Validation of a two-dimensional gas chromatography mass spectrometry method for the simultaneous quantification of cannabidiol, Delta(9)-tetrahydrocannabinol (THC), 11-hydroxy-THC, and 11-nor-9-carboxy-THC in plasma.

A sensitive analytical method for simultaneous quantification of sub-nanogram concentrations of cannabidiol (CBD), Delta(9)-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), and 11-nor-9-carboxy-THC (THCCOOH) in plasma is presented for monitoring cannabinoid pharmacotherapy and illicit cannabis use. Analytes were extracted from 1 mL plasma by solid-phase extraction, derivatized with N,O-bis(trimethylsilyl) trifluoroacetamide with 1% trimethylchlorosilane, and analyzed by two-dimensional gas chromatography mass spectrometry (2D-GCMS) with cryofocusing. The lower calibration curve was linear from 0.25-25 ng/mL for CBD and THC, 0.125-25 ng/mL for 11-OH-THC and 0.25-50 ng/mL for THCCOOH. A second higher linear range from 5-100 ng/mL, achieved through modification of injection parameters, was validated for THC, 11-OH-THC, and THCCOOH and was only implemented if concentrations exceeded the lower curve upper limit of linearity. This procedure prevented laborious re-extraction by allowing the same specimen to be re-injected for quantification on the high calibration curve. Intra- and inter-assay imprecision, determined at four quality control concentrations, were or=72.9% for all analytes. Analytes were stable when stored at 22 degrees C for 16 h, 4 degrees C for 48 h, after three freeze-thaw cycles at -20 degrees C and when stored on the autosampler for 48 h. This sensitive and specific 2D-GCMS assay provides a new means of simultaneously quantifying CBD, THC and metabolite biomarkers in clinical medicine, forensic toxicology, workplace drug testing, and driving under the influence of drugs programs.

Intra- and intersubject whole blood/plasma cannabinoid ratios determined by 2-dimensional, electron impact GC-MS with cryofocusing.

BACKGROUND: Whole-blood concentrations of Delta(9)-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), and 11-nor-9-carboxy-THC (THCCOOH) are approximately half of those in plasma due to high plasma protein binding and poor cannabinoid distribution into erythrocytes. Whole blood is frequently the only specimen available in forensic investigations; controlled cannabinoid administration studies provide scientific data for interpretation of cannabinoid tests but usually report plasma concentrations. Whole-blood/plasma cannabinoid ratios from simultaneously collected authentic specimens are rarely reported. METHODS: We collected whole blood for 7 days from 32 individuals residing on a closed research unit. Part of the whole blood was processed to obtain plasma, and the whole blood and plasma were stored at -20 degrees C until analysis by validated 2-dimensional GC-MS methods. RESULTS: We measured whole-blood/plasma cannabinoid ratios in 187 specimen pairs. Median (interquartile range) whole-blood/plasma ratios were 0.39 (0.28-0.48) for THC (n = 75), 0.56 (0.43-0.73) for 11-OH-THC (n = 17), and 0.37 (0.24-0.56) for THCCOOH (n = 187). Intrasubject variability was determined for the first time: 18.1%-56.6% CV (THC) and 10.8%-38.2% CV (THCCOOH). The mean whole-blood/plasma THC ratio was significantly lower than the THCCOOH ratio (P = 0.0001; 4 participants' mean THCCOOH ratios were >0.8). CONCLUSIONS: Intra- and intersubject whole-blood/plasma THC and THCCOOH ratios will aid interpretation of whole-blood cannabinoid data.

Delta9-tetrahydrocannabinol (THC), 11-hydroxy-THC, and 11-nor-9-carboxy-THC plasma pharmacokinetics during and after continuous high-dose oral THC.

