Identification of metabolites of 3,4-(methylenedioxy)methamphetamine in human urine

Wastewater profiling of illicit drugs, an estimation of community consumption: A case study of eThekwini Metropolitan Municipality, South Africa

Estimation of community-wide consumption of illicit drugs through wastewater analysis is a new concept in Africa although widely applied in developed nations as wastewater-based epidemiology (WBE). It is an important tool that can be used in understanding supply and demand patterns of illicit drug use on a local, national, and international scale. Information on illicit drug use is currently limited in Africa, because of a lack of monitoring structures by governments and financial constraints. This study hopes to bridge that gap by contributing to Africa's baseline information on illicit drug use. This study provides the first application of wastewater analysis to quantitatively evaluate daily illicit drug use in the eThekwini Metropolitan Municipality of KwaZulu-Natal Province of South Africa by quantifying the major urinary excreted metabolites, called drug target residues (DTRs), in raw wastewater from four major wastewater treatment plants (WWTPs) sampled for a week. The results showed that cocaine was the dominant illicit drug consumed in the catchment followed by amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine and 3,4-methylenedioxyamphetamine, with a per capita use of 360-3000 mg day-1 1000 inh-1, 47-800 mg day-1 1000 inh-1, 19-120 mg day -1 1000 inh-1, not detected (ND) to 4.9 mg day-1 1000 inh-1, and ND to 410 g day-1 1000 inh-1 respectively. The weekly usage patterns between the four WWTPs differed probably due to the lifestyle of the populace serving the different WWTPs. These results provide useful data on illicit drug use in eThekwini that can be utilised by public health agencies to implement suitable response strategies.

Ecstasy : la deuxième vague…

La molécule de MDMA (3,4-méthylènedioxyméthamphétamine ou ecstasy) a plus de 100 ans. Sa consommation a explosé dans les années 1990, essentiellement dans un cadre « festif » ou « récréatif ». Elle a ensuite considérablement diminué au début des années 2000 et connaît actuellement un regain d’intérêt certain. Sa consommation a volontiers été considérée comme anodine avant qu’il n’apparaisse clairement qu’elle pouvait provoquer des décès, en l’absence même de « surdose ». Les mécanismes de toxicité sont multiples, complexes et imparfaitement élucidés. L’interaction avec les principaux neuromédiateurs est certaine. L’ecstasy est classée dans les produits empathogènes. Sa consommation vise à favoriser les relations sociales. De nombreux effets secondaires sont possibles. Les conditions de consommation, en ambiance confinée, avec une activité physique soutenue et prolongée favorisent la survenue des effets secondaires. Les effets secondaires bénins sont tolérés et considérés comme étant le « prix à payer » dans la recherche des effets psychogènes. En raison de son tropisme, les principales complications de la consommation d’ecstasy sont psychiatriques et neurologiques, mais aussi cardiovasculaires, respiratoires et métaboliques. Cependant, les formes graves de l’intoxication sont marquées par un tableau d’hyperthermie maligne responsable de complications multiples et pouvant conduire au décès. Tous les auteurs insistent sur la possibilité de complications, de formes graves, voire de décès après la consommation d’une dose unique de MDMA. Il n’y a pas de traitement spécifique. Le traitement symptomatique est au premier plan. Hydratation et sédation sont les clés de ce traitement.

Enantioselective degradation of amphetamine-like environmental micropollutants (amphetamine, methamphetamine, MDMA and MDA) in urban water

