Synthesis, characterization, and monoamine transporter activity of the new psychoactive substance 3',4'-methylenedioxy-4-methylaminorex (MDMAR).

The recent occurrence of deaths associated with the psychostimulant cis-4,4'-dimethylaminorex (4,4'-DMAR) in Europe indicated the presence of a newly emerged psychoactive substance on the market. Subsequently, the existence of 3,4-methylenedioxy-4-methylaminorex (MDMAR) has come to the authors' attention and this study describes the synthesis of cis- and trans-MDMAR followed by extensive characterization by chromatographic, spectroscopic, mass spectrometric platforms and crystal structure analysis. MDMAR obtained from an online vendor was subsequently identified as predominantly the cis-isomer (90%). Exposure of the cis-isomer to the mobile phase conditions (acetonitrile/water 1:1 with 0.1% formic acid) employed for high performance liquid chromatography analysis showed an artificially induced conversion to the trans-isomer, which was not observed when characterized by gas chromatography. Monoamine release activities of both MDMAR isomers were compared with the non-selective monoamine releasing agent (+)-3,4-methylenedioxymethamphetamine (MDMA) as a standard reference compound. For additional comparison, both cis- and trans-4,4'-DMAR, were assessed under identical conditions. cis-MDMAR, trans-MDMAR, cis-4,4'-DMAR and trans-4,4'-DMAR were more potent than MDMA in their ability to function as efficacious substrate-type releasers at the dopamine (DAT) and norepinephrine (NET) transporters in rat brain tissue. While cis-4,4'-DMAR, cis-MDMAR and trans-MDMAR were fully efficacious releasing agents at the serotonin transporter (SERT), trans-4,4'-DMAR acted as a fully efficacious uptake blocker. Currently, little information is available about the presence of MDMAR on the market but the high potency of ring-substituted methylaminorex analogues at all three monoamine transporters investigated here might be relevant when assessing the potential for serious side-effects after high dose exposure.

Determination of levamisole, aminorex, and pemoline in plasma by means of liquid chromatography-mass spectrometry and application to a pharmacokinetic study of levamisole.

Levamisole is an anti-helminthic drug and gained forensic interest after it was found that it was used as a cocaine adulterant. A liquid chromatography-mass spectrometry (LC-MS) method for the determination of levamisole and its metabolite aminorex in human plasma is described. Selectivity is given; calibration curves were linear within a calibration range of 1 ng/mL-500 ng/mL. Limits of detection and quantification (LODs, LOQs) were 0.85 ng/mL for levamisole and 0.09 ng/mL, and 0.34 ng/mL for aminorex, respectively. Precision data was in accordance with the GTFCh guidelines. The validated method was successfully applied to study the pharmacokinetics of levamisole after administration of 100 mg of levamisole orally. Levamisole could be detected up to 36 h after ingestion in serum, while aminorex never exceeded the LOQ. A one-compartment model best described levamisole pharmacokinetics. The following parameters were calculated: ka = 1.2 [1/h], CL/F = 52 l/h, V/F = 347 l, f (renal) = 0.0005, t ½ = 2.0 h, AUC = 1923 ng/mL*h, cmax = 214 ng/mL, tmax = 1.98 h. Levamisole could be quantified in 42.5% of cocaine--positive plasma samples (2.2 to 224 ng/mL). Aminorex was positive in only 11.3% of the cases; however, it was never found higher than the LOQ. Pemoline, another stimulant detected in horse urine samples after administration of levamisole, was not found either in serum or in urine of this pharmacokinetic study. In post-mortem cases, levamisole and aminorex could be detected in femoral blood and the urine of cocaine users. Pemoline was not detected.

Metabolism of levamisole and kinetics of levamisole and aminorex in urine by means of LC-QTOF-HRMS and LC-QqQ-MS.

The antihelminthic drug Levamisole can enhance cocaine effects by conversion into the amphetamine-like drug aminorex. We describe an LC-MS method for the determination of levamisole and its metabolite aminorex in human urine. Selectivity is given, calibration curves were linear within the calibration range 2.5-250 ng/mL; limits of the method were LoD 0.51 ng/mL, LoQ 1.02 ng/mL for levamisole and LoD 0.65 ng/mL, LoQ 0.76 ng/mL for aminorex. Precision data was in accordance with the guidelines (intraday precision for aminorex ranged between 5.75 and 11.0 % for levamisole between 8.36 and 10.9 %; interday precision for levamisole 10.9-16.9 % and for aminorex 7.64-12.7 %; accuracy data for levamisole -1.96 to -14.3 % and for aminorex-11.9 to-18.5 %). The validated method was successfully applied to study the urinary excretion of levamisole after the administration of 100 mg of levamisole orally. Levamisole and aminorex could be detected in post-administration urine samples. Levamisole could be detected up to 39 h after ingestion, while aminorex was detectable up to 54 h. Maximum aminorex concentrations were 45 ng/mL urine. Further metabolites of levamisole after oral ingestion by means of liquid chromatography hybrid quadrupole time-of-flight high-resolution mass spectrometry (LC-QTOF-HRMS) were identified. Only 0.5 % of the ingested drug was quantified as unchanged levamisole in urine. Besides aminorex, five isomers of aminorex and 4 hydroxy-metabolites of aminorex or its isomers were found. Furthermore, levamisole is also hydroxylated and eliminated free or conjugated with sulfate or glucuronide into urine.

