Purpose: Pharmacokinetic, chemical detection; to describe and report a means of measuring MDMA and its main metabolites in plasma and urine via gas chromatography with mass spectrometry (GC-MS) and a means of measuring enantiomers of MDMA, MDA and HMMA in urine with capillary electrophoresis (CE).

Design: Apparently single dose, non-placebo controlled non-blind within-subjects design. All subjects took part in treatment condition, receiving 100 mg MDMA, and all participants had blood drawn and urine collected at baseline and after drug administration.

Subjects: 6 MDMA-experienced men (reported past ecstasy use). No information is provided on participant age, but all previous publications from this team have involved participants aged 18-40 years. No information is provided on recruitment; previous papers indicate participant recruitment via "word of mouth."

Criteria for Inclusion - Male, having used ecstasy at least once in the past, extensive metabolizers for CYP2D6 activity, as assessed via dextorphan/dextromethorphan ratio, and no recent use of cocaine, amphetamines or cannabis, with verification of abstinence gathered through urinary analysis. While no information concerning participant health or past ecstasy use provided, previous publications included only those determined to be healthy after medical and psychiatric examination, and participants had to report having used ecstasy at least five times over a lifetime.

Measures: Plasma - The following were measured in plasma via GC-MS; MDMA, MDA, HMMA and HMA, with MDMA and metabolites measured in blood sampled at baseline and at 0, 15, 30, 45, 60, 75, and 90 minutes, and at 2, 3, 4, 6, 8, 10 and 24 h after drug administration.

Urine - Urinary clearance of MDMA, MDA, HMMA and HMA was measured with GC-MS, with urine collected at 0-2, 2-4, 6-8, 8-10, and 10-24 h post-drug. Urinary concentrations of MDMA and HMMA enantiomers were also detected in urine via CE. Urinary MDA was measured via CE in one individual to confirm findings reported in previous studies.

Analyses: Cmax, AUC(0-24 h), AUCtotal, k(a), K(e), t(1/2a) and t(1/2e) were calculated for plasma MDMA and HMMA. Urinary clearance was measured over time, and clearance over time was tested for linearity. Comparison of deposition for enantiomers was made for MDMA and HMMA only.

Results: Plasma - MDA represented 8% of MDMA concentrations, and HMA represented 5% of MDMA concentrations. HMMA was 5% higher than plasma MDMA concentrations (105%), indicating that it is the major MDMA metabolite in plasma. Plasma concentrations of MDMA and HMMA show a similar time course, with peak concentrations found 2 to 5 h after administration, and declining afterwards. MDA and HMA showed a later peak of 4-6 hours. Peak plasma MDMA was 223 +/- 48 ng/mL at 2.8 +/- 1 h post-drug. AUC(0,24) = 2554.8 +/- 469.7 ng/mL/H, and AUC(total) = 3020.4 +/- 589.6 ng/mL/h. MDMA half-life was calculated as 8.49 +/- 0.54 h. Peak plasma HMMA was 220.6 +/- 62.9 ng/mL at 2.5 +/- 1.2 h post-drug. AUC(0,24) = 2684.4 +/- 455.7 ng/mL/H, and AUC(total) = 3266.3 +/- 797.1 ng/mL/h. HMMA half-life was calculated as 10.13 +/- 1.73 h.

Urine - 44.7% of drug was recovered in urine over a 24 h period, with recovery as MDMA, MDA, HMMA and HMA. MDMA in urine accounted for 23.9% (123.6 +/- 24.4 umoL of drug recovered, MDA accounted for 1.8% (9.2 +/- 1.7 umoL) dose recovered. HMMA accounted for 17.1% recovered drug (88.7 +/- 31.8 umoL), and HMA accounted for 1.9% of drug recovered (9.6 +/- 5.5 umoL). Peak clearance for MDMA was recorded at 0-2 h (31.7 +/- 11.2 umoL, 6.1%), and peak HMMA was at 2-4 h (18.6 +/- 7.2 umoL, 3.6%). MDA peak concentration was at 2-4 and 4-6 h (1.5 +/- 0.8 umoL at 2-4 h and 1.5 +/- 1.0 umoL at 4-6 h). Urinary recovery of HMMA was lower than predicted from plasma AUC, and recovery of HMA was higher than predicted.