This paper aims to understand enantioselective transformation of amphetamine, methamphetamine, MDMA (3,4-methylenedioxy-methamphetamine) and MDA (3,4-methylenedioxyamphetamine) during wastewater treatment and in receiving waters. In order to undertake a comprehensive evaluation of the processes occurring, stereoselective transformation of amphetamine-like compounds was studied, for the first time, in controlled laboratory experiments: receiving water and activated sludge simulating microcosm systems. The results demonstrated that stereoselective degradation, via microbial metabolic processes favouring S-(+)-enantiomer, occurred in all studied amphetamine-based compounds in activated sludge simulating microcosms. R-(-)-enantiomers were not degraded (or their degradation was limited) which proves their more recalcitrant nature. Out of all four amphetamine-like compounds studied, amphetamine was the most susceptible to biodegradation. It was followed by MDMA and methamphetamine. Photochemical processes facilitated degradation of MDMA and methamphetamine but they were not, as expected, stereoselective. Preferential biodegradation of S-(+)-methamphetamine led to the formation of S-(+)-amphetamine. Racemic MDMA was stereoselectively biodegraded by activated sludge which led to its enrichment with R-(-)-enantiomer and formation of S-(+)-MDA. Interestingly, there was only mild stereoselectivity observed during MDMA degradation in rivers. This might be due to different microbial communities utilised during activated sludge treatment and those present in the environment. Kinetic studies confirmed the recalcitrant nature of MDMA.

Toxicity of amphetamines: an update

Amphetamines represent a class of psychotropic compounds, widely abused for their stimulant, euphoric, anorectic, and, in some cases, emphathogenic, entactogenic, and hallucinogenic properties. These compounds derive from the β-phenylethylamine core structure and are kinetically and dynamically characterized by easily crossing the blood-brain barrier, to resist brain biotransformation and to release monoamine neurotransmitters from nerve endings. Although amphetamines are widely acknowledged as synthetic drugs, of which amphetamine, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) are well-known examples, humans have used natural amphetamines for several millenniums, through the consumption of amphetamines produced in plants, namely cathinone (khat), obtained from the plant Catha edulis and ephedrine, obtained from various plants in the genus Ephedra. More recently, a wave of new amphetamines has emerged in the market, mainly constituted of cathinone derivatives, including mephedrone, methylone, methedrone, and buthylone, among others. Although intoxications by amphetamines continue to be common causes of emergency department and hospital admissions, it is frequent to find the sophism that amphetamine derivatives, namely those appearing more recently, are relatively safe. However, human intoxications by these drugs are increasingly being reported, with similar patterns compared to those previously seen with classical amphetamines. That is not surprising, considering the similar structures and mechanisms of action among the different amphetamines, conferring similar toxicokinetic and toxicological profiles to these compounds. The aim of the present review is to give an insight into the pharmacokinetics, general mechanisms of biological and toxicological actions, and the main target organs for the toxicity of amphetamines. Although there is still scarce knowledge from novel amphetamines to draw mechanistic insights, the long-studied classical amphetamines-amphetamine itself, as well as methamphetamine and MDMA, provide plenty of data that may be useful to predict toxicological outcome to improvident abusers and are for that reason the main focus of this review.

Influence of CYP2D6 polymorphism on 3,4-methylenedioxymethamphetamine (‘Ecstasy’) cytotoxicity

OBJECTIVES

Remarkable interindividual differences in 3,4-methylenedioxymethamphetamine ('Ecstasy')-mediated toxicity have been reported in humans. Therefore, we tested whether CYP2D6 or its variant alleles as well as CYP3A4 influence the susceptibility to 3,4-methylenedioxymethamphetamine.

METHODS

3,4-Methylenedioxymethamphetamine cytotoxicity was determined in V79 cells expressing human wild-type CYP2D6 (CYP2D6*1), the low-activity alleles CYP2D6*2, *9, *10, and *17, as well as human CYP3A4. Metabolites of 3,4-methylenedioxymethamphetamine formed by the different cell lines were quantified by high-performance liquid chromatography/electrochemical detector.

RESULTS

Toxicity of 3,4-methylenedioxymethamphetamine was clearly increased in cells expressing CYP2D6*1 compared with the parental cells devoid of CYP-dependent enzymatic activity. Toxicity in V79 CYP2D6*1 cells was also higher than in V79 cell lines expressing the low-activity alleles CYP2D6*2, *9, *10, or *17. In contrast to CYP2D6, the CYP3A4 isoenzyme did not enhance 3,4-methylenedioxymethamphetamine toxicity. Formation of the oxidative 3,4-methylenedioxymethamphetamine metabolite N-methyl-alpha-methyldopamine was greatly enhanced in V79 cell line transfected with CYP2D6*1 compared to all other cell lines. The increase in the cytotoxic effects of 3,4-methylenedioxymethamphetamine observed in this cell line was therefore suspected to be a consequence of the production of this metabolite. This was further investigated by testing the cytotoxicity of N-methyl-alpha-methyldopamine to the control cell line. The results confirmed our hypothesis as the metabolite proved to be more than 100-fold more toxic than the parent compound 3,4-methylenedioxymethamphetamine.