BACKGROUND: Delta(9)-tetrahydrocannabinol (THC) is the primary psychoactive constituent of cannabis and an active cannabinoid pharmacotherapy component. No plasma pharmacokinetic data after repeated oral THC administration are available. METHODS: Six adult male daily cannabis smokers resided on a closed clinical research unit. Oral THC capsules (20 mg) were administered every 4-8 h in escalating total daily doses (40-120 mg) for 7 days. Free and glucuronidated plasma THC, 11-hydroxy-THC (11-OH-THC), and 11-nor-9-carboxy-THC (THCCOOH) were quantified by 2-dimensional GC-MS during and after dosing. RESULTS: Free plasma THC, 11-OH-THC, and THCCOOH concentrations 19.5 h after admission (before controlled oral THC dosing) were mean 4.3 (SE 1.1), 1.3 (0.5), and 34.0 (8.4) microg/L, respectively. During oral dosing, free 11-OH-THC and THCCOOH increased steadily, whereas THC did not. Mean peak plasma free THC, 11-OH-THC, and THCCOOH concentrations were 3.8 (0.5), 3.0 (0.7), and 196.9 (39.9) mug/L, respectively, 22.5 h after the last dose. Escherichia coli beta-glucuronidase hydrolysis of 264 cannabinoid specimens yielded statistically significant increases in THC, 11-OH-THC, and THCCOOH concentrations (P < 0.001), but conjugated concentrations were underestimated owing to incomplete enzymatic hydrolysis. CONCLUSIONS: Plasma THC concentrations remained >1 mug/L for at least 1 day after daily cannabis smoking and also after cessation of multiple oral THC doses. We report for the first time free plasma THC concentrations after multiple high-dose oral THC throughout the day and night, and after Escherichia coli beta-glucuronidase hydrolysis. These data will aid in the interpretation of plasma THC concentrations after multiple oral doses.

A mechanism for the inhibition of neural progenitor cell proliferation by cocaine.

BACKGROUND: Prenatal exposure of the developing brain to cocaine causes morphological and behavioral abnormalities. Recent studies indicate that cocaine-induced proliferation inhibition and/or apoptosis in neural progenitor cells may play a pivotal role in causing these abnormalities. To understand the molecular mechanism through which cocaine inhibits cell proliferation in neural progenitors, we sought to identify the molecules that are responsible for mediating the effect of cocaine on cell cycle regulation. METHODS AND FINDINGS: Microarray analysis followed by quantitative real-time reverse transcription PCR was used to screen cocaine-responsive and cell cycle-related genes in a neural progenitor cell line where cocaine exposure caused a robust anti-proliferative effect by interfering with the G1-to-S transition. Cyclin A2, among genes related to the G1-to-S cell cycle transition, was most strongly down-regulated by cocaine. Down-regulation of cyclin A was also found in cocaine-treated human primary neural and A2B5+ progenitor cells, as well as in rat fetal brains exposed to cocaine in utero. Reversing cyclin A down-regulation by gene transfer counteracted the proliferation inhibition caused by cocaine. Further, we found that cocaine-induced accumulation of reactive oxygen species, which involves N-oxidation of cocaine via cytochrome P450, promotes cyclin A down-regulation by causing an endoplasmic reticulum (ER) stress response, as indicated by increased phosphorylation of eIF2alpha and expression of ATF4. In the developing rat brain, the P450 inhibitor cimetidine counteracted cocaine-induced inhibition of neural progenitor cell proliferation as well as down-regulation of cyclin A. CONCLUSIONS: Our results demonstrate that down-regulation of cyclin A underlies cocaine-induced proliferation inhibition in neural progenitors. The down-regulation of cyclin A is initiated by N-oxidative metabolism of cocaine and consequent ER stress. Inhibition of cocaine N-oxidative metabolism by P450 inhibitors may provide a preventive strategy for counteracting the adverse effects of cocaine on fetal brain development.

Postmortem diagnosis and toxicological validation of illicit substance use.

