Cocaine disrupts dopamine (DA) and kappa opioid receptor (KOR) system activity, with long-term exposure reducing inhibiton of DA uptake by cocaine and increasing KOR system function. Single treatment therapies have not been successful for cocaine use disorder; therefore, this study focuses on a combination therapy targeting the dopamine transporter (DAT) and KOR. Sprague Dawley rats self-administered 5 days of cocaine (1.5 mg/kg/inf, max 40 inf/day, FR1), followed by 14 days on a progressive ratio (PR) schedule (0.19 mg/kg/infusion). Behavioral effects of individual and combined administration of phenmetrazine and nBNI were then examined using PR. Additionally, ex vivo fast scan cyclic voltammetry was then used to assess alterations in DA and KOR system activity in the nucleus accumbens before and after treatments. Chronic administration of phenmetrazine as well as the combination of phenmetrazine and nBNI-but not nBNI alone-significantly reduced PR breakpoints. In addition, the combination of phenmetrazine and nBNI partially reversed cocaine-induced neurodysregulations of the KOR and DA systems, indicating therapeutic benefits of targeting the DA and KOR systems in tandem. These data highlight the potential benefits of the DAT and KOR as dual-cellular targets to reduce motivation to administer cocaine and reverse cocaine-induced alterations of the DA system.

New psychoactive substances (NPS) are a type of abused drug designed to mimic the effects of the currently known illicit drugs, whose structures are constantly changing to escape surveillance. The quick identification of NPS use in the community therefore demands immediate action. This study aimed to develop a target and suspect screening method using LC-HRMS to identify NPS in wastewater samples. An in-house database of 95 traditional and NPS was built using the reference standards, and an analytical method was developed. Wastewater samples were collected from 29 wastewater treatment plants (WWTP) across South Korea, representing 50 % of the total population. The psychoactive substances in waste water samples were screened using in-house database and developed analytical methods. A total of 14 substances were detected in the target analysis, including three NPS (N-methyl-2-AI, 25E-NBOMe, and 25D-NBOMe) and 11 traditional psychoactive substances and their metabolites (zolpidem phenyl-4-COOH, ephedrine, ritalinic acid, tramadol, phenmetrazine, phendimetrazine, phentermine, methamphetamine, codeine, morphine, and ketamine). Out of these, N-methyl-2-AI, zolpidem phenyl-4-COOH, ephedrine, ritalinic acid, tramadol, phenmetrazine, and phendimetrazine were detected with a detection frequency of over 50 %. Primarily, N-methyl-2-Al was detected in all the wastewater samples. Additionally, four NPSs (amphetamine-N-propyl, benzydamine, isoethcathinone, methoxyphenamine) were tentatively identified at level 2b in a suspect screening analysis. This is the most comprehensive study to investigate NPS using target and suspect analysis methods at the national level. This study raises a need for continuous monitoring of NPS in South Korea.

The organ distribution of 3-fluorophenmetrazine (3-FPM), pyrazolam, diclazepam as well as its main metabolites delorazepam, lormetazepam and lorazepam, was investigated. A solid phase extraction (SPE) and a QuEChERS (acronym for quick, easy, cheap, effective, rugged and safe) - approach were used for the extraction of the analytes from human tissues, body fluids and stomach contents. The detection was performed on a liquid chromatography-tandem mass spectrometry system (LCMS/MS). The analytes of interest were detected in all body fluids and tissues. Results showed femoral blood concentrations of 10 μg/L for 3-FPM, 28 μg/L for pyrazolam, 1 μg/L for diclazepam, 100 μg/L for delorazepam, 6 μg/L for lormetazepam, and 22 μg/L for lorazepam. Tissues (muscle, kidney and liver) and bile exhibited higher concentrations of the mentioned analytes than in blood. Additional positive findings in femoral blood were for 2-fluoroamphetamine (2-FA, approx. 89 μg/L), 2-flourometamphetamine (2-FMA, hint), methiopropamine (approx. 2.2 μg/L), amphetamine (approx. 21 μg/L) and caffeine (positive). Delorazepam showed the highest ratio of heart (C) and femoral blood (P) concentration (C/P ratio = 2.5), supported by the concentrations detected in psoas muscle (430 μg/kg) and stomach content (approx. 210 μg/L, absolute 84 μg). The C/P ratio indicates that delorazepam displays susceptibility for post-mortem redistribution (PMR), supported by the findings in muscle tissue. 3-FPM, pyrazolam, diclazepam, lorazepam and lormetazepam did apparently not exhibit any PMR. The cause of death, in conjunction with autopsy findings was concluded as a positional asphyxia promoted by poly-drug intoxication by arising from designer benzodiazepines and the presence of synthetic stimulants.

