Method validation and preliminary pharmacokinetic studies on the new designer stimulant 3-fluorophenmetrazine (3-FPM).

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.

Multiple Drug-Toxicity Involving Novel Psychoactive Substances, 3-Fluorophenmetrazine and U-47700.

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.

Adverse events related to the new psychoactive substance 3-fluorophenmetrazine - results from the Swedish STRIDA project.

BACKGROUND: New psychoactive substances (NPS) are often poorly pharmacologically documented and the production is unregulated, implying high risks for toxic side effects. This report from the STRIDA project describes analytically confirmed non-fatal intoxications involving the phenmetrazine analogue 3-fluorophenmetrazine (3-FPM). STUDY DESIGN AND METHODS: Observational case series of patients with suspected acute NPS exposure requiring hospital care. Blood and urine samples were collected from patients presenting in emergency departments (ED) or intensive care units (ICU), after consultation with the Swedish Poisons Information Centre (PIC). Laboratory analysis was performed by multi-component liquid chromatography-mass spectrometry. Clinical data were collected during PIC consultations and retrieved from medical records. RESULTS: From November 2014 to October 2015, eight cases were registered as 3-FPM or "phenmetrazine" intoxications at the PIC after consultation. During the same period, analysis of STRIDA project samples confirmed 3-FPM use in a total of 19 patients (84% men) aged 22-54 (median 30) years. 3-FPM was detected in 15 out of 19 serum (2.7-1416 ng/mL) and in 14 out of 14 urine (1.0-6857 µg/mmol creatinine) samples. All patients were also tested positive for other psychoactive substances, with benzodiazepines being most common (57% of the cases). Ten patients were monitored in the ED for <4 h, while six needed ICU monitoring of which five were graded as severe intoxications (Poisoning Severity Score 3). Prominent clinical signs were tachycardia (47%), depressed consciousness (42%), agitation/anxiety (37%), delirium (37%), dilated pupils (26%), and seizures (16%). All patients survived. CONCLUSION: In 19 patients testing positive for 3-FPM, a high incidence of severe clinical features was demonstrated. However, as all patients had also used other psychoactive substances, it was difficult to identify a unique toxidrome for 3-FPM. The results further showed that many 3-FPM intoxications would have been missed, if relying solely on information from PIC consultations. These results emphasize the importance of performing bioanalytical investigation in cases of suspected NPS intoxication.

Role of phenmetrazine as an active metabolite of phendimetrazine: evidence from studies of drug discrimination and pharmacokinetics in rhesus monkeys.

BACKGROUND: Monoamine releasers such as d-amphetamine that selectively promote release of dopamine/norepinephrine versus serotonin are one class of candidate medications for treating cocaine dependence; however, their clinical utility is limited by undesirable effects such as abuse liability. Clinical utility of these compounds may be increased by development of prodrugs to reduce abuse potential by slowing onset of drug effects. This study examined the behavioral and pharmacokinetic profile of the Schedule III compound phendimetrazine, which may serve as a prodrug for the N-demethylated metabolite and potent dopamine/norepinephrine releaser phenmetrazine. METHODS: Monkeys (n = 5) were trained in a two-key food-reinforced discrimination procedure to discriminate cocaine (0.32 mg/kg, IM) from saline, and the potency and time course of cocaine-like discriminative stimulus effects were determined for (+)-phenmetrazine, (-)-phenmetrazine, (+)-phendimetrazine, (-)-phendimetrazine, and (±)-phendimetrazine. Parallel pharmacokinetic studies in the same monkeys examined plasma phenmetrazine and phendimetrazine levels for correlation with cocaine-like discriminative stimulus effects. RESULTS: Both isomers of phenmetrazine, and the racemate and both isomers of phendimetrazine, produced dose- and time-dependent substitution for the discriminative stimulus effects of cocaine, with greater potency residing in the (+) isomers. In general, plasma phenmetrazine levels increased to similar levels after administration of behaviorally active doses of either phenmetrazine or phendimetrazine. CONCLUSIONS: These results support the hypothesis that phenmetrazine is an active metabolite that contributes to the effects of phendimetrazine. However, behavioral effects of phendimetrazine had a more rapid onset than would have been predicted by phenmetrazine levels alone, suggesting that other mechanisms may also contribute.

Simultaneous determination of morazone and phenmetrazine in rat plasma and urine using an on-column injection technique with fused-silica capillary column gas chromatography.

The simultaneous determination of morazone and its major metabolite, phenmetrazine, using an on-column injection technique with fused-silica capillary column gas chromatography is described. The on-column injection technique prevents the decomposition of morazone. The limit of quantitation in 0.1 mL of rat plasma for morazone and phenmetrazine is 5 ng/mL and that in 1.0 mL of rat urine is 1 ng/mL. The within run precisions (%CV) at the concentration of 0.5 micrograms/mL are 3.27% for morazone and 3.09% for phenmetrazine.