CONCLUSIONS

CYP2D6*1 mediates 3,4-methylenedioxymethamphetamine toxicity via formation of N-methyl-alpha-methyldopamine. Therefore, it will be important to investigate whether CYP2D6 ultrarapid metabolizers are overrepresented in the cases of 3,4-methylenedioxymethamphetamine intoxications.

The designer drug situation in Ibiza

A total of 137 urine samples and 46 serum samples, corresponding to 154 self-confessed designer drugs consumers in Ibiza island, were analyzed for the presence of designer drugs: amphetamine and amphetamine derivatives (methamphetamine, methylenedioxymethamphetamine (MDMA), methylenedioxyethylamphetamine (MDEA), methylenedioxyamphetamine (MDA), p-methoxymethylamphetamine (PMMA), p-methoxyamphetamine (PMA), etc.), ketamine and gamma-hydroxybutyric acid. Among this population, coming both from the forensic clinic and from the emergency room of a hospital, a total of 99 cases were found positive for some designer drug. This study shows the prevalence of methylenedioxymethamphetamine (MDMA) among designer drug users, sole or in association with other drugs. Also, the mixture of MDMA with other designer drugs, ethanol and/or cocaine is shown to be more likely to produce toxic symptoms requiring clinical attendance in a hospital emergency room. These findings along with the consumption history, the concentrations of drugs and metabolites in urine and serum and the toxicological significance for the interpretation of some MDMA metabolites such as 4-hydroxy-3-methoxymethamphetamine (HMMA) are discussed in this study.

Stereochemical analysis of 3,4-methylenedioxymethamphetamine and its main metabolites by gas chromatography/mass spectrometry

3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is consumed as the racemate but some metabolic steps are enantioselective. In addition, chiral properties are preserved during MDMA biotransformation. A quantitative analytical methodology using gas chromatography/mass spectrometry (GC/MS) to determine enantioselective disposition in the body of MDMA and its main metabolites including 3,4-methylenedioxyamphetamine (MDA), 4-hydroxy-3-methoxymethamphetamine (HMMA), and 4-hydroxy-3-methoxyamphetamine (HMA) was developed. Plasma and urine samples were collected from a male volunteer. The analysis of MDMA, MDA, and 4-hydroxy-3-methoxy metabolites by GC/MS required a two-step derivatization procedure. The first step consisted of derivatization of the amine with enantiomerically pure Mosher's reagent ((R)-MTPCl). Triethylamine was used as a base to neutralize hydrochloric acid formed during the reaction allowing quantitative derivatization, which resulted in a substantial improvement in the sensitivity of the method compared with other previously described techniques. Further treatment with ammonium hydroxide was required since both amine and hydroxyl groups underwent derivatization in the reaction. Ammonium hydroxide breaks bonds formed with hydroxyl groups without affecting amine derivatives. The second derivatization step using hexamethyldisilazane was needed for metabolites containing phenol residues. This derivatization method permitted the stereochemically specific study of MDMA and its main monohydroxylated metabolites by GC/MS. A detailed study of the chemical reactions involved in the derivatization steps was indispensable to develop a straightforward, sensitive, and reproducible method for the analysis of the parent drug compound and its metabolites.