The present study examines the diagnostic challenges of identifying ante-mortem illicit substance use in human postmortem cases. Substance use, assessed by clinical case history reviews, structured next-of-kin interviews, by general toxicology of blood, urine and/or brain, and by scalp hair testing, identified 33 cocaine, 29 cannabis, 10 phencyclidine and nine opioid cases. Case history identified 42% cocaine, 76% cannabis, 10% phencyclidine and 33% opioid cases. Next-of-kin interviews identified almost twice as many cocaine and cannabis cases as Medical Examiner (ME) case histories, and were crucial in establishing a detailed lifetime substance use history. Toxicology identified 91% cocaine, 68% cannabis, 80% phencyclidine and 100% opioid cases, with hair testing increasing detection for all drug classes. A cocaine or cannabis use history was corroborated by general toxicology with 50% and 32% sensitivity, respectively, and with 82% and 64% sensitivity by hair testing. Hair testing corroborated a positive general toxicology for cocaine and cannabis with 91% and 100% sensitivity, respectively. Case history corroborated hair toxicology with 38% sensitivity for cocaine and 79% sensitivity for cannabis, suggesting that both case history and general toxicology underestimated cocaine use. Identifying ante-mortem substance use in human postmortem cases are key considerations in case diagnosis and for characterization of disorder-specific changes in neurobiology. The sensitivity and specificity of substance use assessments increased when ME case history was supplemented with structured next-of-kin interviews to establish a detailed lifetime substance use history, while comprehensive toxicology, and hair testing in particular, increased detection of recent illicit substance use.

Simultaneous quantification of Delta9-tetrahydrocannabinol, 11-hydroxy-Delta9-tetrahydrocannabinol, and 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid in human plasma using two-dimensional gas chromatography, cryofocusing, and electron impact-mass spectrometry.

A two-dimensional (2D) gas chromatography/electron impact-mass spectrometry (GC/EI-MS) method for simultaneous quantification of Delta(9)-tetrahydrocannabinol (THC), 11-hydroxy-Delta(9)-tetrahydrocannabinol (11-OH-THC), and 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THCCOOH) in human plasma was developed and validated. The method employs 2D capillary GC and cryofocusing for enhanced resolution and sensitivity. THC, 11-OH-THC, and THCCOOH were extracted by precipitation with acetonitrile followed by solid-phase extraction. GC separation of trimethylsilyl derivatives of analytes was accomplished with two capillary columns in series coupled via a pneumatic Deans switch system. Detection and quantification were accomplished with a bench-top single quadrupole mass spectrometer operated in electron impact-selected ion monitoring mode. Limits of quantification (LOQ) were 0.125, 0.25 and 0.125 ng/mL for THC, 11-OH-THC, and THCCOOH, respectively. Accuracy ranged from 86.0 to 113.0% for all analytes. Intra- and inter-assay precision, as percent relative standard deviation, was less than 14.1% for THC, 11-OH-THC, and THCCOOH. The method was successfully applied to quantification of THC and its 11-OH-THC and THCCOOH metabolites in plasma specimens following controlled administration of THC.

Simultaneous GC-EI-MS determination of Delta9-tetrahydrocannabinol, 11-hydroxy-Delta9-tetrahydrocannabinol, and 11-nor-9-carboxy-Delta9-tetrahydrocannabinol in human urine following tandem enzyme-alkaline hydrolysis.

A sensitive and specific method for extraction and quantification of Delta(9)-tetrahydrocannabinol (THC), 11-hydroxy-Delta(9)-tetrahydrocannabinol (11-OH-THC), and 11-nor-9-carboxy-Delta(9)-tetrahydrocannabinol (THCCOOH) in human urine was developed and fully validated. To ensure complete hydrolysis of conjugates and capture of total analyte content, urine samples were hydrolyzed by two methods in series. Initial hydrolysis was with Escherichia coli beta-glucuronidase (Type IX-A) followed by a second hydrolysis utilizing 10N NaOH. Specimens were adjusted to pH 5-6.5, treated with acetonitrile to precipitate protein, and centrifuged, and the supernatants were subjected to solid-phase extraction. Extracted analytes were derivatized with BSTFA and quantified by gas chromatography-mass spectrometry with electron impact ionization. Standard curves were linear from 2.5 to 300 ng/mL. Extraction efficiencies were 57.0-59.3% for THC, 68.3-75.5% for 11-OH-THC, and 71.5-79.7% for THCCOOH. Intra- and interassay precision across the linear range of the assay ranged from 0.1 to 4.3% and 2.6 to 7.4%, respectively. Accuracy was within 15% of target concentrations. This method was applied to the analysis of urine specimens collected from individuals participating in controlled administration cannabis studies, and it may be a useful analytical procedure for determining recency of cannabis use in forensic toxicology applications.