A variety of hallucinogens of the lysergamide type has emerged on the drug market in recent years and one such uncontrolled derivative of lysergic acid diethylamide (LSD) is 1-propionyl-LSD (1P-LSD). Due to the high potency of LSD and some of its derivatives (common doses: 50-200 μg), sensitive methods are required for the analysis of biological samples such as serum and urine. The occurrence of an intoxication case required the development of a fully validated, highly sensitive method for the quantification of 1P-LSD and LSD in urine and serum using LC-MS/MS. Given that LSD is unstable in biological samples when exposed to light or elevated temperatures, we also conducted stability tests for 1P-LSD in urine and serum under different storage conditions. The validation results revealed that the analysis method was accurate and precise with good linearity over a wide calibration range (0.015-0.4 ng mL-1). The limit of detection (LOD) and the lower limit of quantification (LLOQ) of 1P-LSD and LSD in serum and urine were 0.005 ng mL-1 and 0.015 ng mL-1, respectively. The stability tests showed no major degradation of 1P-LSD in urine and serum stored at -20 °C, 5 °C or at room temperature for up to five days, regardless of protection from light. However, LSD was detected in all samples stored at room temperature showing a temperature-dependent hydrolysis of 1P-LSD to LSD to some extent (up to 21% in serum). Serum samples were particularly prone to hydrolysis possibly due to enzymatically catalyzed reactions. The addition of sodium fluoride prevented the enzymatic formation of LSD. The method was applied to samples obtained from the intoxication case involving 1P-LSD. The analysis uncovered 0.51 ng mL-1 LSD in urine and 3.4 ng mL-1 LSD in serum, whereas 1P-LSD remained undetected. So far pharmacokinetic data of 1P-LSD is missing, but with respect to the results of our stability tests and the investigated case rapid hydrolysis to LSD in-vivo seems more likely than instabilities of 1P-LSD in urine and serum samples.

Phenmetrazine, a selective dopamine and norepinephrine releaser, previously available as an oral anorectic, is prone to be abused. This study aimed to assess the feasibility of delivering phenmetrazine via the transdermal route for a new indication, while also minimizing its abuse potential. The passive permeation of phenmetrazine through dermatomed human cadaver skin was evaluated using static Franz diffusion cells at 10 mg/mL for the fumarate salt, and at 20, 40, and 80 mg/mL for the free base in propylene glycol for 24 h. Further, oleic acid (5% w/w), oleyl alcohol (5% and 10% w/w), and lauric acid (10% w/w) were investigated as chemical permeation enhancers to enhance the delivery. Skin irritation potential was assessed using EpiDerm™ in vitro reconstructed human epidermal model. The free base showed superior 24-h delivery (8.13 ± 4.07%, 10.6 ± 2.5%, and 10.4 ± 1.4% for groups with 20, 40, and 80 mg/mL of the free base, respectively) to phenmetrazine fumarate salt (undetectable). The successful screening of effective chemical enhancers, oleyl alcohol (5% and 10% w/w), oleic acid (5% w/w), and lauric acid (10% w/w) resulted in significant enhancement of delivery. The calculated therapeutic relevant flux for the potential indication, attention deficit hyperactivity disorder, 20 μg/cm2/h was met, where a 24-mg daily dose from a 50-cm2 patch was projected to be delivered to a 60-kg individual. Irritation study results suggest that formulations with therapeutically relevant delivery are likely to be non-irritant. In conclusion, it is feasible to deliver therapeutically relevant amounts of phenmetrazine via the transdermal route.

Pharmaceutical research not only provides the basis for the development of new medicinal products but also for the synthesis of new drugs of abuse. 3-Fluorophenmetrazine (3-FPM), a fluorinated derivative of the anorectic phenmetrazine, was first patented in 2011 and appeared on the drug market in 2014. Though invented for potential medical purposes, pharmacokinetic data on this compound, crucial for interpreting forensic as well as clinical cases, are not available. Therefore, a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the detection of 3-FPM in serum, urine, and oral fluid was developed, validated for urine and serum, and used to quantify 3-FPM in samples obtained during a controlled self-experiment. The method proved to be linear, selective and sufficiently sensitive. The limits of detection (LODs) were 0.1 ng/mL, 0.2 ng/mL, and 0.05 ng/mL in serum, urine, and oral fluid. Inter-day precision and intra-day precision (RSD) in serum samples were below 6.3% and below 8.5%, respectively. The highest serum concentration (cmax ) of 210 ng/mL was reached 2.5 hours (tmax ) after ingestion. The elimination half-life and the volume of distribution were calculated to be approx. 8.8 hours and 400 L (5.3 L/kg). 3-FPM could be detected in serum and urine up to 82 hours and 116 hours, respectively. It was still detected in the last oral fluid sample taken 55 hours after ingestion. 3-FPM was mainly excreted unchanged. Main metabolic reactions were aryl-hydroxylation and N-hydroxylation. Interestingly, the product of oxidative ring opening (2-amino-1-(3-fluorophenyl)propan-1-ol) showed the largest window of detection in the self-experiment.

