Prolonged exposure of rats to intravenous methamphetamine: behavioral and neurochemical characterization

The translational value of preclinical models of methamphetamine abuse depends in large part on the degree to which the drug regimens used in animals produce methamphetamine exposure patterns similar to those experienced by human methamphetamine abusers. To approximate one common form of methamphetamine abuse, we studied the effects of a schedule of intravenous methamphetamine administration in rats which included 2 weeks of progressively more frequent drug injections (0.125 mg/kg/injection) followed by 40 maintenance days during which animals received 40 daily injections (at 15-min intervals), with the dose gradually increasing (0.125-0.25 mg/kg per injection) every 5-10 days. This treatment produced an emerging behavioral profile characterized by gradually more continuous periods of activation consisting of progressively more intense, focused stereotypy interrupted by episodic bursts of locomotion. We also assessed markers of dopamine neurotransmission (dopamine transporter, vesicular monoamine transporter, and dopamine D1 and D2 receptors) at 15 min and (including dopamine levels) at 6 and 30 days following cessation of methamphetamine treatment. All dopamine components measured in caudate-putamen were significantly reduced at 15 min and 6 days after the final methamphetamine injection. Dopamine D1 and D2 receptors fully recovered after 30 days of drug abstinence, whereas dopamine and the dopamine transporter exhibited significant but incomplete recovery by this time point. In contrast, only the vesicular monoamine transporter exhibited no evidence of recovery over the 30-day withdrawal period. These data are discussed in terms of damage to dopamine terminals and compensatory adjustments in mechanisms maintaining functional dopaminergic transmission.

Drug interaction between methamphetamine and antihistamines: behavioral changes and tissue concentrations of methamphetamine in rats

Methamphetamine is a psychomotor stimulant, whereas first generation antihistamines cause sedation. Several studies have demonstrated that first generation antihistamines potentiate methamphetamine-induced psychomotor activation and two possible mechanisms have been postulated. One is blockage of the central histaminergic neuron system and the other is inhibition of dopamine reuptake. However, the exact mechanism is still controversial. In this study, we examined in behavioral tests the effects of selected antihistamines on methamphetamine-induced psychomotor activation in rats, and measured plasma and brain tissue concentrations of methamphetamine. We found that some antihistamines significantly potentiate methamphetamine-induced psychomotor activation in rats and that plasma and brain tissue concentrations of methamphetamine in rats treated with methamphetamine in combination with D-chlorpheniramine were markedly higher than those in rats treated with methamphetamine alone. These results suggest that the potentiating effects of antihistamines are due to not only central effects but also the alteration of the pharmacokinetics of methamphetamine.

Quantitative drug levels in stimulant psychosis: relationship to symptom severity, catecholamines and hyperkinesia

To examine the relationship between quantitative stimulant drug levels, catecholamines, and psychotic symptoms, nineteen patients in a psychiatric emergency service with a diagnosis of amphetamine- or cocaine-induced psychosis were interviewed, and plasma and urine were collected for quantitative assays of stimulant drug and catecholamine metabolite levels. Methamphetamine or amphetamine levels were related to several psychopathology scores and the global hyperkinesia rating. HVA levels were related to global hyperkinesia but not to psychopathology ratings. Although many other factors such as sensitization may play a role, intensity of stimulant-induced psychotic symptoms and stereotypies appears to be at least in part dose-related.

Drugs and driving: the Finnish perspective

Drugs can cause behavioural impairment of the driver's ability to operate safely That impairment of driving ability can be documented, and biological fluids can be tested for drugs. Most countries have legislation that covers driving under the influence of alcohol and/or drugs. Some countries have introduced zero-tolerance laws (per se laws), which prohibit the operation of a motor vehicle while an illicit drug or its metabolite is present in the body, whether or not impairment is manifested. There is growing interest in using saliva (oral fluid) in preliminary roadside testing. Legislation in the state of Victoria, Australia, already allows the use of oral fluid for evidentiary testing in the case of cannabis and methamphetamine. Nevertheless, blood testing will probably remain the most common form of evidentiary testing. It has been estimated that the prevalence of illicit drug use among the general driving population in Europe is in the range of 1-5 per cent, while the prevalence of licit drugs, such as benzodiazepines, affecting driving performance is higher: 5-10 per cent. Epidemiological research is often carried out on offenders and drivers involved in collisions. Among drivers suspected of driving under the influence of drugs, there is a high percentage of licit and/or illicit drug use, as the statistics for Finland in the present article show. The drugs of most concern are amphetamine and amphetamine-type substances, cocaine, cannabis, opiates and benzodiazepines and other sedative-hypnotics. The handling of drugs and driving cases are presented, and a summary of areas for further study are provided.