A validated positive chemical ionization GC/MS method for the identification and quantification of amphetamine, opiates, cocaine, and metabolites in human postmortem brain.

A sensitive and specific method for the simultaneous detection and quantification of amphetamine, opiates, and cocaine and metabolites in human postmortem brain was developed and validated. Analytes of interest included amphetamine, morphine, codeine, 6-acetylmorphine, cocaine, benzoylecgonine, ecgonine methyl ester, ecgonine ethyl ester, cocaethylene, and anhydroecgonine methyl ester. The method employed ultrasonic homogenization of brain tissue in pH 4.0 sodium acetate buffer and solid phase extraction. Extracts were derivatized with N-methyl-N-(tert-butyldimethylsilyl) trifluoroacetamide and N,O-bis(trimethylsilyl) trifluoroacetamide. Separation and quantification were accomplished on a bench-top positive chemical ionization capillary gas chromatograph/mass spectrometer with selected ion monitoring. Eight deuterated analogs were used as internal standards. Limits of quantification were 50 ng/g of brain. Calibration curves were linear to 1000 ng/g for anhydroecgonine methyl ester and 6-acetylmorphine, and to 2000 ng/g for all other analytes. Accuracy across the linear range of the assay ranged from 90.2 to 112.2%, and precision, as percent relative standard deviation, was less than 16.6%. Quantification of drug concentrations in brain is a useful research tool in neurobiology and in forensic and postmortem toxicology, identifying the type, relative magnitude, and recency of abused drug exposure. This method will be employed to quantify drug concentrations in human postmortem brain in support of basic and clinical research on the physiologic, biochemical, and behavioral effects of drugs in humans.

Selection and optimization of hydrolysis conditions for the quantification of urinary metabolites of MDMA.

Recovery of 3,4-methylenedioxymethamphetamine (MDMA) urinary metabolites requires optimization of the hydrolysis of 4-hydroxy-3-methyoxymethamphetamine (HMMA), 4-hydroxy-3-methoxyamphetamine (HMA), and 3,4-methylenedioxyamphetamine (MDA) conjugates prior to chromatographic analysis. Acidic and enzymatic hydrolysis with beta-glucuronidase from Escherichia coli and Helix pomatia were evaluated. Acid hydrolysis yielded 40.0% and 39.3% higher HMA recovery compared to E. coli and H. pomatia hydrolysis, respectively (SE=9.8 and 11.4%). E. coli beta-glucuronidase hydrolysis MDA recovery was 17.1% and 26.5% greater than acid hydrolysis and H. pomatia beta-glucuronidase recovery (SE=3.3 and 6.1%), respectively. HMMA recovery by acid hydrolysis was 336.1% and 159.8% greater than E. coli and H. pomatia beta-glucuronidase (SE=72.8 and 31.6%), respectively. The effects of temperature, time, and acid amount on metabolite recovery were also evaluated. HMA and HMMA acid hydrolysis recoveries were improved at 100 degrees C and above. Effective hydrolysis could be conducted in a dry block heater, GC oven, or autoclave at temperatures from 100 to 140 degrees C. Optimal hydrolysis conditions for the measurement of MDMA metabolite conjugates were addition of 100 microL of hydrochloric acid to 1 mL urine and incubation at 120 degrees C in a GC oven for 40 min. Therefore, based on HMMA, HMA, and MDA recoveries, time efficiency, availability of instrumentation, and cost, acid hydrolysis was preferred to enzyme hydrolysis.

