Use of Lisdexamfetamine or Amphetamine? Interpretation of Chiral Amphetamine Analyses.

Amphetamine is frequently detected in forensic toxicological cases. Differentiating between the two isomers of amphetamine (d-amphetamine and l-amphetamine) and determining their relative proportion are fundamental to correctly interpret the results of toxicological analyses. The aim of this study was to examine the profile of amphetamine as well as storage stability of the isomers in authentic samples from patients chronically treated with lisdexamfetamine (LDX), the most prescribed medical amphetamine product in Sweden. Blood and urine samples were collected from 18 patients. The samples were analyzed with an achiral (racemate) method for quantification of amphetamine and with a chiral method to determine the proportion of each isomer of amphetamine. The median daily dose of LDX was 40 mg (range, 20-70 mg). The median amphetamine concentration was 0.06 µg/g (range, 0.02-0.15 µg/g) in blood and 6 µg/mL (range, 1-22 µg/mL) in urine. Only d-amphetamine was found in the blood and urine samples from the included patients. Furthermore, no formation of l-amphetamine occurred during the storage for 3 months at 4°C, 9 months at -20°C and three freeze-thaw cycles. The results from this study may be helpful in the interpretation of whether the source of identified amphetamine in biological samples is from LDX drug intake or not.

Distribution of zopiclone and main metabolites in hair following a single dose.

In forensic investigations, such as drug-facilitated crimes, reference values are useful for interpretation of hair results. The aim of this study was to establish levels of zopiclone and two main metabolites, N-desmethylzopiclone and zopiclone N-oxide, in hair after the administration of a single dose of zopiclone, as very limited data are published. A controlled study was performed, where 16 volunteers consumed either 5 or 10mg zopiclone. Hair was sampled prior to consumption and 14, 30, 60, and 120 days after intake. The deposition of drug in hair segments of all sampling time points was followed in small hair segments of 5-mm, using a validated ultra-high performance liquid chromatography-tandem mass spectrometry method. In all participants, hair segments corresponding to the time of intake were positive for zopiclone, but also with lower concentrations in the neighbouring segments. The highest zopiclone concentrations were detected in samples collected 30 or 60 days after intake. For all sampling time points maximum values for the 5-mg dose ranged from 5.0-370pg/mg for zopiclone and 5.4 to 300pg/mg for N-desmethylzopiclone, where the maximum values for the 10-mg dose ranged from 17 to 590pg/mg for zopiclone and 25-410pg/mg for N-desmethylzopiclone for all sampling time points. No significant difference in concentrations was found between the two dosing groups for either zopiclone or N-desmethylzopiclone. Almost half of the participants showed lower levels 14 days after intake than in the later sampling time points. The metabolite to parent drug ratio of N-desmethylzopiclone to zopiclone varied from 0.6 to 3.4 (median=1.2) for the maximum levels of all sampling time points. N-desmethylzopiclone are suggested to serve as an additional marker to confirm the intake of zopiclone. Traces of zopiclone N-oxide were detected in hair from only eight participants. This study showed, that it was possible to follow zopiclone and N-desmethylzopiclone in hair for 4 months even though the drugs was divided into several segments in the latest collected hair samples, and no obvious wash-out effect between the sampling time points by e.g. personal hygiene could be discerned because the cumulated amount at each sampling time point was similar. We conclude that the analysis of short segments e.g. segments of 5-mm can help determine the time of a single intake of zopiclone and that obtaining a sample 1-2 months after a drug exposure provide the best conditions to detect and interpret the results.

Evaluating the hip-flask defence in subjects with alcohol on board: An experimental study.

Driving under the influence of alcohol is a major problem for traffic-safety and a popular defence argument is alleged consumption after driving, commonly referred to as the hip-flask defence. Forensic toxicologists are often called as expert witnesses in drinking and driving cases where the suspect has claimed the hip-flask defence, to assess the credibility of the explanation. Several approaches to help the expert have been introduced but the scientific data used to support or challenge this is solely based on data from controlled single doses of ethanol administered during a short time and in abstinent subjects. In reality, we believe that even in drinking after driving cases, the subject many times has alcohol on board at time of the hip-flask drink. This questions the applicability of the data used as basis to investigate the hip-flask defence. To fill this knowledge gap, we aimed to investigate how blood and urine ethanol kinetics vary after an initial drinking session of beer and then a subsequent hip-flask drink of three different doses of whiskey. Fifteen subjects participated in the study and each provided 10 urine samples and 17 blood samples over 7h. The initial drink was 0.51g ethanol/kg and the second was either 0.25, 0.51, or 0.85g/kg. Our data suggested that the difference between the ethanol concentrations in two consecutive urine samples is a more sensitive parameter than the ratio between urine and blood alcohol to detect a recent intake when ethanol from previous intakes are already present in the body. Twelve subjects presented results that fully supported a recent intake using the criteria developed from a single intake of ethanol. Three subjects showed unexpected results that did not fully support a recent intake. We conclude that data from one blood sample and two urine samples provide good evidence for investigating the hip-flask defence even if alcohol was on board at the time of the hip-flask drink.

Validation of an LC-MS/MS method for the determination of zopiclone, N-desmethylzopiclone and 2-amino-5-chloropyridine in whole blood and its application to estimate the original zopiclone concentration in stored specimens.