Reduced (+/-)-3,4-methylenedioxymethamphetamine ("Ecstasy") metabolism with cytochrome P450 2D6 inhibitors and pharmacogenetic variants in vitro

"Ecstasy" [(+/-)-3,4-methylenedioxymethamphetamine or MDMA] is a CNS stimulant, whose use is increasing despite evidence of long-term neurotoxicity. In vitro, the majority of MDMA is demethylenated to (+/-)-3,4-dihydroxymethamphetamine (DHMA) by the polymorphic cytochrome P450 2D6 (CYP2D6). We investigated the demethylenation of MDMA and dextromethorphan (DEX), as a comparison drug, in reconstituted microsomes expressing the variant CYP2D6 alleles (*)2, (*)10, and (*)17, all of which have been linked to decreased enzyme activity. With MDMA, intrinsic clearances (V(max)/K(m)) in CYP2D6.2, CYP2D6.17, and CYP2D6.10 were reduced 15-, 13-, and 135-fold, respectively, compared with wild-type CYP2D6.1. With DEX, intrinsic clearances were reduced by 37-, 51-, and 164-fold, respectively. It was evident that CYP2D6.17 displayed substrate-specific changes in drug affinity (K(m)). Compounds potentially used with MDMA [fluoxetine, paroxetine, (-)-cocaine] demonstrated significant inhibition of MDMA metabolism in both human liver and CYP2D6.1-expressing microsomes. These data demonstrate that individuals possessing the CYP2D6(*)2, (*)17, and, particularly, (*)10 alleles may show significantly reduced MDMA metabolism. These individuals, and those taking CYP2D6 inhibitors, may demonstrate altered acute and/or long-term MDMA-related toxicity.

Action of MDMA (ecstasy) and its metabolites on arginine vasopressin release

3,4-Methylenedioxymethamphetamine (MDMA) has been reported to cause hyponatraemia, which appears to result from inappropriate secretion of the antidiuretic hormone arginine vasopressin (AVP). After administration of a low dose of (R,S)-MDMA (40 mg) to eight healthy drug-free male volunteers, concentrations of AVP in plasma increased significantly at 1, 2, and 4 hours. Although no relation between plasma MDMA and AVP was found on an examination of the entire data set over the 24-hour study period, a statistically significant negative correlation was observed at 1 hour. As this occurred at a time when both AVP and MDMA concentrations were rising, it was postulated that a metabolite, or metabolites, could primarily be responsible for the increase in AVP. To test this hypothesis we examined the effect of MDMA and five of its metabolites, in the dose range 0.1-1,000 nM, on AVP release from the isolated rat hypothalamus. All compounds tested were found to increase AVP release (using 10 nM and 1,000 nM concentrations), with 4-hydroxy-3-methoxymethamphetamine (HMMA), the major metabolite of MDMA, being the most potent, and 3,4-dihydroxymethamphetamine (DHMA) the least potent. Each compound (1,000 nM), with the exception of DHMA, also enhanced the response to 40-mM potassium stimulation. Our findings confirm that metabolites of MDMA, in addition to the parent drug, contribute to AVP secretion in vitro. Further work will demonstrate whether this is also true in vivo.

High-performance liquid chromatography with electrochemical detection applied to the analysis of 3,4-dihydroxymethamphetamine in human plasma and urine

Metabolic activation in the disposition of 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") has been implicated in some of its pharmacological and toxicological effects, with the major metabolite 3,4-dihydroxymethamphetamine (HHMA) as a putative toxicant through the formation of thioether adducts. We describe the first validated method for HHMA determination based on acid hydrolysis of plasma and urine samples, further extraction by a solid-phase strong cation-exchange resin (SCX, benzenesulfonic acid), and analysis of extracts by high-performance liquid chromatography with electrochemical detection. The chromatographic separation was performed in an n-butyl-silane (C4) column and the mobile phase was a mixture of 0.1 M sodium acetate containing 0.1 M 1-octanesulphonic acid and 4 mM EDTA (pH 3.1) and acetonitrile (82:18, v/v). Compounds were monitored with an electrochemical cell (working potentials 1 and 2, +0.05 and +0.35 V, respectively, gain 60 microA). A mobile phase conditioning cell with a potential set at +0.40 V was connected between the pumping system and the injector. Calibration curves were linear within the working concentration ranges of 50-1000 microg/L for urine and plasma. Limits of detection and quantification were 10.5 and 31.8 microg/L for urine and 9.2 and 28.2 microg/L for plasma. Recoveries for HHMA and DHBA (3,4-dihydroxybenzylamine, internal standard) were close to 50% for both biological matrices. Intermediate precision and inter-day accuracy were within 3.9-6.5% and 7.4-15.3% for urine and 5.0-10.8% and 9.2-13.4% for plasma.

