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PubMed2000

Determination of enantiomeric amphetamines as metabolites of illicit amphetamines and selegiline in urine by capillary electrophoresis using modified beta-cyclodextrin.

The determination of enantiomeric amphetamine and methamphetamine in urine samples is important in order to distinguish use of the prescription drug selegiline (metabolized to R(-)-A and R(-)-MA) from the illicit use of S(+)-A and S(+)-MA. For the analysis of enantiomeric amphetamine (A) and methamphetamine (MA) in biological samples, the optimization of analytical condition was performed by capillary electrophoresis using chiral selectors including beta-cyclodextrin, carboxymethyl-beta-cyclodextrin and 2-hydroxypropyl-beta-cyclodextrin. We have examined the factors to obtain the best chiral resolutions, separation efficiency and sensitivity, and wide concentration linearity. Optimum resolutions were achieved using 100 mM phosphate buffer, pH 2.5, containing 10 mM of carboxymethyl-beta-cyclodextrin. This method was applied for the quantitative determination of enantiomeric amphetamine and methamphetamine in urine samples obtained from patients taking illicit amphetamines or from rats and patients taking selegiline. Acceptable quantitative results in terms of resolution, precision, sensitivity and linearity were obtained from the real urine samples containing wide-ranging concentrations of A and MA by using two concentrations of internal standards, alpha(+)- (1 microg/ml) and beta-phenylethylamine (50 microg/ml).

Amphetamines↗
PubMed2006

Development of a harmonised method for the profiling of amphetamines VI: Evaluation of methods for comparison of amphetamine.

Amphetamine samples were analysed by gas chromatography-mass spectrometry (GC-MS), and the peak areas of 33 target compounds were transformed by applying various pretreatment techniques. The objective was to optimise the ability of a number of distance metrics to establish links between samples of amphetamine originating from the same batch (henceforth referred to as linked distances). Furthermore, partial least squares discriminant analysis (PLS-DA) was used to evaluate the effects of various pretreatment methods on separation of amphetamine batches synthesised by the Leuckart reaction, reductive amination of benzyl methyl ketone, and the nitrostyrene route. The most efficient way to pretreat GC-MS data varied for the different distance metrics, although best results were obtained when data were normalised to the sum of peak areas, and either the fourth root or a logarithm was applied to the normalised data. When pretreating normalised data by fourth root transformation, Pearson correlation was the distance metric that was most successful at finding linked samples. Normalisation and the use of fourth root also represented the best method of pretreating data when employing PLS-DA to separate samples synthesised by different routes. To achieve a faster and more user-friendly procedure for evaluating chromatograms, experiments were performed in which the number of target compounds used to compare samples was reduced. The effect of each compound that was removed was studied by applying PLS-DA and by using Pearson correlation to calculate linked distances as well as unlinked distances (between samples from different batches of amphetamine). Considering both links between samples from the same batch and separation of samples synthesised by different routes, the best results were obtained with the data set comprising 26 compounds. Finally, it was found that the profiling method developed in this work was superior to an existing technique with respect to separating linked and unlinked distances.

Journal Article↗
PubMed1994

Quantitative measurement of amphetamine in human plasma by gas chromatography/negative ion chemical ionization mass spectrometry using (2H5)amphetamine as internal standard.

A selected ion monitoring stable isotope dilution gas chromatographic/negative ion chemical ionization mass spectrometric assay for amphetamine in human plasma is described. The preparation of (2H5)amphetamine from the intact target molecule and its use as an internal standard for quantitative gas chromatography/mass spectrometry are demonstrated. Derivatization to the highly electrophoric pentafluorobenzoate with pentafluorobenzoyl chloride in hexane resulted in high yield of prominent negative ions with methane as a moderating gas. The pentafluorobenzoate was also found to be superior to fluoroacyl derivatives with respect to sample handling due to its lower volatility. The method presented permits detection of amphetamine in the low picogram per millilitre range and should thus be highly useful for its trace level determination in forensic, toxicological and pharmaceutical applications.