CE Analysis of Enantioselective Urinary Clearance - R-(-)-MDMA clearance was higher than S-(+)-MDMA clearance at all time periods examined, with difference in clearance growing over time. Mean of R-(-)-MDMA detected over 24 h was 80.7 +/- 19 umoL compared with a mean of 42.1 +/- 12.5 umoL for S-(+)-MDMA. Both enantiomers of MDMA had peak clearance at 0-2 h (R-(-)-MDMA = 18.5 +/- 5 umoL, S-(+)-MDMA = 13.9 +/- 3.8 umoL.) R/S ratio increased from 1.36 at 0-2 h to 4.99 at 10-24 h. However, there were no differences in deposition of R-(-)-HMMA and S-(+)-HMMA. At 24 h, 49.8 11.5 umoL of R-HMMA was detected and 41.4 +/- 21.9 umoL was detected, with an R/S ratio of 1.2. Peak clearance of both enantiomers of HMMA occurred at 2-4 h post-drug (R-(-)-MDMA = 8.3 +/- 2.3 umoL, and S-(+)-MDMA = 10.4 +/- 2.6 umoL.) The R/S ratio for HMMA neither increased nor decreased over time, though at 10-24 h after drug, R/S ratio had increased to 1.7. MDA enantiomers, assessed in 1 individual, were comparable to data gathered in other studies, with one enantiomer showing earlier clearance than the other. (These were labeled MDA-1 and MDA-2 and assumed to be equivalent to R-(-)-MDA and S-(+)-MDA.

Overall Effects: MDMA and its major metabolites were successfully measured in plasma and urine after administering 100 mg MDMA. A method of measuring concentration of the enantiomers of HMMA in urine was described and successfully performed. Peak plasma concentrations of MDMA and HMMA appeared during the same time period, but HMMA was found to have a longer half-life than MDMA (HMMA half-life = approximately 10 h versus MDMA half-life = 8 h). HMMA was found to be a major metabolite in plasma, and conjugated HMMA was found to be a major metabolite in urine. Urinary drug clearance was in the form of unmetabolized MDMA or as HMMA. Ratios for MDMA and MDA enantiomers in urine indicated enantioselective deposition, but this did not appear to be the case for HMMA enantiomers detected in urine. The R/S ratio for urinary HMMA did not change much over the time course, and was rarely greater than 1. The R/S ratio of HMMA is not opposite that of MDMA in urine because the actions of CYP 2D6 are counteracted by the actions of other non-enantioselective enzymes, such as CYP 1A2, CYP2B6 and CYP3A4.

Adverse Effects: None reported in this paper.

Comments: To date, this is the first paper reporting the deposition of two enantiomers of the MDMA metabolite HMMA in urine. A number of previous reports have described methods for detecting MDMA and its metabolites in human plasma, urine (De la Torre et al. 2000; Ortuno et al. 1999), and even saliva (Navarro et al. 2001; Picchini et al. 2002), and findings concerning the deposition of MDMA and MDA enantiomers have been previously presented (Fallon et al. 1999; Helmin et al. 1992; 1996). A recent review by Kraemer (2002) arrived at similar conclusions after considering previous findings from this research team and other publications, such as that of Helmlin and colleagues (Helmlin et al. 1992; Helmlin et al. 1996; Lanz et al. 1997). Evidence for non enantioselective metabolism of the MDMA metabolite HMMA suggest that CYP2D6 may be saturated or inactivated relatively early in the metabolism of MDMA, and that other enzymes may play more significant roles in the process. Since the study was performed in a small sample of male participants, care should be taken in generalizing findings to the general population.