Arginine vasopressin release in response to the administration of 3,4-methylenedioxymethamphetamine ("ecstasy"): is metabolism a contributory factor?

The aim of this investigation was to examine the effect of 3,4-methylenedioxymethamphetamine (MDMA) administration on arginine vasopressin (AVP) release. (R,S)-MDMA (40 mg) was administered to eight normally hydrated healthy male volunteers (22-32 years) and blood samples were collected up to 24 h. Plasma was assayed for AVP and cortisol by radioimmunoassays, and for MDMA and the N-demethylated metabolite, MDA, by gas chromatography-mass spectrometry. Sodium concentrations and osmolality were also determined. Plasma AVP increased in all subjects after MDMA administration and a significant negative correlation was observed between concentrations of AVP and both single and total enantiomer MDMA at 1 h (r < -0.91, P < 0.01). This had disappeared by 2 h (P > 0.7). Compared with basal values, no significant change was observed for osmolality or cortisol at 1 h after drug administration. In conclusion, plasma AVP concentrations increase after MDMA administration, but the increase is not part of a generalized stress response since cortisol did not increase concurrently. A significant negative correlation between plasma MDMA and AVP was observed soon after administration. The possibility that a pharmacological effect of MDMA is primarily mediated via one or more metabolites, rather than by the parent drug, should be considered.

Quantification of 3,4-methylenedioxymetamphetamine and its metabolites in plasma and urine by gas chromatography with nitrogen-phosphorus detection

A gas chromatographic method with nitrogen-phosphorus detection involving a solid-liquid extraction phase was developed and validated for the simultaneous quantification of 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA) in plasma. A modification of this method was validated for the analysis of MDMA, MDA, 4-hydroxy-3-methoxymethamphetamine (HMMA) and, 4-hydroxy-3-methoxyamphetamine (HMA) in urine. Under the analytical conditions described, the limits of detection in plasma and urine were less than 1.6 microg/l and 47 microg/l, respectively, for all the compounds studied. Good linearity was observed in the concentration range evaluated in plasma (5-400 microg/l) and urine (100-2000 microg/l) for all compounds tested. The recoveries obtained from plasma were 85.1% and 91.6% for MDMA and MDA, respectively. Urine recoveries were higher than 90% for MDMA and MDA, 74% for HMMA, and 64% for HMA. Methods have been successfully used in the assessment of plasma and urine concentrations of MDMA and its main metabolites in samples from clinical studies in healthy volunteers.

Lethal monointoxication by overdosage of MDEA

A 19-year-old man died after the intake of ten tablets of Ecstasy containing 3,4-methyl-enedioxy-N-ethylamphetamine (MDEA) as the main active ingredient. According to an eyewitness the symptoms of intoxication were strong sweating, sudden aggressiveness followed by hallucinations, subsequent failure of motoric coordination, severe spasms of arms and back, complete depression of the respiratory system, unconsciousness, and collapse. Resuscitation by an emergency doctor failed. Major autopsy findings were severe vascular congestion of all internal organs, liquid post-mortem blood, numerous subpleural and subepicardial petechial haemorrhages. By GC/MS analysis, MDEA was found in large amounts in serum (12 mg/l in femoral vein, 22 mg/l in heart blood serum), urine (201 mg/l), brain (18 to 28 mg/l) and in other tissue samples. Scalp-hair was highly positive for MDEA (17 ng/mg). Besides MDEA and its metabolites only trace amounts of MDMA could be found in urine and blood; no other drugs were detected. It can be concluded that the cause of death was a monointoxication by overdosage of MDEA.