Though illegal in the UK, in many countries novel psychoactive substances are quasi-legal synthetic compounds that are widely available online under the guise of research chemicals. These substances are relatively cheap and are often undetectable in standard drug screens. Nearly 200 such compounds are introduced yearly, and little is usually known about their metabolism or physiological effects. Consequently, managing patients in overdose situations on largely unknown substances usually involves supportive care, however anticipating and managing atypical side effects are challenging in the absence of knowledge of these compounds. In this report, we discuss our encounter with a 33-year-old unconscious man presenting with coingestion of a novel stimulant 3-fluorophenmetrazine with a rarely used benzodiazepine etizolam. This patient developed seizure-like activity and delayed widespread T-wave inversions, both of which ultimately resolved without sequelae.

The availability of new psychoactive substances (NPS) on the recreational drug market continues to create challenges for scientists in the forensic, clinical and toxicology fields. Phenmetrazine (3-methyl-2-phenylmorpholine) and an array of its analogs form a class of psychostimulants that are well documented in the patent and scientific literature. The present study reports on two phenmetrazine analogs that have been encountered on the NPS market following the introduction of 3-fluorophenmetrazine (3-FPM), namely 4-methylphenmetrazine (4-MPM), and 3-methylphenmetrazine (3-MPM). This study describes the syntheses, analytical characterization, and pharmacological evaluation of the positional isomers of MPM. Analytical characterizations employed various chromatographic, spectroscopic, and mass spectrometric platforms. Pharmacological studies were conducted to assess whether MPM isomers might display stimulant-like effects similar to the parent compound phenmetrazine. The isomers were tested for their ability to inhibit uptake or stimulate release of tritiated substrates at dopamine, norepinephrine and serotonin transporters using in vitro transporter assays in rat brain synaptosomes. The analytical characterization of three vendor samples revealed the presence of 4-MPM in two of the samples and 3-MPM in the third sample, which agreed with the product label. The pharmacological findings suggest that 2-MPM and 3-MPM will exhibit stimulant properties similar to the parent compound phenmetrazine, whereas 4-MPM may display entactogen properties more similar to 3,4-methylenedioxymethamphetamine (MDMA). The combination of test purchases, analytical characterization, targeted organic synthesis, and pharmacological evaluation of NPS and their isomers is an effective approach for the provision of data on these substances as they emerge in the marketplace.

A variety of new psychoactive substances (NPS) are appearing in recreational drug markets worldwide. NPS are compounds that target various receptors and transporters in the central nervous system to achieve their psychoactive effects. Chemical modifications of existing drugs can generate NPS that are not controlled by current legislation, thereby providing legal alternatives to controlled substances such as cocaine or amphetamine. Recently, 3-fluorophenmetrazine (3-FPM), a derivative of the anorectic compound phenmetrazine, appeared on the recreational drug market and adverse clinical effects have been reported. Phenmetrazine is known to elevate extracellular monoamine concentrations by an amphetamine-like mechanism. Here we tested 3-FPM and its positional isomers, 2-FPM and 4-FPM, for their abilities to interact with plasma membrane monoamine transporters for dopamine (DAT), norepinephrine (NET) and serotonin (SERT). We found that 2-, 3- and 4-FPM inhibit uptake mediated by DAT and NET in HEK293 cells with potencies comparable to cocaine (IC50 values < 2.5 μM), but display less potent effects at SERT (IC50 values >80 μM). Experiments directed at identifying transporter-mediated reverse transport revealed that FPM isomers induce efflux via DAT, NET and SERT in HEK293 cells, and this effect is augmented by the Na+/H+ ionophore monensin. Each FPM evoked concentration-dependent release of monoamines from rat brain synaptosomes. Hence, this study reports for the first time the mode of action for 2-, 3- and 4-FPM and identifies these NPS as monoamine releasers with marked potency at catecholamine transporters implicated in abuse and addiction. This article is part of the Special Issue entitled \'Designer Drugs and Legal Highs.\'

3-Fluorophenmetrazine (3-FPM) is a stimulant-like novel psychoactive substance (NPS) and fluorinated analog of phenmetrazine that has recently appeared on the recreational drug market, with limited published information. Likewise, the synthetic opioid U-47700 has gained popularity among recreational drug users and is frequently detected in postmortem casework. We present the case history, autopsy and toxicological findings of a fatality involving the designer drugs 3-FPM and U-47700 for the first time in the literature. A sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of 3-FPM in whole blood, with a 0.001-0.100 mg/L analytical range. The method met the requirements for acceptable linearity, bias and precision. 3-FPM was detected along with U-47700 and other drugs including amitriptyline, nortriptyline, methamphetamine, amphetamine, diazepam, nordiazepam, temazepam, and the designer benzodiazepines flubromazolam and delorazepam. 3-FPM was quantified in the decedent\'s peripheral (femoral) and central (aortic) blood at 2.4 and 2.6 mg/L, respectively. These concentrations are similar to reported concentrations in non-fatal intoxications. U-47700 was present in peripheral blood at a semi-quantitative concentration of 0.36 mg/L, consistent with reported U-47700 postmortem concentrations. The cause of death was considered multiple drug-toxicity (3-FPM, U-47700, amitriptyline, methamphetamine, diazepam, temazepam, flubromazolam and delorazepam) and the manner of death ruled an accident. This case illustrates the dangers of polysubstance use and discusses the potential overlap between recreational and fatal concentrations for some NPS.