Aminorex poisoning in cocaine abusers.

Levamisole is found in more than 80% of illicit cocaine seized within United States borders. Percentages are somewhat lower in Europe. In 2009, controlled in vivo studies demonstrated that horses metabolize levamisole to aminorex. Earlier this year our laboratory demonstrated that the same conversion occurs in man. Levamisole itself causes aplastic anemia and numerous reports have begun to appear in the literature, but the conversion of levamisole to aminorex is of much more concern. Aminorex ingestion was responsible for a five-year epidemic (1967-1972) of idiopathic pulmonary hypertension (IPH) confined to Switzerland, Austria, and Germany, the only countries where aminorex had been marketed as an anorectic. The incidence of IPH reverted to normal levels as soon as aminorex was withdrawn. In most cases onset of symptoms in IPH began after six to nine months of aminorex use, with average dosage ranges of 10 to 40 mg per day. The outcome was almost uniformly fatal. The conversion rate of levamisole to aminorex has not been established, but given the high daily intake of cocaine by many abusers, it seems likely that many of them will have ingested enough contaminated cocaine to ultimately cause IPH. Until the disease is well established, the symptoms of IHP are vague, and existing drug registries specifically exclude drug abusers, making it difficult to track these cases. This review is intended to draw attention to what may be a slowly emerging new epidemic.

Aminorex, fenfluramine, and chlorphentermine are serotonin transporter substrates. Implications for primary pulmonary hypertension.

BACKGROUND: Coadministration of phentermine and fenfluramine (phen/fen) effectively treats obesity and possibly addictive disorders. The association of fenfluramine and certain other anorexic agents with serious side effects, such as cardiac valvulopathy and primary pulmonary hypertension (PPH), limits the clinical utility of these drugs. Development of new medications that produce neurochemical effects like phen/fen without causing unwanted side effects would be a significant therapeutic breakthrough. METHODS AND RESULTS: We tested the hypothesis that fenfluramine (and other anorexic agents) might increase the risk of PPH through interactions with serotonin (5-HT) transporters. Because 5-HT transporter proteins in the lung and brain are identical, we examined, in rat brain, the effects of selected drugs on 5-HT efflux in vivo and monoamine transporters in vitro as a generalized index of transporter function. Our data show that drugs known or suspected to increase the risk of PPH (eg, aminorex, fenfluramine, and chlorphentermine) are 5-HT transporter substrates, whereas drugs that have not been shown to increase the risk of PPH are less potent in this regard. CONCLUSIONS: We speculate that medications that are 5-HT transporter substrates get translocated into pulmonary cells where, depending on the degree of drug retention, their intrinsic drug toxicity, and individual susceptibility, PPH could develop as a response to high levels of these drugs or metabolites. Emerging evidence suggests that it is possible to develop transporter substrates devoid of adverse side effects. Such medications could have therapeutic application in the management of obesity, drug dependence, depression, and other disorders.

Polymorphic debrisoquine and mephenytoin hydroxylation in patients with pulmonary hypertension of vascular origin after aminorex fumarate.

During the period 1967 to 1971 an increase in the incidence of pulmonary hypertension of vascular origin (PHVO) was observed in Austria, Federal Republic of Germany, and Switzerland. Most patients had been given aminorex fumarate and a possible link was suspected. We therefore investigated the possibility of genetically-determined drug hydroxylation deficiencies (debrisoquine or mephenytoin type) in these patients as an explanation for the development of PHVO. Seventeen patients took 10 mg debrisoquine and 100 mg mephenytoin orally. Sixteen PHVO patients were classified as extensive metabolizers of debrisoquine with logarithmic metabolic ratios of -0.35 +/- 0.11 (mean +/- SEM), whereas one patient was a poor metabolizer with a logarithmic metabolic ratio of 1.82. For the mephenytoin hydroxylation sixteen patients with PHVO were extensive metabolizers, with logarithmic hydroxylation indices of 0.27 +/- 0.05. One poor metabolizer of mephenytoin had a logarithmic hydroxylation index of 1.59. Deficient hydroxylation of debrisoquine and mephenytoin was found in two different patients. The prevalence of poor metabolizers among patients with PHVO after aminorex fumarate was therefore approximately 9% for both debrisoquine and mephenytoin. This corresponds closely to the data of our reference population study where genetic debrisoquine and mephenytoin hydroxylation deficiencies occurred independently, with a prevalence of 10% and 5% respectively. Thus, the normal prevalence of extensive drug hydroxylation phenotypes in patients with PHVO is not consistent with the hypothesis that the development of PHVO after aminorex fumarate might be related to a pharmacogenetically determined impairment of polymorphic drug oxidation.