Enantioselective determination of 3,4-methylene-dioxymethamphetamine and two of its metabolites in human urine by cyclodextrin-modified capillary zone electrophoresis

Using capillary zone electrophoresis with a phosphate buffer at pH 2.5 containing 30 mM (2-hydroxypropyl)-beta-cyclodextrin as chiral selector, the simultaneous separation of the enantiomers of 3,4-methylenedioxymethamphetamine (MDMA or Ecstasy) and its two metabolites 4-hydroxy-3-methoxymethamphetamine (HMMA) and 3,4-methylenedioxyamphetamine (MDA) in human urine is reported. The assay described is based upon enzymatic hydrolysis of conjugated HMMA (major urinary metabolite) and solid-phase extraction followed by injection of a few nL of the extract onto a 50 microm internal diameter (ID) fused-silica capillary of 60 cm length. Solutes are detected via on-column absorbance at 195 nm. For 375 ng/mL drug levels, intraday and interday imprecision is < 4%. With 5 mL urine samples, the detection limit is in the 20-50 ng/mL range. Via analysis of the urines of two patients, the metabolism of MDMA is demonstrated to be enantioselective, with significantly higher urinary amounts of R-(-)-MDMA being excreted compared to S-(+)-MDMA. Within 72h after drug administration one patient was determined to excrete 42.28 and 10.16% of the racemic MDMA dose (1.5 mg/kg body weight) as R-(-) and S-(+)-MDMA enantiomers, respectively. Corresponding values for the second subject were found to be 28.63 and 9.34%. The metabolism of the enantiomers of the two metabolites showed interindividual differences. The first and second detected HMMA enantiomers represented 3.79 and 5.42% (first subject) and 8.51 and 4.36% (second), respectively, of the administered MDMA dose. For the MDA enantiomers, corresponding values were 2.44, 1.76, 0.75, and 0.79%, respectively.

Hair analysis for drug abuse. XV. Disposition of 3, 4-methylenedioxymethamphetamine (MDMA) and its related compounds into rat hair and application to hair analysis for MDMA abuse

In order to clarify the mechanism of drug incorporation into hair, disposition of 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), 3-methoxy-4,5-methylenedioxyamphetamine (MMDA) and metabolites of MDMA, 4-hydroxy-3-methoxyamphetamine (HMAP) and 4-hydroxy-3-methoxymethamphetamine (HMMA), into hair was investigated with an animal model. After the intraperitoneal administration of those six drugs to pigmented hairy rats (5 mg/kg/day, 10 days, n = 3), the parent compounds and their metabolites in the rat plasma (5, 15, 30, 60, 120, 360 min after administration) and in the newly grown rat hair for 4 weeks were determined by GC/MS-SIM. When the ratio of hair concentration to area under the concentration versus time curves (AUCs) in plasma was represented as an index of incorporation rate (ICR) of drugs into hair, the order of ICRs was HMAP < MDA < HMMA < MDMA < MDEA < MMDA. In the comparison between MDA, MDMA and MDEA, their ICRs increased according to the length of carbon branches from proton to ethyl at the N position. From the point of view that the ICRs of MMDA was 2.3 times as much as that of MDA, the methoxy group on the benzene ring seemed to serve as a positive factor for the ICR. However, the ICRs of 4-hydroxy-3-methoxy compounds, HMAP and HMMA, were lower in comparison with those of MDA and MDMA, respectively. On the other hand, the ICRs of MDA, MDMA and MDEA were 5.5-6.1 times larger than those of amphetamine, methamphetamine and ethylamphetamine, suggesting that the methylenedioxy group on the benzene ring raises their ICRs very positively. Moreover, in order to apply the results from the animal experiments to human cases, the scalp hair samples of seven MDMA abusers were analyzed. MDMA and its metabolites, MDA; were simultaneously detected in all the samples by GC/MS. In the two samples, MDEA was found in addition to MDMA and MDA. It was shown that a hair sample is a good specimen for the confirmation of retrospective use of methylenedioxyamphetamines.