Prevalence of substance abuse among patients with physical diseases seen in an emergency room in Japan

According to a nationwide general population survey on drug use in Japan, the lifetime prevalence of methamphetamine is low when compared to the United States. To confirm the hypothesis of a lower point prevalence of methamphetamine in an emergency room (ER) in Japan than in the United States, we collected blood specimens from an urban area of heavy methamphetamine prevalence in Tokyo, Japan, and analyzed the sera using REMEDi-HS based on an unlinked anonymity. Twenty kinds of drugs other than psychotropics were detected in 55 of 279 subjects (19.7%). Nineteen kinds of psychotropics were detected in twenty (7.2%) subjects. Psychotropics were detected in eleven patients with physical diseases and no acute intoxication. Methamphetamines were detected in three subjects (1.09%, 95% confidence interval 1.073-1.088) and in one of 46 subjects with injury (2.2%). It is necessary to look at the methodological differences between this study and previous studies; however, this finding supports the lower point prevalence of methamphetamine in an ER in Japan than in an ER in the United States.

(+)-Methamphetamine-induced spontaneous behavior in rats depends on route of (+)METH administration

These studies examined the role of (+)-methamphetamine ((+)METH) administration route on spontaneous behavioral activity vs. time relationships, and pharmacokinetic mechanisms for differences in effects. Male Sprague-Dawley rats (n=6 per administration route) received saline and three doses (0.3, 1.0 and 3.0 mg/kg) of (+)METH in a mixed-sequence design by intravenous (iv), subcutaneous (sc) or intraperitoneal (ip) administration. Locomotion and stereotypy were quantified by video-tracking analysis. The effects of (+)METH on spontaneous behavior were dose- and route-dependent. In particular, total locomotor activity was greatest following 3.0 mg/kg intraperitoneally (P<0.05) and stereotypy ratings were greatest following 3.0 mg/kg subcutaneously (P<0.05). In addition, the duration of locomotor effects was greatest after 3.0 mg/kg subcutaneously (P<0.05). Serum pharmacokinetic parameters were determined in separate rats given 3.0 mg/kg by subcutaneous and intraperitoneal administration (n=4 per administration route). The (+)METH elimination half-life was not different between the routes, but the (+)METH AUC was greater (P<0.05), and the (+)METH and (+)-amphetamine (AMP) maximum concentrations occurred later following subcutaneous than after intraperitoneal dosing (P<0.05), increasing and prolonging drug exposure. In conclusion, the overall pattern of (+)METH effects on locomotor activity depend on dose and the route of administration, which affects serum concentration and the time course of behavioral effects.

The Altered Disposition of Methamphetamine in the Model of Methamphetamine-Induced Neurotoxicity

Methamphetamine (METH) is a drug of abuse, causing neurotoxic effects in mammals. Many hypotheses have been proposed to explain the underlying mechanisms of METH-induced toxicity, based on neurochemical/neuroanatomical changes. However, the pharmacokinetic properties of METH in the METH-induced neurotoxic model have not yet been evaluated. Thus, we investigated plasma and tissue levels of METH in the METH-induced neurotoxic model. As a result, when METH is administered multiply (5 mg/kg 4 times at 2-h intervals) in male Wistar rats, plasma METH levels at the third and forth injections were significantly higher than those at the first. The tissue distributions of METH in the brain as well as in the kidney were significantly decreased in the third injections, suggesting the importance of decreased transport of METH into tissues. Alternatively, one week after the establishment of METH-induced neurotoxicity, plasma levels of METH were back to normal, although METH levels in brain microdialysates were significantly higher than those in normal animals. These results suggest that the altered pharmacokinetic properties of METH, due to the abnormal membrane transport/disposition of METH into both central and peripheral tissues, might partially affect the emergence of METH-induced neurotoxicity.