Amphetamine↗
PubMed1991

Presynaptic dopaminergic neurotransmission mediates amphetamine-induced unconditioned but not amphetamine-conditioned locomotion and defecation in the rat.

A series of experiments were conducted to investigate the role of presynaptic dopamine (DA) and noradrenaline (NA) neurotransmission in stimulant-unconditioned and conditioned locomotion and defecation. (+)-Amphetamine (AMP, 1.5 mg/kg, s.c.) increased both locomotion and defecation in rats, and both of these effects were conditioned to environmental stimuli. Some groups of rats were treated with DSP4 (50 mg/kg, i.p.), a selective, long-lasting NA neurotoxin, given 7 days prior to conditioning with AMP. This treatment depleted forebrain NA to between 1% and 54% of control levels, depending on the brain region, but did not attenuate either AMP-unconditioned or conditioned locomotion. These results indicate that NA does not mediate either AMP unconditioned or conditioned locomotion. alpha-Methyl-para-tyrosine methyl ester (alpha MPT, 25-50 mg/kg, s.c.), a selective inhibitor of catecholamine synthesis given during conditioning with AMP, attenuated unconditioned AMP-induced locomotion and defecation but did not influence AMP-conditioned locomotion and defecation. Thus, alpha MPT blocked AMP-induced unconditioned locomotion, supporting the hypothesis that the locomotor and defecation stimulant effects of AMP are mediated by DA release. In spite of the attenuation of the direct effects of AMP, alpha MPT did not attenuate AMP-conditioned locomotion or defecation. It is concluded that AMP-induced release of dopamine is responsible for the unconditioned behavioral effects of amphetamine but not for the conditioning of amphetamine-induced locomotion and defecation.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1978

Stimulus properties of d-amphetamine as compared to l-amphetamine.

Rats were trained to discriminate between d-amphetamine and saline. The discriminable ED50 values for amphetamine isomers were calculated from dose--response curves and the potency ration was 4.9 Co-administration of the ED50s was shown to produce synergistic effects suggesting that the amphetamine isomers may share a common site of action.

Amphetamine↗
PubMed1983

beta-Phenylethylamine-, d-amphetamine-and l-amphetamine-induced place preference conditioning in rats.

The conditioned place preference paradigm was used to study the reinforcing properties of beta-phenylethylamine (PEA), d-amphetamine and l-amphetamine. The results confirmed that each drug produced place preferences for a distinctive environment that had previously been paired with the drug treatment. PEA proved as effective as the amphetamine isomers, although substantially less potent. This is the first report of a reinforcing effect of PEA in the rat and supplements previous evidence that PEA is self-administered intravenously in the dog.

Amphetamine↗
PubMed2006

Prevalence of use study for amphetamine (AMP), methamphetamine (MAMP), 3,4-methylenedioxy-amphetamine (MDA), 3,4-methylenedioxy-methamphetamine (MDMA), and 3,4-methylenedioxy-ethylamphetamine (MDEA) in military entrance processing stations (MEPS) specimens.

The Roche Abuscreen Onlinetrade mark Amphetamine immunoassay (IA), modified to include sodium periodate, and the Microgenics DRI Ecstasy IA were used to determine the prevalence of amphetamine (AMP), methamphetamine (MAMP), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA) in urine specimens from applicants seeking to join the United States Armed Forces. Over a 4-month period, a total of 85,658 specimens were IA screened using the Department of Defense 500 ng/mL administrative cutoff level for AMP and MDMA. All presumptively positive specimens were confirmed using a solid-phase extraction procedure coupled with simultaneous analysis of AMP, MAMP, MDA, MDMA, and MDEA by fast gas chromatography-mass spectrometry using the same cutoff levels as the IA. The Roche Online Amphetamine IA identified 216 specimens as presumptively positive; of these, 70 specimens confirmed positive for AMP and 87 specimens confirmed positive for AMP and/or MAMP, resulting in a confirmation rate of 73%. The Microgenics DRI Ecstasy IA identified eight specimens as presumptively positive; of these, five specimens confirmed positive for MDMA and/or MDA, resulting in a confirmation rate of 63%. The total use prevalence for AMP, MAMP, MDA, MDMA, and/or MDEA in military entrance processing stations specimens over the testing period was determined to be 0.19%.

