Identification of metabolites of 3,4-methylenedioxymethamphetamine in rats

Identification of someN-hydroxylated metabolites of (±)-3,4-methylenedioxymethamphetamine in horse urine by gas chromatography-mass spectrometry

1. The in vivo biotransformation of (+/-)-3,4-methylenedioxymethamphetamine [(+/-)-MDMA] in the thoroughbred horse was determined after oral administration. 2. Unconjugated compounds and aglycones were isolated from enzyme-hydrolysed urine by solid-phase extraction using mixed-mode cartridges. The basic isolates were derivatized (trimethylsilylether, TMS) and analysed by positive-ion electron ionization/gas chromatography-mass spectrometry (EI+/GC-MS). MDMA and 10 Phase I metabolites containing the arylisopropylamine substructure were detected. 3. N-Hydroxy amphetamine and N-hydroxymethamphetamine were synthesized. The EI + mass spectra of their O-TMS derivatives showed characteristic alpha-cleavage ions at m/z 132 and 146, respectively, as base peaks. Based upon these data, five putative N-hydroxylated metabolites of MDMA were detected. 4. In the horse, (+/-)-MDMA is metabolized by oxidative N-demethylation to form the primary amine methylenedioxyamphetamine (MDA). Both MDMA and MDA are further metabolized by oxidative demethylenation (cleavage and O-demethylation of the benzodioxole moiety) to form the corresponding catechols, 3-O-methylation to form the guaiacols and N-oxidation of the secondary and primary amine metabolites to form the hydroxylamines. 5. Both phenolic and N-hydroxy metabolites of (+/-)-MDMA undergo Phase II conjugation before excretion in urine.

A PET study of effects of chronic 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”) on serotonin markers in Göttingen minipig brain

The psychostimulant 3,4-methylendioxymethamphetamine (MDMA, "ecstasy") evokes degeneration of telencephalic serotonin innervations in rodents, nonhuman primates, and human recreational drug users. However, there has been no alternative to nonhuman primates for studies of the cognitive and neurochemical consequences of serotonin depletion in a large-bodied animal. Therefore, we used positron emission tomography (PET) with [(11)C]DASB to map the distribution of plasma membrane serotonin transporters in brain of Göttingen minipigs, first in a baseline condition, and again at 2 weeks after treatment with MDMA (i.m.), administered at a range of doses. In parallel PET studies, [(11)C]WAY-100635 was used to map the distribution of serotonin 5HT(1A) receptors. The acute MDMA treatment in awake pigs evoked 1 degrees C of hyperthermia. MDMA at total doses greater than 20 mg/kg administered over 2-4 days reduced the binding potential (pB) of [(11)C]DASB for serotonin transporters in porcine brain. A mean total dose of 42 mg/kg MDMA in four animals evoked a mean 32% decrease in [(11)C]DASB pB in mesencephalon and diencephalon, and a mean 53% decrease in telencephalic structures. However, this depletion of serotonin innervations was not associated with consistent alterations in the binding of [(11)C]WAY-100635 to serotonin 5HT(1A) receptors. Stereological cell counting of serotonin-positive neurons, which numbered 95,000 in the dorsal raphé nucleus of normal animals, was unaffected in MDMA-treated group. group.

Synthesis and capillary electrophoretic analysis of enantiomerically enriched reference standards of MDMA and its main metabolites

Enantiomerically-enriched (S)-3,4-methylenedioxymethamphetamine (MDMA) and its main metabolites (S)-4-hydroxy-3-methoxymethamphetamine (HMMA) and (S)-3,4-dihydroxymethamphetamine (HHMA) were prepared for unequivocal identification of the differential enantioselective metabolism of these compounds as well as for its application in the analysis of biological samples. Capillary electrophoresis with cyclodextrin derivatives and a chemical correlation of (S)-MDMA, (S)-HMMA and (S)-HHMA has been performed to assign the absolute stereochemistry of major isomers in analytical standards enriched with such enantiomers.

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.

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).