Determination of methamphetamine and amphetamine in abusers' plasma and hair samples with HPLC-FL

This paper describes highly sensitive HPLC methods for the determination of amphetamine (AP) and methamphetamine (MP) in abusers' plasma and hair samples. AP and MP were derivatized with the fluorescent reagent, DIB-Cl, to yield a highly fluorescent DIB-derivatives of AP and MP, which were then analyzed by HPLC with fluorescence detection at excitation and emission wavelengths of 325 and 430 nm, respectively. The separation was achieved on an ODS column with isocratic mobile phases composed of acetoniltrile and citrate buffer (55:45, v/v) for plasma samples and of acetonitrile-methanol-citrate buffer (45:20:37.5, v/v/v) for hair samples. The limits of detection were less than 0.87 ng/mL and 0.12 ng/mg in plasma and hair samples, respectively, for both AP and MP. The methods were then applied to the determination of MP and its metabolite AP in plasma obtained from two cases of illegally ingested MP and in one of the cases' hair received later. Case I was treated with dialysis; samples before and after dialysis were analyzed by the described method. After dialysis for 5 h, the total plasma levels of AP and MP decreased from 720 to 190 ng/mL. For case II, MP and AP levels were monitored for 3 days after digestion. Total plasma levels decreased from 57 ng/mL in the day of digestion to 11 ng/mL after 3 days. In hair samples, AP and MP could also be detected in very low concentrations.

Development of a liquid chromatography–tandem mass spectrometric method for the determination of methamphetamine and amphetamine using small volumes of rat serum

The aim of this paper was to develop LC/MS/MS methodology for the determination of methamphetamine (METH) and amphetamine (AMP) using low microliter volumes (20-150 microl) of rat serum and demonstrate the use of this method for the study of serum pharmacokinetics in the rat. The analytes were extracted from rat serum using solid-phase extraction followed by an isocratic separation on a narrow-bore Hypersil C(18) column. Lower limits of quantitation for METH and AMP were 0.3 ng/ml using positive ion electrospray tandem mass spectrometry. The accuracy of the method was within 20% of the actual values over a wide range of serum concentrations. The within-day and between-day precision was better than 20% (R.S.D.). Ion-suppression matrix effects on electrospray ionization were evaluated for extracted rat serum. The LC/MS/MS method was further validated by comparing serum concentrations of METH and AMP to serum concentrations previously determined using an LC/[ (3)H]-METH assay with radiochemical detection. Finally, the LC/MS/MS method was used to study the pharmacokinetics of METH and AMP after a 1mg/kg intravenous bolus dose of METH to female Sprague-Dawley rats.

A new formulation of selegiline: improved bioavailability and selectivity for MAO-B inhibition