Amphetamines↗
PubMed2002

Toxicokinetics of amphetamines: metabolism and toxicokinetic data of designer drugs, amphetamine, methamphetamine, and their N-alkyl derivatives.

This paper reviews the toxicokinetics of amphetamines. The designer drugs MDA (methylenedioxy-amphetamine, R,S-1-(3;,4;-methylenedioxyphenyl)2-propanamine), MDMA (R,S-methylenedioxymethamphetamine), and MDE (R,S-methylenedioxyethylamphetamine), as well as BDB (benzodioxolylbutanamine; R,S-1-(1;,3;-benzodioxol-5;-yl)-2-butanamine or R,S-1-(3;,4;-methylenedioxyphenyl)-2-butanamine) and MBDB (R,S-N-methyl-benzodioxolylbutanamine), were taken into consideration, as were the following N-alkylated amphetamine derivatives: amphetaminil, benzphetamine, clobenzorex, dimethylamphetamine, ethylamphetamine, famprofazone, fencamine, fenethylline, fenproporex, furfenorex, mefenorex, mesocarb, methamphetamine, prenylamine, and selegiline. English-language publications from 1995 to 2000 were reviewed. Papers describing identification of metabolites or cytochrome P450 isoenzyme-dependent metabolism and papers containing pharmacokinetic/toxicokinetic data were considered and summarized. The implications of toxicokinetics for toxicologic assessment or for interpretation in forensic cases are discussed.

Amphetamines↗
PubMed2000

Hyposensitivity to amphetamine following exposure to chlorphenvinphos--protection by amphetamine preexposure.

We investigated the effect of an acute exposure to chlorphenvinphos (CVP), an organophosphate anticholinesterase, on amphetamine-induced open-field locomotion in rats. CVP was administered in a single i.p. dose of 1.0 mg/kg (1/10 of the LD50). All animals were challenged with 1.0 mg/kg amphetamine (AMPH) three weeks after the CVP exposure, i.e. after a time sufficient for acetylcholinesterase recovery. Some rats were also given AMPH three weeks before the CVP exposure. In rats challenged with AMPH only once after the CVP exposure, AMPH-induced open-field locomotion was significantly reduced. Such an effect was not observed in rats given AMPH three weeks before the CVP exposure. The results suggest that a single CVP exposure may result in persistent dopaminergic hyposensitivity, and that an amphetamine pretreatment may protect the rat against this effect.

Amphetamine↗
PubMed1978

Interactions of catecholaminergic receptor blockers with lethal doses of amphetamine or substituted amphetamines in mice.

Lethality to both isolated and aggregated mice was determined for graded i.p. doses of d-amphetamine, dl-4-methoxyamphetamine (PMA), dl-2,5-dimethoxyamphetamine (DMA), dl-2,5-dimethoxy-4-bromoamphetamine (DOB), dl-2,5-dimethoxy-4-methylamphetamine (DOM) and d1-3,4-methylenedioxyamphetamine (MDA). Haloperidol (2.0 mg/kg), propranolol (10 mg/kg) and phenoxybenzamine (30 mg/kg) were tested for ability to antagonize the lethal effects of amphetamine and its derivatives. Considerable protection against amphetamine lethality was produced by haloperidol in both isolated and aggregated mice and by phenoxybenzamine in isolated mice, but propranolol was ineffective. An equivalent degree of protection was not achieved by use of any of the three agents before PMA, DMA or DOB. Protection against DOM was achieved only with phenoxybenzamine and only for isolated mice. Extensive protection against MDA was supplied by both phenoxybenzamine and propranolol for either condition of housing. Despite close structural relationships between the toxicants, the antidotal effectiveness of the receptor-blocking agents seemed quite limited and specific, and did not support any generalizations.

Amphetamines↗
PubMed1975

Supersensitivity to d-amphetamine- and apomorphine-induced stereotyped behavior induced by chronic d-amphetamine administration.