Microbial transformation of 3,4-methylenedioxy-N-methylamphetamine and 3,4-methylenedioxyamphetamine

The biotransformation of 3,4-methylenedioxy-N-methylarnphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA) was examined in the fungus Cunninghamella echinulata. In addition to the reported mammalian metabolites (MDA, 3,4-methylenedioxybenzyl methyl ketoxime, 3,4-methylenedioxybenzyl methyl ketone) and the parent substrate, there were six novel metabolites detected. N-Acetyl-3,4-methylenedioxyamphetamine (NAcMDA) was unequivocally identified and three unidentified metabolites related to NAcMDA were also detected. N-Acetyl-3,4-methylenedioxy-1-phenyl-1-hydroxy-2-aminopropane was tentatively identified as a metabolite of MDMA. The only metabolite of MDA identified was NAcMDA. Two metabolites related to MDA remain unidentified.Key words: Cunninghamella, amphetamine, biotransformation, 3,4-methylenedioxy-N-methylamphetamine, 3,4-methylenedioxyamphetamine.

High-pressure liquid chromatography/electrochemical detection method for monitoring MDA and MDMA in whole blood and other biological tissues

The drug Ecstasy (3,4-methylenedioxymethamphetamine (MDMA)) is one of several hallucinogenic amphetamine derivatives reported to be serotonergic neurotoxins. The following is a description of a new high-pressure liquid chromatographic (HPLC) analytical method for the analysis of MDMA, 3,4-methylenedioxyamphetamine (MDA) and N-ethyl-3,4-methylenedioxyamphetamine (MDE) from whole blood. Upon separation of MDMA, MDA and MDE by HPLC, quantitation is achieved by use of electrochemical detection. Retention times for MDA, MDMA, and MDE are 6.5, 9.2, and 10.3 min, respectively, allowing for a complete chromatographic run every 15 min. The sensitivity of the method is 1 ng/ml which allows for measurement of MDA, MDMA, or MDE in microsamples of whole blood. The volume of blood required is very small (200 microliters); therefore, there is minimal blood loss in repeated blood sampling from small animals. Assay linearity was demonstrated from 1 ng/ml to at least 1 microgram/ml. The coefficients of variation for both intra-assay and inter-assay comparisons were less than 9%. Other HPLC methods have been previously described for the analysis of amphetamine derivatives, but this new method offers greater sensitivity, rapid turn-around time and ease of use.

Drug effects on distribution of [3H]3,4-methylenedioxymethamphetamine in mice

The present study was undertaken to examine the drug interactions between 3,4-methylenedioxymethamphetamine (MDMA) and paroxetine or several compounds including the 3,4-methylenedioxybenzyl (piperonyl) group in mice. The time course of radioactivity in the mouse brain after i.v. administration of the tracer amount (approximately 70 ng/kg) of [3H]MDMA was altered significantly by coinjection of carrier MDMA (15 mg/kg) or by pretreatment with paroxetine (10 mg/kg, i.p., 5 min). Furthermore, the radioactivity in the brain 60 min after injection of [3H]MDMA was increased significantly by pretreatment with paroxetine, but not by pretreatment with 6-nitroquipazine, fluoxetine, clomipramine, GBR 12909 or desipramine, indicating that paroxetine-induced alteration of the brain radioactivity was not due to the inhibitory effect of 5-hydroxytryptamine (5-HT) uptake of paroxetine. The radioactivity in the brain 60 min after injection of [3H]MDMA was increased significantly by pretreatment with 3,4-methylenedioxyamphetamine (MDA), MDMA, 1-piperonylpiperazine and N, alpha-dimethylpiperonylamine, but not by pretreatment with piperonylacetone, piperonyl butoxide and piperonyl isobutyrate. HPLC analyses indicated that the alteration of brain radioactivity 60 min after injection of [3H]MDMA was, in part, due to inhibition in the metabolism of [3H]MDMA to radioactive metabolite(s). The present results suggest that a specific mechanism for the 3,4-methylenedioxyphenyl group which rapidly alters the disposition and metabolism of [3H]MDMA may exist in brain and peripheral organs of mice.

Further studies on N-methyl-1(3,4-methylenedioxyphenyl)-2-aminopropane as a discriminative stimulus: antagonism by 5-hydroxytryptamine3 antagonists

Using a standard two-lever operant paradigm, male Sprague-Dawley rats were trained to discriminate 1.5 mg/kg N-methyl-1(3,4-methylenedioxyphenyl)-2- aminopropane (MDMA) from saline using a variable-interval 15-s schedule of reinforcement for food reward. Tests of stimulus antagonism were conducted to further define the mechanism of action of MDMA as a discriminative stimulus. Low doses of the 5-hydroxytryptamine1A (5-HT1A) antagonist NAN-190, the 5-HT2 antagonist pirenperone, and the dopamine antagonist haloperidol were able to somewhat attenuate the MDMA stimulus; however, none of these agents decreased MDMA-appropriate responding to less than 46%. The 5-HT3 antagonists zacopride and LY 278584 (ID50 = 0.02 micrograms/kg) antagonized the MDMA discriminative stimulus. Zacopride also attenuated the stimulus effects of 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) in DOM-trained animals but not those of (+)amphetamine in (+)amphetamine-trained animals. Several possible mechanistic interpretations are provided but it is concluded that MDMA produces its stimulus effects via a complex mechanism involving both dopaminergic and serotonergic components.