Seven randomised comparative studies were conducted in healthy volunteers to compare the pharmacokinetic and pharmacodynamic profiles of selegiline hydrochloride in a new formulation designed for buccal absorption "Zydis Selegiline" (1.25-10 mg) with conventional selegiline hydrochloride tablets "conventional selegiline tablets" (10 mg). A total of 156 healthy volunteers participated in these studies. Plasma concentrations of selegiline and its primary metabolites, N-desmethylselegiline (DMS), l-amphetamine (AMT), and l-methamphetamine (MET) were measured using Gas Chromatography Mass Spectrometry (GCMS) and gas liquid chromatography (GLC) assays. Inhibition of monoamine-oxidase type B (MAO-B) and monoamine oxidase type A (MAO-A) activity was determined by measurement of as beta-phenylethylamine (PEA) by GCMS and 5-hydroxyindoleacetic acid (5-HIAA) by High Performance Liquid Chromatography (HPLC) assays. Almost a third (2.96 mg) of a 10 mg selegiline dose in Zydis Selegiline was absorbed pre-gastrically (predominantly buccally) within 1 minute. Mean [SD] area-under-the curve (AUC(0- infinity)) values following Zydis Selegiline 10 mg (5.85 [7.31] ng.h/mL) were approximately five times higher than those following conventional selegiline tablets 10 mg (1.16 [1.05] ng.h/mL). In contrast, plasma concentrations of metabolites were significantly ( p<0.001) lower following Zydis Selegiline 10 mg than following conventional selegiline tablets 10 mg. Plasma concentrations of selegiline and its metabolites increased in a dose-dependent manner over the dose-range Zydis Selegiline 1.25-5 mg. Bioavailability was determined using AUC and peak plasma concentrations (C(max)). The C(max) of selegiline was similar following administration of Zydis Selegiline 1.25 mg (1.52 ng/mL) or conventional selegiline tablets 10 mg (1.14 mg/mL). The range of values for AUC(0- infinity) and C(max) following Zydis Selegiline 1.25 mg were entirely contained within the range following conventional selegiline tablets 10 mg, with a much higher variability of plasma selegiline concentrations occurring after conventional selegiline tablets than after Zydis Selegiline. As expected, peak plasma concentrations for DMS, AMT and MET were consistently lower after Zydis Selegiline 1.25 mg (1.19, 0.34, 0.93 ng/ml, respectively) than after conventional selegiline tablets 10 mg (18.37, 3.60, 12.92 ng/ml, respectively). A significant (r=0.0001) correlation between daily PEA excretion (a measure of brain MAO-B inhibition) and the log-transformed AUC((0-t)) for selegiline was demonstrated. Mean daily PEA excretion was similar following Zydis Selegiline 1.25 mg and conventional selegiline tablets 10 mg (13.0 microg versus 17.6 microg). In contrast, there was no correlation between PEA excretion and selegiline metabolites, indicating that selegiline metabolites do not significantly inhibit MAO-B. Urinary excretion of 5-HIAA (used as a marker for MAO-A inhibition) was unrelated to plasma concentrations of selegiline or DMS following single or repeat dosing of Zydis Selegiline 1.25 mg or conventional selegiline tablets 10 mg. However, comparison of treatment groups revealed a significantly lower excretion of 5-HIAA in the conventional selegiline tablets 10 mg group than in the Zydis Selegiline 1.25 mg group after repeated administration over 13 days. In summary, by reducing the opportunity for first-pass metabolism, the absorption of selegiline from Zydis Selegiline was more efficient and less variable than from conventional selegiline tablets. Compared with conventional selegiline tablets 10 mg, Zydis Selegiline 1.25 mg yielded similar plasma concentrations of selegiline and degree of MAO-B inhibition, but markedly reduced concentrations of the principal metabolites. Thus, the lower but equally MAO-B inhibitory dose of selegiline in Zydis Selegiline 1.25 mg, which is associated with lower concentrations of potentially harmful metabolites, could offer a safer and more predictable treatment in the management of patients with Parkinson's disease.

Reduced cardiovascular effects of methamphetamine following treatment with selegiline

Selegiline is a specific MAO-B inhibitor. As MAO-B has been shown to be significantly involved in the metabolism of dopamine in certain regions of the primate brain, selegiline has been proposed for use in the treatment of drug addiction. Selegiline is also metabolized in vivo to l-methamphetamine. Therefore, when given in combination with psychostimulants such as d-methamphetamine, there is the potential for adverse effects. To study this possibility, squirrel monkeys were treated with chronic selegiline and tested with two doses of d-methamphetamine (0.1 and 1.0 mg/kg, i.v.). Following at least 7 days of treatment with once daily 0.3 mg/kg i.m. selegiline, the effects of methamphetamine on blood pressure and heart rate were no different than the effects of methamphetamine observed prior to selegiline treatment. However, following at least 10 days of treatment with 1.0 mg/kg i.m. selegiline, the effects of methamphetamine on blood pressure and heart rate were significantly reduced. Both methamphetamine and amphetamine were detected in plasma following chronic selegiline treatment. When monkeys were given an acute selegiline injection prior to methamphetamine, reduced cardiovascular effects were also seen. These results indicate that selegiline can be used safely even in combination with methamphetamine, as the cardiovascular effects of the drug combination were no greater than either drug alone, and were actually reduced at the higher selegiline dose.