Guinea pigs exhibit an increased sensitivity to both d-amphetamine- and apomorphine-induced stereotyped behavior following chronic pretreatment with d-amphetamine. This chronic agonist or "innervation" supersensitivity is believed to be a reflection of an increased sensitivity of dopamine receptor sites within the corpus striatum to dopaminergic agonists. The appearance of dyskinetic movement disorders in humans following the chronic use of levodopa or amphetamine may be a manifestation of similarly increased dopamine receptor site sensitivity within the striatum. It is suggested that the animal model of "innervation" supersensitivity may be useful in the investigation of these human movement disorders.

Animals↗
PubMed2005

Development of a capillary zone electrophoresis method including a factorial design and simplex optimisation for analysis of amphetamine, amphetamine analogues, cocaine, and heroin.

A capillary zone electrophoresis (CZE) method was developed for the analysis of amphetamine and 13 amphetamine analogues. A full factorial design was used to screen for important design variables (i.e. carrier electrolyte concentration, pH, and separation temperature), and a modified simplex was employed in a final optimisation step. The resolution values of the target compounds were used as responses in the screening and optimisation phases. This approach made it possible to control the effects of the design variables on the separation of the target compounds. The best results were obtained using a 100mM Tris/phosphate buffer (pH 3.1) at a separation temperature of 10 degrees C, and the analysis time was 23 min under these conditions. After slight modification, the method also enabled baseline resolution of the most commonly encountered amphetamine derivatives, as well as cocaine and heroin, within 7 min. There was a linear relationship between peak area and concentration for all substances, with correlation coefficients in the range of 0.9975-0.9999. Moreover, the technique was repeatable and exhibited relative standard deviation (R.S.D.) values in the ranges of 0.01-0.11% and 0.54-1.60% for relative migration time and corrected peak area, respectively. Lastly, the method was successfully applied to analyse street samples.

Journal Article↗
PubMed1985

The acute effects of methamphetamine, amphetamine and p-chloroamphetamine on the cortical serotonergic system of the rat brain: evidence for differences in the effects of methamphetamine and amphetamine.

Cortical tryptophan hydroxylase (TPH) activity was reduced 3 h after a 10 or 15 mg/kg i.p. dose of either amphetamine (AMP), methamphetamine (METH), or p-chloroamphetamine (PCA). These injections of METH or PCA also decreased cortical serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) concentrations; none of the four doses of AMP decreased indoleamine concentrations. The time course of the effects following a 15 mg/kg dose of each amine was also different. Cortical TPH activity was reduced by all three amines for periods up to 24 h, whereas only METH and PCA significantly decreased 5-HT and 5-HIAA concentrations for long periods. These data suggest that each of the amphetamines may inhibit TPH activity, whereas only METH and PCA produced long-lasting decreases in indoleamine concentrations, reflecting either varying degrees of toxicity or differential effects of AMP on enzyme activity and neurotransmitter concentrations.

Amphetamine↗
PubMed1986

Metabolism and disposition of N-(2-cyanoethyl)amphetamine (fenproporex) and amphetamine: study in the rat brain.

N-(2-Cyanoethyl)amphetamine (fenproporex, CE-AM) is a clinically used anorexiant claimed to be devoid of the stimulant properties associated with amphetamine (AM). This claim was inconsistent with preliminary studies conducted in our laboratories which indicated that CE-AM is metabolically dealkylated to AM to a considerable extent in the rat. Concentration-time profiles of CE-AM and its metabolites AM and 4-hydroxyamphetamine (4-OH-AM) in the rat brain were constructed after administration of CE-AM. Analyses of CE-AM, AM, and 4-OH-AM were performed by gas chromatography with electron-capture detection using pentafluorobenzoyl chloride (under aqueous conditions) as the derivatizing reagent. The half-life (t1/2) and the maximum concentration (Cmax) of AM after administration of CE-AM were calculated to be 2.04 and 0.56 times the respective t1/2 and Cmax obtained after an equimolar dose of AM. Significant differences in the profiles of 4-OH-AM were also observed. The Cmax of 4-OH-AM in rat brain after administration of CE-AM was nearly 4 times higher and the tmax (time at which concentration is maximum) 4 times lower than the respective Cmax and tmax values of 4-OH-AM observed after an equimolar dose of AM.

