High-Throughput Quantitative LC-MS/MS Analysis of Benzodiazepines in Human Urine

We hereby present a fast, high-throughput, and clinical LC-MS/MS assay for the simultaneous analysis of benzodiazepines in human urine. The assay is used as both a confirmations and semi-quantitative assay for the abovementioned drugs of abuse following immunoassay urine drug screens. Urine levels are reported in the range of 25 ng/mL-500 ng/mL for each of the 22 analytes, based on a six-level calibration and using a subset (10) of stable isotopically labeled analogues as internal standards. The urine sample is clarified, diluted ten times in internal standard reagent, and thereafter injected into the LC-MS/MS instrument. Reversed-phase liquid chromatography is used to separate the mixture, and the TSQ Endura triple-quadrupole (QqQ) MS instrument performs detection via positive-mode electrospray ionization multiple reaction monitoring.

Overview of the bioanalytical methods used for the determination of benzodiazepines in biological samples and their suitability for emergency toxicological analysis

Benzodiazepines are one of the most widely used classes of drugs around the world. They are medically used in different therapeutic areas including insomnia, anxiety, epilepsy, and anesthesia. Unfortunately, these drugs are very widespread in the illicit market for recreational purposes and cause drug dependence, traffic accidents, and criminality. Furthermore, benzodiazepine misuse leads to acute poisoning cases that often end up in hospital emergency rooms. Therefore, it is crucial for hospitals to possess straightforward and efficient bioanalytical techniques that enable the swift detection of benzodiazepines in biological samples. This review provides a general overview of the different bioanalytical techniques used for the detection and quantification of benzodiazepines in biological samples and emphasizes their suitability for emergency toxicological analyzes.

Designer benzodiazepines versus prescription benzodiazepines: can structural relation predict the next step?

Designer benzodiazepines are a part of the recently discovered abuse synthetic drugs called Novel Psychoactive Substances (NPS) which need to be controlled due to their constantly growing market. Most of them are derived from the medically approved benzodiazepines used nowadays yet, may possess stronger effects, more toxicity, and longer durations of action. Some differences have also been observed in their detection and characteristics, in addition to the variations discovered in postmortem redistribution and drug stability. All these major alterations in features can result from only minor structural modifications. For example, a classic benzodiazepine (BZD) like diazepam only lacks one fluorine atom which exists in its derivatized designer drug, diclazepam, making substantial differences in activity. For this reason, it is essential to study the designer drugs in order to identify their dangers and distinguish them thus rule out their abuse and control the spread of such drugs. This review would highlight the distinct characteristics of some of the most commonly abused designer benzodiazepine analogies in relation to their original prescription BZD compounds.

Comparison of several immunoassays used in drugs of abuse screening: Assessment against gold standard methods and calculation of measurement uncertainty

BACKGROUND

Immunoassays provide simple, powerful and inexpensive screening methods for urine drug screening. Other substances and/or factors may interfere with the test and cause false or positive results. It is essential to understand the differences between methods to be able to evaluate their impact on the results. All evaluated immunoassays were assessed in comparison with GC-MS or LC-MS/MS, which are generally accepted as vigorous confirmation gold standard techniques.

METHODS

CEDIA, DRI, EIA and EMIT II Plus screening immunoassays were evaluated on Beckman-Coulter AU5810 analyser. All results were confirmed using GC-MS or LC-MS/MS methods. Measurement Uncertainty for immunoassays was calculated by using standard deviation multiplied by 1.96 to cover 95% confidence interval of tested samples.

RESULTS

No discrepancy was found between CEDIA and EMIT II Plus for cocaine, methadone, heroin, and benzodiazepines assays. No discrepancy was found between oxycodone DRI assay and Immunalysis enzyme immunoassay (EIA). Cannabinoids EMIT II Plus assay performed better than DRI assay. EMIT II Plus assays for amphetamine and ecstasy performed better than CEDIA amphetamine/ecstasy combined assay. Opiates EMIT II Plus assay performed better than CEDIA assay. Fentanyl Ark EIA method performed slightly better than the DRI method. Buprenorphine CEDIA second-generation assay performed better than CEDIA first-generation assay, EMIT II Plus assay and EMIT II Plus with added Beta-Glucuronidase assay. Measurement Uncertainty for immunoassays was calculated and tabulated.

CONCLUSIONS

This study covered a fundamental gap in available knowledge by evaluating the performance of screening the current new generation of immunoassays methods for drugs of abuse in urine against gold standard methods.

