Phenibut screening and quantification with liquid chromatography-tandem mass spectrometry and its application to driving cases.

An analytical strategy for identification by an LC-MS/MS multitarget screening method and a suitable LC-MS/MS based quantification were developed for the psychotropic drug phenibut. The samples analyzed were collected during traffic control and were associated with driving under the influence of drugs. A positive sample for phenibut was identified in a single case of driving under the influence. The quantification revealed a drug concentration of 1.9 µg/mL. An interaction with blood alcohol (BAC = 0.10%) was discussed as the explanation of the way of driving and deficit manifestations observed (swaying, nystagmus, quivering of the eyelid, and reddened eyes). According to the available information, the quantified phenibut concentration could be explained by an intake of four tablets (self-reported) during the day containing 250 mg of the drug. Chromatography was performed with a Luna 5 µm C18 (2) 100 A, 150 mm × 2 mm analytical column, and a buffer system consisted of 10 mM ammonium acetate and 0.1% acetic acid (v/v) included in mobile phases marked as A (H2 O/methanol = 95/5, v/v) and B (H2 O/methanol = 3/97, v/v). An effective limit of detection (LOD = 0.002 µg/mL) could be achieved for the multitarget screening method. The quantification of phenibut was performed on a second LC-MS/MS system with LOD/LOQ values of 0.22/0.40 µg/mL. Since phenibut quantification data are rare, the presented information can be used with caution for evaluation of positive cases in the future.

Interpretation of melperone intoxication: post-mortem concentration distribution and interpretation of intoxication data.

OBJECTIVES: Since melperone abuse with lethal intoxication is common, expert opinions based on therapeutical and lethal concentration ranges can be considered as important. Because there is a lack of information about fatalities caused by melperone mono-intoxications and data on tissue samples with concentration distribution, the aim of this work is the examination of lethal concentration ranges of melperone and drug quantification in different matrices. METHODS: An LC-MS/MS method was applied for analyses performed in blood and tissue samples. Quantification based on standard addition and sample preparation on liquid-liquid extraction with 1-chlorobutane. An appropriate tissue homogenization was performed ahead of extraction with an IKA Ultra-Turrax-Tube-Drive®. A Luna 5 µm C18 (2) 100 Å, 150  × 2 mm analytical column was used for chromatographic separation and the elution was performed with two mobile phases consisted of A (H2O/methanol = 95/5, v/v) and B (H2O/methanol = 3/97, v/v) both with 10 mM ammonium acetate and 0.1% acetic acid. RESULTS: A multi-drug LC-MS/MS analytical method developed was applied successfully for melperone quantification in different post-mortem matrices. No analytical problems could be identified during method development and analyses of real samples. The melperone lethal concentration calculated in femoral blood of the drug mono-intoxication investigated was 10 mg/L. Melperone concentration distribution was presented for the first time. CONCLUSIONS: The lethal reference concentration of melperone in femoral blood of 17.1 mg/L pointed out in different reference lists should be used with caution. Instead, a lower lethal melperone concentration should be considered. The post-mortem concentration distribution of the drug presented could be helpful in the interpretation of cases where no blood samples are available.

Interpretation of melperone intoxication: post-mortem concentration distribution and interpretation of intoxication data.

OBJECTIVES: Since melperone abuse with lethal intoxication is common, expert opinions based on therapeutical and lethal concentration ranges can be considered as important. Because there is a lack of information about fatalities caused by melperone mono-intoxications and data on tissue samples with concentration distribution, the aim of this work is the examination of lethal concentration ranges of melperone and drug quantification in different matrices. METHODS: An LC-MS/MS method was applied for analyses performed in blood and tissue samples. Quantification based on standard addition and sample preparation on liquid-liquid extraction with 1-chlorobutane. An appropriate tissue homogenization was performed ahead of extraction with an IKA Ultra-Turrax-Tube-Drive®. A Luna 5 µm C18 (2) 100 Å, 150  × 2 mm analytical column was used for chromatographic separation and the elution was performed with two mobile phases consisted of A (H2O/methanol = 95/5, v/v) and B (H2O/methanol = 3/97, v/v) both with 10 mM ammonium acetate and 0.1% acetic acid. RESULTS: A multi-drug LC-MS/MS analytical method developed was applied successfully for melperone quantification in different post-mortem matrices. No analytical problems could be identified during method development and analyses of real samples. The melperone lethal concentration calculated in femoral blood of the drug mono-intoxication investigated was 10 mg/L. Melperone concentration distribution was presented for the first time. CONCLUSIONS: The lethal reference concentration of melperone in femoral blood of 17.1 mg/L pointed out in different reference lists should be used with caution. Instead, a lower lethal melperone concentration should be considered. The post-mortem concentration distribution of the drug presented could be helpful in the interpretation of cases where no blood samples are available.

Determination of drugs in exhumed liver and brain tissue after over 9 years of burial by liquid chromatography-tandem mass spectrometry-Part 2: Benzodiazepines, opioids, and further drugs.

In this publication, benzodiazepines, opioids, and further drugs were analyzed in exhumed brain and liver tissue samples in 116 cases (total) after 9.5-16.5 years of burial. Solid phase extraction followed by liquid chromatography-tandem mass spectrometry was applied. Data from literature is listed summarizing the detectability of the presented analytes after a certain time of burial. In our study, 60% of the analyzed benzodiazepines, 100% of the opioids, and 82% of further drugs were detectable. Only the benzodiazepines lorazepam, nitrazepam, flunitrazepam, and its metabolite norflunitrazepam, and the drugs butylscopolamine, metronidazole, and omeprazole were not detectable at all. Percentage of positive findings (total, and separately for brain and liver tissue) and postmortem period are listed for each analyte. Correlation of detectability depending on postmortem period and condition of tissue are presented exemplarily for midazolam. No substantial correlation was observed. Despite a long time of burial, most benzodiazepines, opioids, and further drugs were detectable in the examined tissue samples. Our results may be a good support for future exhumations in which toxicological analyses are relevant.

Determination of drugs in exhumed liver and brain tissue after over 9 years of burial by liquid chromatography-tandem mass spectrometry-Part 1: Cardiovascular drugs.

This paper should serve as support for future exhumations in which an analysis of cardiovascular drugs is issued after over 9 years of burial. Amiodarone, amlodipine, atropine, bisoprolol, cafedrine, clonidine, esmolol, furosemide, hydrochlorothiazide, lisinopril, nifedipine, nitrendipine, phenprocoumon, torsemide verapamil, and xipamide were determined in liver and brain tissue of over 100 cases in which exhumation was performed after over 9 years of burial. Diagrams, showing the detectability depending on postmortem period as well as condition of tissues, are presented for furosemide.