MDMA and memory: the acute and chronic effects of MDMA in pigeons performing under a delayed-matching-to-sample procedure

The purpose of the present study was to examine the acute and chronic effects of (+/-)3,4-methylenedioxy-methamphetamine (MDMA) in pigeons responding under a delayed-matching-to-sample procedure with 0-, 3-, and 6-s delays. In the absence of drug, accuracy (percent correct responses) was inversely related to delay length. When administered pre-chronically, MDMA (0.32-5.6 mg/kg) generally decreased accuracy and response rates at doses of 3.2 mg/kg and above. Although humans report a distinct "hangover" when exposure to MDMA ends, performance of pigeons in the present study did not deteriorate when the chronic regimen ended, indicating an absence of behavioral dependence on the drug. Tolerance developed following chronic exposure to 3.2 mg/kg. In general, greater tolerance occurred at the 0-s delay than at longer delays. Although MDMA is reported to have neurotoxic effects, it does not inevitably produce long-lasting or cumulative behavioral impairment.

Investigation of MDMA-related agents in rats trained to discriminate MDMA from saline

To determine whether metabolite-related analogs of N-methyl-1-(3,4-methylenedioxyphenyl)-2-aminopropane (MDMA) produce stimulus effects similar to those of the parent compound, and to determine the structural requirements associated with the MDMA stimulus, several MDMA analogs were examined in tests of stimulus generalization using rats trained to discriminate 1.5 mg/kg MDMA from saline. Although several of the analogs produced up to 50-60% MDMA-appropriate responding, none [with the exception of N-methyl-1-(4-methoxyphenyl)-2-aminopropane (PMMA)] resulted in stimulus generalization. The partial generalization, coupled with the possible reduced ability of certain of the agents to penetrate the blood-brain barrier relative to MDMA, suggests that these agents are not behaviorally inactive. PMMA, although not a metabolite of MDMA, is closely related in chemical structure to MDMA and its metabolites; PMMA produces > 80% MDMA-appropriate responding and is approximately three times more potent (ED50 = 0.2 mg/kg) than MDMA itself (ED50 = 0.76 mg/kg). PMMA is a newer scheduled substance with an as yet unknown mechanism of action; however, on the basis of the stimulus generalization observed PMMA may share some behavioral and mechanistic similarity with MDMA. These results also indicate that an intact methylenedioxy ring, such as that found in MDMA but absent in PMMA, is not a prerequisite for MDMA-like activity and further support the notion that ring-opened MDMA metabolites may produce effects that contribute to the actions of MDMA.

The neurochemical and stimulatory effects of putative metabolites of 3,4-methylenedioxyamphetamine and 3,4-methylenedioxymethamphetamine in rats

Rats were injected SC with a dose of 10 mg/kg (as base) of 3,4-methylenedioxyamphetamine (MDA), or 3,4-methylenedioxymethamphetamine (MDMA), 4-hydroxy-3-methoxyamphetamine, alpha-methyldopamine and alpha-methylnorepinephrine, metabolites of MDA, and alpha-methylepinephrine, a putative metabolite of MDMA, twice daily for either 5 or 7 consecutive doses. The rats were killed 24 h after the last injection and monoamines in discrete brain regions were assayed. MDA, MDMA, 4-hydroxy-3-methoxyamphetamine and alpha-methyldopamine, but not alpha-methylepinephrine, decreased the concentration of serotonin (5-HT) in the frontal cortex. MDA and MDMA, but not 4-hydroxy-3-methoxyamphetamine, alpha-methyldopamine and alpha-methylepinephrine, also decreased the concentration of 5-hydroxyindoleacetic acid (5-HIAA) in the frontal cortexes. In stimulatory studies, MDA and MDMA, but not their metabolites except alpha-methylepinephrine, which increased activity at 15 and 30 min, increased locomotor activity from 15 to 180 min following the drug administration.