Concentrations and Ratios of Amphetamine, Methamphetamine, MDA, MDMA, and MDEA Enantiomers Determined in Plasma Samples from Clinical Toxicology and Driving Under the Influence of Drugs Cases by GC-NICI-MS*

Enantiomers of amphetamine (AM), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA) exhibit different pharmacological properties. This may be important for the interpretation of analytical results. Plasma samples were analyzed using validated negative ion chemical ionization gas chromatography-mass spectrometry procedures. The results for clinical toxicology cases, divided into screening (SCR) and intoxication (ITX) cases, and those of driving under the influence of drugs (DUID) cases were compared. The concentrations of all enantiomers, except R-(-)-MDA and R-(-)- and S-(+)-MA, in the SCR samples were lower than in ITX and DUID samples. Differences between concentrations in ITX and DUID samples were only significant for both enantiomers of AM (DUID higher). These findings suggested impairment in drugged drivers. Different enantiomer ratios (R vs. S) were found for AM between DUID and SCR samples, for MDMA between ITX and SCR samples, and for MDA between DUID and ITX and DUID and SCR samples. Higher MDMA enantiomer ratios in SCR compared to ITX samples are in accordance with a previously described increase of those ratios over time, possibly allowing differentiation of recent from nonrecent ingestion. Pharmacokinetic analysis of a MDMA poisoning yielded elimination half-lives of 6.0 h for R-(-)-MDMA and 4.1 h for S-(+)-MDMA. The enantiomer ratios rose exponentially over time.

Facilitation of ejaculation after methamphetamine administration in paradoxical sleep deprived rats

This study investigated the effects of methamphetamine (MA) on genital reflexes in paradoxical sleep deprived (PSD) rats. Different doses of MA (0, 4, 16 and 64 mg/kg) were acutely given after PSD or the equivalent time to control animals. We observed enhancement of spontaneous ejaculation in PSD rats with larger doses of MA, the highest of which induced ejaculation in 100% of the PSD rats. This was significantly higher than the 30% in the control. Although testosterone exerts motivational effects on male sexual behavior, our data shows that testosterone levels were lower after the PSD period in saline and in the 64 mg/kg MA groups, which present ejaculation at different rates (20% and 100%, respectively). Progesterone levels were significantly higher in PSD-saline in relation to control group and in the 16 and 64 mg/kg of MA groups compared to the other doses. Since PSD induces dopaminergic alterations and dopamine (DA) has a key role in male sexual behavior, plasma DA was also measured. The DA concentration was enhanced in all PSD groups compared with their control group. The mechanism that activates steroid hormones may represent an important physiological effect through which neurotransmitters can affect behavioral events. These data show that MA facilitates ejaculation in PSD rats, however, further studies need to be carried out in order to clarify the hormonal-neurochemical mechanisms involved.

Sudden unexpected death of a methamphetamine abuser with cardiopulmonary abnormalities: a case report

A 51-year-old man suddenly collapsed while being arrested. He was an abuser of methamphetamine (MP) with a history of previous convictions. The blood MP concentration at autopsy was below the lethal level. The heart revealed hypertrophy and endocardial thickening of the bilateral ventricles. On microscopic examination, the typical findings of hypertrophic cardiomyopathy were not seen, however endocardial thickening with increasing elastic fibres was seen in all the ventricles and in the atria. In the conduction system, the AV node artery with luminal narrowing was longitudinally compressed by circumferential tissue. Severe interstitial fibrosis and small scar formation of the superiorventricular septum were also seen. In addition, diffuse hypertensive pulmonary arteriopathy was seen in the lung parenchyma. We surmise that the AV node artery had been chronically compressed by the circumferential architecture, due to a chronic increase in intracardiac pressure. We believe that the pathological lesions noted in both the cardiac conduction system and the lung in our case may be a complication of MP abuse, and that an MP abuser with such lesions could easily die suddenly upon experiencing emotional stress.