2-Amino-5-chloropyridine (ACP) is a degradation product of zopiclone (ZOP) and its two main metabolites N-desmethylzopiclone (NDZOP) and zopiclone N-oxide (ZOPNO). ACP may be formed when specimens are stored. ZOP instability in blood makes interpretation of concentrations difficult especially in cases of prolonged sample storage. This study investigated how ACP could be used to estimate the original concentration of ZOP in authentic samples. For that purpose, an analytical liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the quantitation of ACP, ZOP, and NDZOP in blood was developed and validated. Due to poor extraction recovery, ZOPNO was not included in the analytical method. The method was then applied to investigate ACP formation, ZOP and NDZOP degradation in stored ZOP post-dosed authentic whole blood and two mathematical models were used to calculate the original concentration of ZOP. During storage, ACP was formed in amounts equimolar to the ZOP and NDZOP degradation. Results from samples in which ACP had been formed were used to test two models to estimate the original ZOP concentration. The correlation tests of the models showed strong correlations to the original ZOP concentration (r = 0.960 and r = 0.955) with p < 0.01 and explained more than 90 % of the ZOP concentration. This study showed that the equimolar degradation of ZOP and NDZOP to ACP could be used to estimate the original concentration of ZOP.

Quantitative analysis of zopiclone, N-desmethylzopiclone, zopiclone N-oxide and 2-amino-5-chloropyridine in urine using LC-MS-MS.

A simple liquid chromatography-tandem mass spectrometry method was validated to allow determination of zopiclone (ZOP), N-desmethylzopiclone (NDZOP), zopiclone N-oxide (ZOPNO) and 2-amino-5-chloropyridine (ACP) in urine at concentrations up to 3,000 ng/mL within 3.5 min. This method was used for quantitative analysis of the analytes in authentic urine samples obtained 10 h after oral administration of zopiclone (Imovane(®)) and in aliquots of the same urine samples after different storage conditions. In addition, pH of each studied urine sample was measured over time. The results showed that formation of ACP occurred at elevated pH and/or temperature by degradation of ZOP, NDZOP and ZOPNO. This method was also applied to samples obtained from two female victims of drug-facilitated assault. One sample had been exposed to long-term storage conditions at different temperatures and at pH >8.2, which resulted in high concentrations of ACP. The other sample, which was exposed to pH <6.5, showed no formation of ACP. ACP is formed both from ZOP and from its metabolites NDZOP and ZOPNO depending on the pH of the urine, time of storage and/or the temperature conditions. For correct interpretation in forensic cases, ZOP, its major metabolites and ACP should be analyzed. When ACP is identified in urine, the concentrations of ZOP, NDZOP and ZOPNO should be interpreted with great caution.

Influence of pre-analytical conditions on the interpretation of zopiclone concentrations in whole blood.

Zopiclone is a short-acting hypnotic drug used for treatment of insomnia and its stability has been described in some detail. However, data especially on short-term pre-analytical stability is missing. This study investigated zopiclone stability differences between spiked and authentic whole blood from subjects dosed with zopiclone. In this way influence from physiological factors such as drug interactions, matrix composition and plasma protein levels were minimized. Nine volunteers participated in the study. Whole blood was obtained before and after oral administration of 10mg Imovane(®). Aliquots of 1g of authentic and spiked blood were after initial measuring, stored at 20°C during 5 days, 5 or -20°C during 3 months, and zopiclone was measured by gas chromatography with nitrogen phosphorus detection. The results showed no stability differences between authentic and spiked blood but confirmed the very short stability in whole blood at ambient temperature. In summary, the stability was less than 1 day at 20°C, less than 2 weeks at 5°C but stable for 3 months at -20°C. This study demonstrates the importance of controlling pre-analytical conditions from sampling to analysis to avoid misinterpretation of toxicological results.

Stability tests of zopiclone in whole blood.

Zopiclone is a common drug in forensic cases and it is frequently analyzed in biological materials using different analytical methods. Zopiclone is unstable in certain solvents and depending on storage conditions unstable in biological fluids; however its stability in human whole blood has not yet been established in detail. Therefore, the following investigation was performed to study the stability of zopiclone in both spiked and authentic human blood. First, spiked blood samples were stored at -20 degrees C, 5 degrees C and 20 degrees C and the degradation of zopiclone was investigated. Second, authentic and spiked blood samples were stored at 5 degrees C and differences in zopiclone stability were studied. Third, processed sample stability and effect of freeze/thaw cycles were evaluated. Analyses were performed by GC-NPD and zopiclone concentrations were measured at selected time intervals. The study showed that zopiclone degrades in human blood depending on time and temperature and may not be detected after long-term storage. 2-amino-5-chloropyridine was identified as the primary degradation product from zopiclone. At refrigerator temperature zopiclone was stable less than 1 month in both spiked and authentic human blood samples. The best storage condition was at -20 degrees C even at short storage times, as freeze-thaw had no influence on the results. In butyl acetate extracts, zopiclone was stable at least 2 days when kept in the autosampler at ambient temperature. We conclude that preanalytical factors have great impact on analytical results and should be addressed when interpreting whole blood zopiclone concentrations.