Amphetamine↗
PubMed2006

Screening for amphetamine and amphetamine-type drugs in doping analysis by liquid chromatography/mass spectrometry.

A selective and sensitive method for the qualitative screening of urine samples for 27 amphetamine and amphetamine-type drugs in the field of doping analysis is described. The method consists of a liquid-liquid extraction with diethyl ether at pH 14 and analysis of the extracts with a LCQ-Deca mass spectrometer equipped with an atmospheric pressure chemical ionisation interface, operated in positive ionisation mode. The total run time was 15 min. All compounds were analysed in MS2 or MS3. The detection limit for all compounds was lower than 25 ng/mL except for chlorphentermine (detection limit: 250 ng/mL).

Amphetamine↗
PubMed1994

Animals predisposed to develop amphetamine self-administration show higher susceptibility to develop contextual conditioning of both amphetamine-induced hyperlocomotion and sensitization.

It has been shown that rats, like humans, display individual differences in the propensity to develop psychostimulant self-administration. Animals showing the highest locomotor reactivity to novelty (HRs: High Responders) are more prone to develop amphetamine self-administration than rats having a low locomotor response to novelty (LRs: Low Responders). The present study was designed to ascertain whether individual differences are also present in the conditioning of drug effects, a process involved in the maintenance of addiction. After pairing the drug effect with a particular set of environmental cues, only HRs showed conditioned hyperlocomotion and environment-specific sensitization to the effect of amphetamine. Unconditioned sensitization was, however, observed in LRs but not in HRs. The environment-specific sensitization disappeared on extinction of the conditioned hyperlocomotion in HRs, indicating that conditioning facilitates the expression of sensitization. In contrast, an inhibitory influence of conditioning on sensitization emerged from the analysis of the same results over all the experimental groups, without taking individual differences into account. In conclusion, our results show that: (i) locomotor reactivity to novelty predicts both vulnerability to develop self-administration and contextual conditioning of drug effects, which suggests that the two phenomena are two related features and that conditioning plays an important role not only in the maintenance of drug intake but also in its development; (ii) conditioned and unconditioned sensitization can be developed separately in different individuals which suggests that they are independent phenomena; (iii) analysis of individual differences is relevant to pharmacological studies, especially with respect to drugs of abuse.

Amphetamine↗
PubMed1997

Determination of amphetamine and methylenedioxy-amphetamine-derivatives in hair.

Two GC/MS-procedures for the detection of amphetamine and its methylenedioxy-derivatives (MDA, MDMA and MDE) in hair are presented. In these methods a methanol sonication extraction technique was applied. The extracted drugs were derivatized either with propionic acid anhydride (PSA) or trifluoroacetic acid anhydride (TFA). PSA-derivatives are more stable than TFA-derivatives, but the latter provide more specific mass-spectrometric information, and, therefore, seem to be preferably for amphetamine determination. The detection limit for all compounds was in a range of about 0.01 ng/mg, if at least 50-100 mg of hair were analyzed, independent of the derivatization used.

3,4-Methylenedioxyamphetamine↗
PubMed1997

Derivatization of amphetamine and methamphetamine with 1,2-naphthoquinone 4-sulfonic acid into solid-phase extraction cartridges. Determination of amphetamine in pharmaceutical and urine samples.

The derivatization of amphetamine and methamphetamine with 1,2-naphthoquinone-4-sulfonate (NQS) into solid-phase extraction cartridges (C18) is described. Optimum conditions were the use of carbonate-hydrogencarbonate buffer of pH 10, a 10 min reaction time at 25 degrees C and an NQS concentration of 9.6 x 10(-3) M. The accuracy and the precision of the method were tested. The results obtained with the proposed liquid-solid procedure were compared with those obtained with a traditional liquid-liquid extraction with hexane-ethyl acetate. The procedure was used to measure amphetamine in pharmaceutical and urine samples.

Amphetamine↗