Routine analysis of amphetamine and methamphetamine in biological materials by gas chromatography-mass spectrometry and on-column derivatization

A simple determination method of amphetamine (AP) and methamphetamine (MA) in biological materials was developed using on-column derivatization and gas chromatography-mass spectrometry (GC-MS). AP and MA in biological materials were adsorbed on the surface of Extrelut and then extracted and derivatized simultaneously on the Extrelut column. AP and MA were derivatized to the N-propoxycarbonyl derivatives using propylchloroformate. Pentadeuterated MA was used as an internal standard. The recoveries of AP and MA from urine were 88.2 and 92.5%, and those from blood were 89.7 and 90.3%, respectively. The calibration curves showed linearity in the range of 12.5-2000 ng/ml (ng/g) for AP and MA in urine and blood, and 0.25-20 ng/mg in hair. When urine samples containing two different concentrations (200 and 1000 ng/ml) of AP and MA, blood samples containing two different concentrations (200 and 1000 ng/g) of AP and MA, hair samples containing two different concentrations (0.5 and 5.0 ng/mg) of AP and MA, the coefficients of variation of intra-day and inter-day were 0.68-3.60% in urine, 0.42-4.58% in blood, and 1.20-13.1% in hair. Furthermore, this proposed method was applied to a medico-legal case of MA intoxication.

Three fatal cases of PMA and PMMA poisoning in Denmark

Paramethoxyamphetamine (PMA) and paramethoxymetamphetamine (PMMA) are methoxylated phenylethylamine derivatives with effects similar to methylenedioxymetamphetamine (MDMA) and sold as such. However, PMA and PMMA are more potent than MDMA, but have a slower onset of action, which encourages users to take more. Three fatal cases involving PMA and PMMA in Denmark in year 2000 are investigated including history, pathological, and toxicological findings. The methods used for extraction, identification, and quantitation of PMA and PMMA are described. In two of the cases, lethal postmortem blood concentrations of PMA and PMMA were determined at 3.4 and 3.3 mg/kg (case 1) and 0.78 and 0.68 mg/kg (case 3), respectively. In addition, other drugs such as MDMA, tetrahydrocannabinol, cocaine, and alcohol were involved in these cases. In the third case, death occurred four days after the ingestion of tablets containing PMA and PMMA, and therefore only low postmortem concentrations of PMA and amphetamine were detected. However, in a serum sample taken at admission to the hospital, PMA and PMMA were found, but not quantitated. It is believed that the cause of death in case 2, multiple-organ failure, was caused by overdoses of PMA and PMMA.

LC-MS/MS analysis of pholedrine in a fatal intoxication case

Pholedrine (4'-hydroxymethamphetamine) is a cardiovascular agent exerting hypertensive and adrenergic effects. High doses may cause a drop in the peripheral circulation blood flow and increase blood pressure, heart rate and body temperature up to a state of central respiratory paralysis. A 15-year-old girl who suffered from heavy agitation and hallucinations was admitted to the intensive care unit in a comatose state. The clinical findings included a maximum heart rate of 170 bpm and a body temperature of 43.8 degrees C. Resuscitation measures were in vain and abandoned after approximately 2h. A toxicological emergency analysis using GC/MS revealed a considerable amount of pholedrine in blood and urine. A method for determining pholedrine in human body fluids utilizing high-performance liquid chromatography (HPLC)/tandem mass spectrometry (LC-MS/MS) with a turbo ion-spray source was developed, using D11-methamphetamine and D5-methylenedioxymethamphetamine as internal standards. Samples were prepared by SPE extraction using SPEC-C18AR/MP3((R)) columns, which yielded the best extraction recovery (67%). Chromatographic separation was achieved at pH 5 on an RP-18 stationary phase applying gradient elution from 50 to 70% of B (methanol/acetonitrile 3/1 (v/v), 0.02% acetic acid) in A (5mM ammonium acetate/acetonitrile 95/5 (v/v), 0.02% acetic acid). Supra-pure acetic acid was added to the post-column effluent with a flow rate of 0.2 microl/min to optimize ionization. Detection was carried out in the positive ionization, multiple reaction monitoring (MRM) mode. The chromatograms showed no interference from other substances. The limit of detection (LOD, S/N=3) of pholedrine was 0.8 ng/ml and its lower limit of quantification (LLOQ, S/N=10) 3ng/ml. The calibration curve was linear (r=0.999) in the range 1-100 ng/ml. Samples with higher concentrations were diluted to suit the working range. The intra-day R.S.D. between 5 and 80 ng/ml were 3.8-8.7% and the inter-day R.S.D. between 5 and 100 ng/ml were 6.7-10.7%. The pholedrine concentrations in blood and urine collected when the girl was still alive were 16.1 microg/ml (R.S.D. 10.5%) and 1120 microg/ml (R.S.D. 8%), respectively. In post-mortem samples, they were 23.0 microg/ml (R.S.D. 5.1%) in heart blood and 27.3 microg/g (R.S.D. 6.6%) in the liver.