On the metabolism and the toxicological analysis of methylenedioxyphenylalkylamine designer drugs by gas chromatography-mass spectrometry

Designer drugs of the methylenedioxyphenylalkylamine type are increasingly abused. Studies on their metabolism in humans are necessary to develop a reliable gas chromatography--mass spectrometry (GC-MS) screening procedure. Such a method must allow their detection in urine for drug testing in clinical and forensic toxicology. Studies on racemic methylenedioxyamphetamine (MDA), methylenedioxymetamphetamine (MDMA), methylenedioxyethylamphetamine (MDE), benzodioxazolylbutanamine (BDB), and N-methylbenzodioxazolylbutanamine (MBDB) are presented. The metabolites were identified by GC-MS after enzymatic hydrolysis, isolation (pH 4.5 and 8-9), and derivatization (acetylation followed by methylation). The drugs undergo two overlapping metabolic pathways: O-dealkylation of the methylenedioxy group to dihydroxy derivatives followed by methylation of one of the hydroxy groups and successive degradation of the side chain to N-dealkyl and deaminooxo metabolites. MDA, MDMA, and MDE are subsequently metabolized to glycine conjugates of the corresponding 3,4-disubstituted benzoic acids. The hydroxy metabolites are excreted in a conjugated form. Based on these results, a GC-MS procedure was developed for simultaneous screening and identification of these designer drugs and/or their metabolites in urine after acid hydrolysis, isolation at pH 8-9, and acetylation. With use of mass chromatography with the most characteristic fragment ions m/z 58, 72, 86, 150, 162, 164, 176, and 178, the presence of the designer drugs was indicated and the peak underlying spectra could be identified by computerized comparison with reference spectra recorded during the presented studies. The procedure was suitable to detect an abuse of or an intoxication with the studied designer drugs (detection limit 5-50 ng/ml).

Disposition of methylenedioxymethamphetamine and three metabolites in the brains of different rat strains and their possible roles in acute serotonin depletion

3,4-Methylenedioxymethamphetamine (MDMA) affects both dopamine and serotonin (5-HT) systems. One of its acute actions is to cause a reversible fall in steady-state brain 5-HT concentrations. To investigate the chemical basis of this acute effect, the brain levels of the parent compound and three major metabolites, 3,4- 3,4-methylenedioxyamphetamine (MDA), 3,4-dihydroxymethamphetamine (DHMA) and 6-hydroxy-3,4-methylenedioxymethamphetamine (6-OHMDMA), were monitored, together with 5-HT levels, over a period of 6 hr in male Sprague-Dawley (SD) rats. The temporal relationships between drug concentrations of both stereoisomers and depletions were evaluated first. There was no correlation between the concentrations of the compounds measured and the extent of 5-HT depletion. Brain levels of MDMA and MDA were higher than plasma levels and exhibited a stereoselectivity in that (-)-MDMA and (+)-MDA levels were higher than those of enantiomers. The relationship between the dose of ((+)-MDMA and reduction in 5-HT levels was next investigated in SD male, SD female, and Dark Agouti (DA) female rats. These animals exhibit different capabilities of MDMA metabolism. There is a lower level of MDA, the N-demethylated metabolite of MDMA, in female SD rats than in males. Female DA rats are deficient in CYP2D isozymes, one of the enzymes responsible for demethylenation of MDMA to DHMA at pharmacological concentrations of substrate. there was a significant accuulation of MDMA in the brain and plasma of DA rats, but their 5-HT depletion was somewhat attenuated. The results indicated that MDMA ++ was apparently not the single, causative agent for the acute 5-HT depletion, which may also involve a metabolite formed by CYP2D.

The use of toxicokinetics for the safety assessment of drugs acting in the brain

Pharmacological and toxicological studies undertaken on drugs that affect the brain are frequently performed in disparate species under various experimental conditions, at doses often greatly in excess of those expected to be administered to humans, and the findings are extrapolated implicitly or explicitly with scant regard to differences in the biodisposition of the drugs. Such considerations are necessary since: 1. Species; 2. Strain; 3. Gender; 4. Route; 5. Dose; 6. Frequency and time of administration; 7. Temperature; 8. Coadministration of drugs; and 9. Surgical manipulation are but some of the factors that have been shown to influence the kinetics and metabolism of drugs. This article, using MDMA and other phenylethylamines as examples, provides evidence for the need to measure the exposure of the drugs and their active metabolites in blood and brain (toxicokinetics) in order that conclusions based only on dynamic, biochemical, or histological evidence are more pertinent. Further, the combined use of toxicokinetic-dynamic modeling can lead to a better appreciation of the mechanisms involved and a more useful approach to the calculation of safety margins.

