Controlled Study With MDMA

In this study, two male volunteers were given a single dose of 100 mg MDMA. MDMA was administered orally with 100 mL of tap water (two capsules each time). Subjects were swabbed in their armpit for 10 s at time zero (0, predose) and at 2, 6, 8, 12, 24, 36, and 48 h after MDMA administration. The sweat sample was collected with the wiping fleece of the test kit for amphetamines. The wiping fleece was moistened with tap water. The analysis of the sweat sample was performed in accordance with the instructions for use (3). Blood samples from the volunteers were also taken at 0 (predose), 2, 4, 6, 8, 12, and 24 h after drug administration. Blood was immediately centrifuged, and plasma was stored at -20°C until analysis. The plasma was analyzed for the presence of MDMA by GC-MS (6).

The major experimental findings with respect to the performance of Drug-wipe are summarized in Fig. 7. The concentration curve shown in the diagram is the mean plasma concentration of both volunteers. The individual curves are only slightly different, and the data are published in Pacifici et al. (6). The maximum mean value was reached after 4 h and was approx 150 ng/mL. Drug-

e 125

Time after Administration in h <-►

Diagnostic Window = Drugwipe Positive

Fig 7. Mean plasma concentrations of two volunteers after administration of 100 mg of methylenedioxymethamphetamine (MDMA). The time window where Drugwipe® was positive is indicated as "diagnostic window."

wipe test results were positive between 2 and 12 h after drug administration. Later measurements were negative. It is notable that the 2-h time point corresponds to the time of maximal physiological and psychomotoric effects of MDMA. These effects last for at least 6 h unless there is a repeated administration. The results of this pilot study support sweat testing with Drugwipe for monitoring MDMA use in the early hours following drug administration.

3.2. Roadside Trial Study and Field Operation in Germany (7,8)

In 1998, the German government extended existing traffic regulations to include testing for drugs of abuse. Following these legislative changes, traffic police in Germany undertook an evaluation of Drugwipe as a sweat test for roadside applications. Selected traffic police units were equipped with and trained in the application of Drugwipe. At the same time, police officers were also trained in the recognition of driving impairments as an initial screen for drivers under the influence of drugs. Suspected drivers were subjected to Drugwipe sweat testing. Blood samples were also taken as the standard for comparison. All blood samples were analyzed with GC-MS.

Within the time frame of the trial, 96 individuals were tested for the following drugs: cocaine, opiates, and amphetamines/methamphetamines. Drug-wipe detected 62 positive cases, whereas GC-MS test results from the blood

Time after Administration in h <-►

Diagnostic Window = Drugwipe Positive

Comparison of Drugwipe® Sweat Results With Gas Chromatography-Mass Spectrometry Blood Result in Roadside Testing

Drugwipe type

Cocaine

Opiates

Amphetamines

Total

Confirmed positives

5

8

45

58

Confirmed negatives

12

5

4

31

Unconfirmed positives

1

0

3

4

Unconfirmed negatives

1

2

0

3

samples indicated that 58 were positive. Of the 34 negatives indicated by Drug-wipe, 31 were confirmed negatives by blood analysis. Table 4 shows a breakdown of the data for the three drugs tested. Because blood was the only reference specimen, Drugwipe results were grouped into confirmed or unconfirmed positives and negatives. Overall accuracy was 93%, diagnostic sensitivity 95%, and specificity 89%. The positive predictive value is 94%. Discrepancies between Drugwipe results and the results of the blood analysis could be a result of differential pharmacological distribution of drugs in sweat and blood. During the first 30 to 90 min, there is a diagnostic window in which drug concentrations present on the skin are not yet above the cut-off values detectable by Drugwipe. In general, the concentration curve for drugs in sweat tends to shift towards a longer time window indicating a longer distribution period. The findings of this field trial, together with previous laboratory studies under controlled conditions, clearly confirm the usefulness of Drugwipe as a sweat test for roadside operations.

As a result of this field trial, the majority of the German states have since introduced Drugwipe as a sweat test for routine roadside screening for DUID. Sweat testing is favored over that of saliva because it is less invasive and more hygienic, and can even be performed without cooperation of the driver suspects. Table 5 summarizes the overall data of a 6-mo field operation in Nordrhein-Westfahlen (8) starting in the summer of 2003. Of 1763 tests, accuracy and predictive values of Drugwipe ranged between 93 and 97%. In this operation, field officers were extensively trained in impairment recognition as well as general metabolic patterns of different drugs in different human testing specimens. Through this training, the police officers developed a thorough understanding of the advantages and disadvantages of various body fluids for roadside testing and the importance of their observations during the testing process.

Table 5

Overall Accuracy and Positive Predictive Values for Drugwipe® Under Field Conditions

Table 5

Overall Accuracy and Positive Predictive Values for Drugwipe® Under Field Conditions

Cannabis

Opiates

Amph./ methamph.

Cocaine

Total number

Quantity of Drugwipes used

950

220

445

148

1763

No. of Drugwipe tests

positive in sweat

359

83

168

78

688

No. of tests not confirmed

in blood

27

2

13

8

50

Overall accuracy

97%

99%

97%

95%

97%

Positive predictive value

92%

97%

92%

90%

Securetec greatly acknowledges the cooperation of the traffic police in Germany, especially in Baden-Würtemberg and Nordrhein-Westfahlen. A special thanks to the Institute for Legal Medicine in Munich (Dr. Hans Sachs and Dr. Santjohanser) for testing and scientific discussions.

References

1. Report No. NDTA96-002A, Report on the Drugwipe evaluation study, ONDCP/ CTAC, 1966.

2. Walsh JM, Flegel R, Crouch DJ, Cangianelli L, and Baudys J. An evaluation of rapid point-of-collection oral fluid drug-testing devices. J Anal Toxicol 2003 ;27 (7):429-439.

3. Crouch DJ, Walsh JM, Flegel R, Cangianelli L, Baudys J, and Adkins R. An evaluation of selected rapid oral fluid point-of-collection drug-testing devices. J Anal Toxicol, submitted.

4. Securetec AG, Drugwipe—Instructions for Use, 2004.

5. Pichini S, Navarro M, Farre M, et al. On-site testing of MDMA ("Ecstasy") in saliva with Drugwipe® and Drugread®: a controlled study in recreational users. Clin Chem 2002;48(1): 174-176.

6. Pacifici R, Farre M, Pichini S, et al. Sweat testing of MDMA with the Drugwipe analytical device: a controlled study with two volunteers. J Anal Toxicol 2001 ;25: 144-146.

7. Landespolizeidirektion Stuttgart I, in cooperation with the Institute for Legal Medicine, Munich. Internal Evaluation Report on the Performance of Drugwipe for Cannabis, Amphetamines, Opiates and Cocaine for Roadside Testing, Stuttgart, 1998.

8. Innenministerium Nordrhein-Westfahlen. Internal Evaluation Report on the Drug-wipe: Results during the Introduction Period, 2004.

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