagnostics including among others color-coded duplex sonography and computed tomography angiography (CTA) were performed. The remainder of the drugs was analyzed using high performance liquid chromatography. Results: Initial color-coded duplex sonography of the upper left limb showed pathological flow profiles of the axillary, brachial, ulnar, and radial artery with a reduced diameter of the ulnar (0.9 mm) and radial (1.1 mm) artery. In consequence, peripheral vasospasm, distal arterial thrombosis, or arterial embolization was anticipated. As therapeutic measures, the patient immediately received intravenous systemic vasodilators (alprostadil) and therapeutic anticoagulation with low molecular weight heparin. Instant symptom improvement was observed within the first day after therapy initiation. The subsequently performed CTA of the heart and left arm showed no signs of thrombotic material. Treatment was continued for five days and the patient was released thereafter having completely normalized perfusion in his left arm. Outpatient treatment was continued with calcium-channel blockers, as the patient had also displayed arterial hypertension. Drug analysis retrieved a composition of the isomers 25I-NBOMe, 25C-NBOMe, and 25H-NBOMe as well as traces of pentylon. Conclusion: NBOMe ingestion implicates the risk of peripheral vasospasms with severe, limb-threatening ischemia.

Application of a Combined Approach to Identify New Psychoactive Street Drugs and Decipher Their Mechanisms at Monoamine Transporters

Psychoactive compounds can cause acute and long-term health problems and lead to addiction. In addition to well-studied and legally controlled compounds like cocaine, new psychoactive substances (NPS) are appearing in street drug markets as replacement strategies and legal alternatives. NPS are effectively marketed as "designer drugs" or "research chemicals" without any knowledge of their underlying pharmacological mode of action and their potential toxicological effects and obviously devoid of any registration process. As of 2016, the knowledge of structure-activity relationships for most NPS is scarce, and predicting detailed pharmacological activity of newly emerging drugs is a challenging task. Therefore, it is important to combine different approaches and employ biological test systems that are superior to mere chemical analysis in recognizing novel and potentially harmful street drugs. In this chapter, we provide a detailed description of techniques to decipher the molecular mechanism of action of NPS that target the high-affinity transporters for dopamine, norepinephrine, and serotonin. In addition, this chapter provides insights into a combined approach to identify and characterize new psychoactive street drugs of unknown content in a collaboration with the Austrian prevention project "checkit!."

Cocaine adulteration

Cocaine is a naturally occurring and illicitly used psychostimulant drug. Cocaine acts at monoaminergic neurotransmitter transporters to block uptake of the monoamines, dopamine, serotonin and norepinephrine. The resulting increase of monoamines in the extracellular space underlies the positively reinforcing effects that cocaine users seek. In turn, this increase in monoamines underlies the development of addiction, and can also result in a number of severe side effects. Currently, cocaine is one of the most common illicit drugs available on the European market. However, cocaine is increasingly sold in impure forms. This trend is driven by cocaine dealers seeking to increase their profit margin by mixing ("cutting") cocaine with numerous other compounds ("adulterants"). Importantly, these undeclared compounds put cocaine consumers at risk, because consumers are not aware of the additional potential threats to their health. This review describes adulterants that have been identified in cocaine sold on the street market. Their typical pharmacological profile and possible reasons why these compounds can be used as cutting agents will be discussed. Since a subset of these adulterants has been found to exert effects similar to cocaine itself, we will discuss levamisole, the most frequently used cocaine cutting agent today, and its metabolite aminorex.

Aminorex, a metabolite of the cocaine adulterant levamisole, exerts amphetamine like actions at monoamine transporters

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We quantified adulterants in street drugs sold as cocaine.

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We analyzed effects of the most common adulterant levamisole, on neurotransmitter transporters.

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Differences in the selectivity of levamisole can be explained by homology modelling and docking.

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Aminorex, a metabolite of levamisole, modulates neurotransmitter transporters directly.

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Depending on the transporter, aminorex acts as a blocker or as a releaser.

Psychostimulants such as amphetamine and cocaine are illicitly used drugs that act on neurotransmitter transporters for dopamine, serotonin or norepinephrine. These drugs can by themselves already cause severe neurotoxicity. However, an additional health threat arises from adulterant substances which are added to the illicit compound without declaration. One of the most frequently added adulterants in street drugs sold as cocaine is the anthelmintic drug levamisole. We tested the effects of levamisole on neurotransmitter transporters heterologously expressed in HEK293 cells. Levamisole was 100 and 300-fold less potent than cocaine in blocking norepinephrine and dopamine uptake, and had only very low affinity for the serotonin transporter. In addition, levamisole did not trigger any appreciable substrate efflux. Because levamisole and cocaine are frequently co-administered, we searched for possible allosteric effects; at 30 μM, a concentration at which levamisole displayed already mild effects on norepinephrine transport it did not enhance the inhibitory action of cocaine. Levamisole is metabolized to aminorex, a formerly marketed anorectic drug, which is classified as an amphetamine-like substance. We examined the uptake-inhibitory and efflux-eliciting properties of aminorex and found it to exert strong effects on all three neurotransmitter transporters in a manner similar to amphetamine. We therefore conclude that while the adulterant levamisole itself has only moderate effects on neurotransmitter transporters, its metabolite aminorex may exert distinct psychostimulant effects by itself. Given that the half-time of levamisole and aminorex exceeds that of cocaine, it may be safe to conclude that after the cocaine effect “fades out” the levamisole/aminorex effect “kicks in”.

A combined approach using transporter-flux assays and mass spectrometry to examine psychostimulant street drugs of unknown content

The illicit consumption of psychoactive compounds may cause short and long-term health problems and addiction. This is also true for amphetamines and cocaine, which target monoamine transporters. In the recent past, an increasing number of new compounds with amphetamine-like structure such as mephedrone or 3,4-methylenedioxypyrovalerone (MDPV) entered the market of illicit drugs. Subtle structural changes circumvent legal restrictions placed on the parent compound. These novel drugs are effectively marketed “designer drugs” (also called “research chemicals”) without any knowledge of the underlying pharmacology, the potential harm or a registration of the manufacturing process. Accordingly new entrants and their byproducts are identified postmarketing by chemical analysis and their pharmacological properties inferred by comparison to compounds of known structure. However, such a heuristic approach fails, if the structures diverge substantially from a known derivative. In addition, the understanding of structure–activity relations is too rudimentary to predict detailed pharmacological activity. Here, we tested a combined approach by examining the composition of street drugs using mass spectrometry and by assessing the functional activity of their constituents at the neuronal transporters for dopamine, serotonin, and norepinephrine. We show that this approach is superior to mere chemical analysis in recognizing novel and potentially harmful street drugs.