Quantitative analysis of desmethylselegiline, methamphetamine, and amphetamine in hair and plasma from Parkinson patients on long-term selegiline medication

Hair and plasma from patients on long-term selegiline medication were analyzed to evaluate the relationships between plasma and hair melanin concentrations and the incorporation of the selegiline metabolites methamphetamine and amphetamine in hair, and to evaluate hair analyses for determining compliance in medication. Analyses were performed on both the whole hairs, as well as pigmented and non-pigmented hairs from gray-haired patients. Melanin was quantitated by spectrophotometry, and metabolites were quantitated by gas chromatography-mass spectrometry. Concentrations in pigmented and non-pigmented hairs differed significantly for both methamphetamine (p < 0.01) and amphetamine (p < 0.02), with mean concentration ratios being 3.69 +/- 1.88 and 2.95 +/- 1.16 for methamphetamine and amphetamine, respectively. Segmental analysis indicated that some patients had not been compliant with medication. We concluded that the incorporation of methamphetamine and amphetamine into hair of single individuals shows a preference for pigmented hairs over white hairs and that segmental analysis of hair may be useful when measuring compliance with medication.

Increased plasma concentration and brain penetration of methamphetamine in behaviorally sensitized rats

Exposure to methamphetamine causes behavioral sensitization in experimental animals. However, the precise mechanism of this behavioral sensitization has not yet been fully elucidated. Accordingly, we evaluated the pharmacokinetic properties of methamphetamine in rats behaviorally sensitized to methamphetamine following its repeated administration (6 mg/kg, i.p., once a day for 5 days followed by a 21-day drug abstinence period). In the sensitized rats, methamphetamine (0.8 mg/kg)-induced locomotor activity was significantly enhanced, suggesting the successful establishment of behavioral sensitization to methamphetamine. Significant increases in the concentrations of methamphetamine in plasma and brain dialysate, as well as the delayed disappearance of methamphetamine from plasma, were observed in the sensitized rats after intravenous injection of methamphetamine (5 mg/kg). The tissue to plasma concentration ratio (Kp) of methamphetamine in lung and heart decreased in the sensitized rats. The renal excretion of methamphetamine, which is sensitive to several cations, was also decreased in the sensitized rats. Moreover, in the sensitized rats, the expression of organic cation transporter 3 (OCT3) mRNA was decreased in kidney, brain and heart as measured by reverse transcriptase-polymerase chain reaction (RT-PCR). Taken together, these results suggest that the behavioral outcome of sensitization to methamphetamine might, in part, be due to the increased levels of methamphetamine in plasma and brain extracellular areas, as well as an altered tissue distribution of methamphetamine associated with changes in the cation transport system.