Simultaneous quantification of cannabinoids and metabolites in oral fluid by two-dimensional gas chromatography mass spectrometry.

Development and validation of a method for simultaneous identification and quantification of Delta9-tetrahydrocannabinol (THC), cannabidiol (CBD), cannabinol (CBN), and metabolites 11-hydroxy-THC (11-OH-THC) and 11-nor-9-carboxy-THC (THCCOOH) in oral fluid. Simultaneous analysis was problematic due to different physicochemical characteristics and concentration ranges. Neutral analytes, such as THC and CBD, are present in ng/mL, rather than pg/mL concentrations, as observed for the acidic THCCOOH biomarker in oral fluid. THCCOOH is not present in cannabis smoke, definitively differentiating cannabis use from passive smoke exposure. THC, 11-OH-THC, THCCOOH, CBD, and CBN quantification was achieved in a single oral fluid specimen collected with the Quantisal device. One mL oral fluid/buffer solution (0.25 mL oral fluid and 0.75 mL buffer) was applied to conditioned CEREX Polycrom THC solid-phase extraction (SPE) columns. After washing, THC, 11-OH-THC, CBD, and CBN were eluted with hexane/acetone/ethyl acetate (60:30:20, v/v/v), derivatized with N,O-bis-(trimethylsilyl)trifluoroacetamide and quantified by two-dimensional gas chromatography electron ionization mass spectrometry (2D-GCMS) with cold trapping. Acidic THCCOOH was separately eluted with hexane/ethyl acetate/acetic acid (75:25:2.5, v/v/v), derivatized with trifluoroacetic anhydride and hexafluoroisopropanol, and quantified by the more sensitive 2D-GCMS-electron capture negative chemical ionization (NCI-MS). Linearity was 0.5-50 ng/mL for THC, 11-OH-THC, CBD and 1-50 ng/mL for CBN. The linear dynamic range for THCCOOH was 7.5-500 pg/mL. Intra- and inter-assay imprecision as percent RSD at three concentrations across the linear dynamic range were 0.3-6.6%. Analytical recovery was within 13.8% of target. This new SPE 2D-GCMS assay achieved efficient quantification of five cannabinoids in oral fluid, including pg/mL concentrations of THCCOOH by combining differential elution, 2D-GCMS with electron ionization and negative chemical ionization. This method will be applied to quantification of cannabinoids in oral fluid specimens from individuals participating in controlled cannabis and Sativex (50% THC and 50% CBD) administration studies, and during cannabis withdrawal.

Extended urinary Delta9-tetrahydrocannabinol excretion in chronic cannabis users precludes use as a biomarker of new drug exposure.

BACKGROUND: Generally, urinary 11-nor-9-carboxy-Delta9-tetrahydrocannabinol (THCCOOH) after alkaline hydrolysis is monitored to detect cannabis exposure, although last use may have been weeks prior in chronic cannabis users. Delta9-Tetrahydrocannabinol (THC) and 11-hydroxy-THC (11-OH-THC) concentrations in urine following Escherichia coli beta-glucuronidase hydrolysis were proposed as biomarkers of recent (within 8h) cannabis use. OBJECTIVE: To test the validity of THC and 11-OH-THC in urine as indicators of recent cannabis use. METHODS: Monitor urinary cannabinoid excretion in 33 chronic cannabis smokers who resided on a secure research unit under 24h continuous medical surveillance. All urine specimens were collected individually ad libidum for up to 30 days, were hydrolyzed with a tandem E. coli beta-glucuronidase/base procedure, and analyzed for THC, 11-OH-THC and THCCOOH by one- and two-dimensional-cryotrap gas chromatography mass spectrometry (2D-GCMS) with limits of quantification of 2.5 ng/mL. RESULTS: Extended excretion of THC and 11-OH-THC in chronic cannabis users' urine was observed during monitored abstinence; 14 of 33 participants had measurable THC in specimens collected at least 24h after abstinence initiation. Seven subjects had measurable THC in urine for 3, 3, 4, 7, 7, 12, and 24 days after cannabis cessation. 11-OH-THC and THCCOOH were detectable in urine specimens from one heavy, chronic cannabis user for at least 24 days. CONCLUSION: For the first time, extended urinary excretion of THC and 11-OH-THC is documented for at least 24 days, negating their effectiveness as biomarkers of recent cannabis exposure, and substantiating long terminal elimination times for urinary cannabinoids following chronic cannabis smoking.