Comparative investigation of disposition of 3,4-(methylenedioxy)methamphetamine (MDMA) in the rat and the mouse by a capillary gas chromatography-mass spectrometry assay based on perfluorotributylamine-enhanced ammonia positive ion chemical ionization

A gas chromatography-mass spectrometry assay based on perfluorotributylamine-enhanced ammonia positive ion chemical ionization has been developed for MDMA and three of its primary metabolites in biological specimens; the assay is linear from 2 to 1000 ng ml-1. Quantitatively, more of an administered dose of 10 mg kg-1 MDMA was excreted by the mouse (72%) than by the rat (35%); most in both species was excreted in urine and within 24 h. The difference in per cent excretion is entirely due to proportionally greater excretion of the parent drug by the mouse. 4-Hydroxy-3-methoxymethamphetamine (HMM) is the major urinary metabolite in both species. HMM and another primary metabolite, 4-hydroxy-3-methoxyamphetamine (HMA), were excreted mainly as glucuronide and sulphate conjugates (> 85%).

In vivo formation of aromatic hydroxylated metabolites of 3,4-(methylenedioxy)methamphetamine in the rat: identification by ion trap tandem mass spectrometric (MS/MS and MS/MS/MS) techniques

Aromatic hydroxylation has been established as a pathway for the in vivo metabolism of 3,4-(methylenedioxy)methamphetamine (MDMA) in the rat. Hydroxylation occurred at positions 2, 5 and 6 of the 3,4-methylenedioxyphenyl ring, but is favored at the 6 position. All three regioisomers of both hydroxy-MDMA and hydroxy-3,4-(methylenedioxy)amphetamine (hydroxy-MDA) were detected in the rat liver when 20 mg kg-1 of MDMA was administered. However, 6-hydroxy-MDMA and 6-hydroxy-MDA were the only hydroxylated metabolites detected in the rat brain and plasma and no hydroxylated metabolites were detected in the urine. The hydroxylated metabolites were identified by co-injection of synthetic reference compounds and comparison of the mass spectra of the trifluoroacetyl derivatives of the metabolites with the synthesized reference compounds. The regioisomers of both hydroxy-MDMA and hydroxy-MDA could not be distinguished by either single-stage or two-stage mass analysis. However, employment of a third stage of mass analysis produced distinctly different mass spectra for each of the three regioisomers.

Identification of metabolites of 3,4-methylenedioxymethamphetamine in rats

Liquid chromatography with electrochemical detection (LC/ECD) and gas chromatography/mass spectrometry (GC/MS) were used to identify metabolites of N-methyl-3,4-methylenedioxyamphetamine (MDMA) in samples of rat plasma and urine. Several potential metabolites, based on what is known about the metabolism of the desmethyl analog (i.e., MDA), were synthesized as standards to aid in the identification of the MDMA metabolites. MDA and N-methyl-1-(4-hydroxy-3-methoxy-phenyl)-2-aminopropane (3b) were identified in urine by HPLC and confirmed by GC/MS. 1-(4-Hydroxy-3-methyoxyphenyl)2-aminopropane, (3a), N-methyl-1-(3-hydroxy-4-methoxyphenyl)-2-aminopropane (2b) and 1-(3,4-dihydroxyphenyl)-2-aminopropane (4a) were tentatively identified by LC/ECD but insufficient sample size precluded confirmation by mass spectrometry. MDA was also identified in brain and plasma extracts. Because MDA is a metabolite of MDMA in humans, and because it has been speculated that the neurotoxic effects of MDA and MDMA may be due to a metabolite, the results of the present study may ultimately aid our understanding of the neurotoxic mechanism of these drugs of abuse.