Development of a rapid and sensitive method for the quantitation of amphetamines in human plasma and oral fluid by LC-MS-MS

Target analysis of amphetamines in biological samples is of great importance for clinical and forensic toxicologists alike. At present, most laboratories analyze such samples by gas chromatography-mass spectrometry. However, this procedure is labor-intensive and time-consuming, particularly as a preliminary extraction and derivatization are usually unavoidable. Here we describe the development of an alternative method. Amphetamines were isolated from human plasma and oral fluid using a simple methanol precipitation step and subsequently analyzed using reversed-phase liquid chromatography-tandem mass spectrometry. Quantitation of the drugs was performed using multiple reaction monitoring. The developed method, which requires only 50 microL of biological sample, has a total analysis time of less than 20 min (including sample preparation) and enables the simultaneous quantitation of 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxyethylamphetamine, amphetamine, methamphetamine, and ephedrine in a single chromatographic run. Limits of detection of 2 microg/L or better were obtained. The method has been validated and subsequently applied to the analysis of plasma and oral fluid samples collected from current drug users.

A fatal paramethoxymethamphetamine intoxication

During the last years in Germany a marked increase in the use of amphetamines such as 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) has been observed. The use of these recreational drugs is especially common among young people participating in rave parties. Occasionally ring-methoxylated phenethylamine derivatives like paramethoxymethamphetamine (PMMA) or paramethoxyamphetamine (PMA) are found in street drugs offered as ecstasy. These compounds exhibit a higher toxicity than the methylenedioxyamphetamine derivatives. We report on the death of a 22-year-old man after the ingestion of ecstasy pills containing PMMA and PMA. The PMMA concentration in femoral blood was 0.85 mg/l. Besides PMA (0.61 mg/l), amphetamine (0.21 mg/l), benzoylecgonine (<0.01 mg/l) and ethanol (0.46 per thousand ) were found in the blood. The case reflects the well-known fact that street drugs offered as ecstasy pills contain not necessarily MDMA but frequently differ in composition even if they have the same logo. Users of these pills therefore always take the risk of consuming pills with dangerous life-threatening ingredients. In many laboratories paramethoxyamphetamines are not detectable in routine analytical procedures. If the cause of an intoxication cannot be discovered by analytical routine methods, rarely occurring designer drugs such as PMA or PMMA should also be kept in mind.

Methamphetamine and amphetamine pharmacokinetics in oral fluid and plasma after controlled oral methamphetamine administration to human volunteers

BACKGROUND

Methamphetamine (METH) and amphetamine (AMP) concentrations in 200 plasma and 590 oral fluid specimens were used to evaluate METH pharmacokinetics and pharmacodynamics after oral administration of sustained-release METH.

METHODS

Eight participants received four oral 10-mg S-(+)-METH hydrochloride sustained-release tablets within 7 days. Three weeks later, five participants received four oral 20-mg doses. Blood samples were collected for up to 24 h and oral fluid for up to 72 h after drug administration.

RESULTS

After the first oral dose, initial plasma METH detection was within 0.25-2 h; c(max) was 14.5-33.8 micro g/L (10 mg) and 26.2-44.3 micro g/L (20 mg) within 2-12 h. In oral fluid, METH was detected as early as 0.08-2 h; c(max) was 24.7-312.2 micro g/L (10 mg) and 75.3-321.7 micro g/L (20 mg) and occurred at 2-12 h. The median oral fluid-plasma METH concentration ratio was 2.0 across 24 h and was highly variable. Neutral cotton swab collection yielded significantly higher METH and AMP concentrations than citric acid candy-stimulated expectoration. Mean (SD) areas under the curve for AMP were 21% +/- 25% and 24% +/- 11% of those observed for METH in plasma and oral fluid, respectively. After a single low or high dose, plasma METH was >2.5 micro g/L for up to 24 h in 9 of 12 individuals (mean, 7.3 +/- 5.5 micro g/L at 24 h); in oral fluid the detection window was at least 24 h (mean, 18.8 +/- 18.0 micro g/L at 24 h). The plasma and oral fluid 24-h METH detection rates were 54% and 60%, respectively. After four administrations, METH was measurable for 36-72 h (mean, 58.3 +/- 14.5 h).

CONCLUSIONS

Perceived advantages of oral fluid for verifying METH exposure compared with urine include simpler specimen collection and reduced potential for adulteration, but urine offers higher analyte concentrations and a greater window of detection.

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.