Implications of plasma Delta9-tetrahydrocannabinol, 11-hydroxy-THC, and 11-nor-9-carboxy-THC concentrations in chronic cannabis smokers.

Delta(9)-Tetrahydrocannabinol (THC) is commonly found in toxicological specimens from driving under the influence and accident investigations. Plasma cannabinoid concentrations were determined in 18 long-term heavy cannabis smokers residing on an in-patient research unit for seven days of monitored abstinence. THC, 11-hydroxy-THC, and 11-nor-9-carboxy-THC (THCCOOH) were quantified by two-dimensional gas chromatography-mass spectrometry with cryofocusing. THC concentrations were > 1 ng/mL in nine (50.0%) participants (1.2-5.5 ng/mL) on abstinence day 7. THCCOOH was detected (2.8-45.6 ng/mL) in all participants on study day 7. THC and THCCOOH median percent concentration decreases (n = 18) were 39.5% and 72.9% from day 1 to 7, respectively. Most (88.9%) of the participants had at least one specimen with increased THC compared to the previous day. Cannabis use duration and plasma THCCOOH concentrations were positively correlated on days 1-3 (R = 0.584-0.610; p = 0.007-0.011). There were no significant correlations between THC concentrations > 0.25 ng/mL and body mass index on days 1-7 (R = -0.234-0.092; p = 0.350-0.766). Measurable THC concentrations after seven days of abstinence indicate a potential mechanism for residual neurocognitive impairment observed in chronic cannabis users. THC's presence in plasma for seven days of abstinence suggests its detection may not indicate recent use in daily cannabis users.

Do Delta9-tetrahydrocannabinol concentrations indicate recent use in chronic cannabis users?

AIMS: To quantify blood Delta(9)-tetrahydrocannabinol (THC) concentrations in chronic cannabis users over 7 days of continuous monitored abstinence. PARTICIPANTS: Twenty-five frequent, long-term cannabis users resided on a secure clinical research unit at the US National Institute on Drug Abuse under continuous medical surveillance to prevent cannabis self-administration. MEASUREMENTS: Whole blood cannabinoid concentrations were determined by two-dimensional gas chromatography-mass spectrometry. FINDINGS: Nine chronic users (36%) had no measurable THC during 7 days of cannabis abstinence; 16 had at least one positive THC > or =0.25 ng/ml, but not necessarily on the first day. On day 7, 6 full days after entering the unit, six participants still displayed detectable THC concentrations [mean +/- standard deviation (SD), 0.3 +/- 0.7 ng/ml] and all 25 had measurable carboxy-metabolite (6.2 +/- 8.8 ng/ml). The highest observed THC concentrations on admission (day 1) and day 7 were 7.0 and 3.0 ng/ml, respectively. Interestingly, five participants, all female, had THC-positive whole blood specimens over all 7 days. Body mass index did not correlate with time until the last THC-positive specimen (n = 16; r = -0.2; P = 0.445). CONCLUSIONS: Substantial whole blood THC concentrations persist multiple days after drug discontinuation in heavy chronic cannabis users. It is currently unknown whether neurocognitive impairment occurs with low blood THC concentrations, and whether return to normal performance, as documented previously following extended cannabis abstinence, is accompanied by the removal of residual THC in brain. These findings also may impact on the implementation of per se limits in driving under the influence of drugs legislation.

Urinary MDMA, MDA, HMMA, and HMA excretion following controlled MDMA administration to humans.

3,4-Methylenedioxymethamphetamine (MDMA), or ecstasy, is excreted as unchanged drug, 3,4-methylenedioxyamphetamine (MDA), and free and glucuronidated/sulfated 4-hydroxy-3-methoxymethamphetamine (HMMA), and 4-hydroxy-3-methoxyamphetamine (HMA) metabolites. The aim of this paper is to describe the pattern and timeframe of excretion of MDMA and its metabolites in urine. Placebo, 1.0 mg/kg, and 1.6 mg/kg oral MDMA doses were administered double-blind to healthy adult MDMA users on a monitored research unit. All urine was collected, aliquots were hydrolyzed, and analytes quantified by gas chromatography-mass spectrometry. Median C(max), T(max), ratios, first and last detection times, and detection rates were determined. Sixteen participants provided 916 urine specimens. After 1.6 mg/kg, median C(max) were 21,470 (MDMA), 2229 (MDA), 20,793 (HMMA), and 876 ng/mL (HMA) at median T(max) of 13.9, 23.0, 9.2 and 23.3 h. In the first 24 h, 30.2-34.3% total urinary excretion occurred. HMMA last detection exceeded MDMA's by more than 33 h after both doses. Identification of HMMA as well as MDMA increased the ability to identify positive specimens but required hydrolysis. These MDMA, MDA, HMMA, and HMA pharmacokinetic data may be useful for interpreting workplace, drug treatment, criminal justice, and military urine drug tests. Measurement of urinary HMMA provides the longest detection of MDMA exposure yet is not included in routine monitoring procedures.

Two-dimensional gas chromatography/electron-impact mass spectrometry with cryofocusing for simultaneous quantification of MDMA, MDA, HMMA, HMA, and MDEA in human plasma.

BACKGROUND: 3,4-Methylenedioxymethamphetamine (MDMA, or Ecstasy) is a popular recreational drug. Analysis of MDMA and metabolites in human plasma, particularly in pharmacokinetic studies, requires low limits of quantification. Two-dimensional GC/MS with cryofocusing is a chromatographic technique recognized for its increased selectivity and resolution. METHODS: This method simultaneously quantifies 3,4-methylenedioxyethylamphetamine (MDEA), MDMA, and its metabolites, 3,4-methylenedioxyamphetamine (MDA), 4-hydroxy-3-methoxymethamphetamine (HMMA), and 4-hydroxy-3-methoxyamphetamine (HMA) in human plasma. With hydrochloric acid, we hydrolyzed 1 mL plasma, fortified with internal standard. Analytes were subjected to solid-phase extraction, derivatized with heptafluorobutyric acid anhydride, and quantified using cryofocused 2-dimensional GC/MS operated in electron-impact selected ion-monitoring mode. RESULTS: Limits of quantification were 1.0 microg/L for MDA and 2.5 microg/L for MDEA, MDMA, HMMA, and HMA. Calibration curves were linear to 100 microg/L for MDA and HMA and to 400 microg/L for MDEA, MDMA, and HMMA, with r(2) > 0.997. At 3 concentrations spanning the linear dynamic range of the assay, mean overall extraction efficiencies from plasma were > or =85% for all compounds of interest. Recoveries were 85.6% to 107.2% of target, and intra- and interassay imprecision (CV) was <8.5% for all drugs at 3 concentrations within the range of the assay. None of the 66 exogenous compounds tested interfered with analyte quantification. CONCLUSIONS: This GC/MS assay provides low limits of quantification for simultaneous determination of MDEA, MDMA, and metabolites MDA, HMMA, and HMA in human plasma. The 2D chromatographic system should be suitable for application to other analytes and to other complex matrices.