Application of a chemiluminescence immunoassay system and GC/MS for toxicological investigations on skeletonized human remains

Hair, larvae and cardiac muscle, the only biological samples present on a skeletonized human body found in a rural area, were used for forensic toxicological analyses in order to determine possible causes of death. Since no information about the victim or the circumstances of death was available (except for the place where the corpse was found, known to be a gathering place for drug addicts), the first approach for the analysis of non-conventional matrices involved the screening of different classes of active principles, using a chemiluminescence-based screening assay designed for whole blood. The immunoassay test results showed positivity to amphetamines, cocaine and opiates on water/methanol extract from cardiac tissue, larvae and hair samples. Gas chromatography-mass spectrometry (GC/MS) analyses confirmed the immunoassay results, except for amphetamines. The minimal sample preparation (hydration and extraction in an ultrasonic bath), the reduced sample volume required for the analyses, together with the correctness of results as confirmed by GC/MS, showed the suitability of the screening test for forensic applications on non-conventional matrices. Quantitative analyses in GC/MS allowed the cause of death to be ascertained on the basis of the ratio between parent drugs and metabolites.

Analytical Methods Used for the Detection and Quantification of Benzodiazepines

The prescription of psychotropic drugs, especially benzodiazepines (BZDs), occupies a preponderant place in the management of mental illnesses. Indeed, the BZDs have been used in different therapeutic areas including insomnia, anxiety, seizure disorders, or general anesthesia. Unfortunately, these drugs are present in the illegal street market, leading to a lot of drug abuse amongst some addicted users, road insecurity, and suicide. Hence, it has become essential to analyze the BZDs drugs in human biological specimens for drug abuse in forensic sciences. The present review provides a summary of sample preparation techniques (solid-phase extraction and Liquid-liquid phase extraction) and the methods for the detection and quantification of BZDs molecules in the commonly used biological specimens over the ten last years which may potentially lead to better and accurate evaluation of the physiological state of a given person. The commonly used methods for the detection and quantification of BZDs include nuclear magnetic resonance (NMR), chromatography (GC-MS, HPLC, and TLC), immunoassay (ELISA, RIA, LFA, CEDEA, FPIA, and KIMS), and electroanalytical methods (voltammetry and potentiometry).

Development of a simple HPLC-DAD multi-analyte procedure and its application in cases evaluated by the Poison Control Center of São Paulo, Brazil

This work describes a simple approach to overcome challenges in emergency toxicological analysis, using liquid-liquid extraction and high-performance liquid chromatography coupled with a diode-array detector (HPLC-DAD). A rapid procedure has been developed, for the extraction and detection of 19 analytes from the following drug classes: analgesics, benzodiazepines, antidepressants, anticonvulsants and drugs of abuse. These substances are relevant in the context of emergency toxicology in Brazil. The method has been validated according to international guidelines by establishing parameters such as lower limit of quantification, sensitivity, linearity, accuracy and precision. The intra and inter-day precision values, at the lowest concentration levels, have always been less than 20% considering its relative standard deviation. As for accuracy values, these have also been satisfactory (above 81.3%). This method was successfully applied in 201 blood samples from patients with suspected poisoning of the Poison Control Center of São Paulo (PCC-SP), Brazil. Finally, the developed method has shown to be relevant for emergency toxicology due to its high sensitivity and it could be also very useful in both fields of clinical and forensic toxicology.

Analysis of illicit drugs seized in the Province of Florence from 2006 to 2016

Comprehension of illicit drug market's features at local level is useful to plan and to correctly set-up specific informative and contrast activities. In this paper we report trends, purities and consumption estimations of illicit substances available on the Florentine territory from 2006 to 2016. These data were obtained by the analysis of 10,451 samples seized by the Law Enforcement Agencies in case of personal use offence. Analytical procedures consisted in targeted and untargeted analyses by gas chromatography-flame ionization detector, gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry. The most detected substances were: cannabis (78.0%; resin: 51.7%; herb: 26.3%), cocaine (10.4%), opiates (6.6%; heroin: 6.5%; morphine: 0.1%), ketamine (1.4%), amphetamines (1.3%; 3,4-methylenedioxymethamphetamine - MDMA -: 0.7%; methamphetamine: 0.6%; amphetamine: <0.1%) and methadone (1.3%). Cocaine, heroin and methamphetamine purities were higher than their mean values estimated for the Italian and European market, while THC content in cannabis seizures was unexpectedly below the European mean values. Starting from 2015, a total of 5 new psychoactive substances (NPS) were detected in seized material, mainly composed of white powders (pentedrone, 3-methylmethcathinone, 4-fluoroamphetamine, methoxethamine and AB-FUBINACA). Most of the seizures (75.5%) were from young male adults (14-34 years old). These data contribute to highlight new trends in the illicit drug market in the Tuscany area, but also to verify the persistence of old habits of drug consumption, confirming the need for more effective counteraction and prevention plans, especially among young people, where the diffusion of the legal highs is worrisome, also in consideration of the young age and the unconsciousness of the possible health effects.

Improved Clinical Sensitivity of a Reflexive Algorithm to Minimize False-Negative Test Results by a Urine Benzodiazepine Immunoassay Screen

BACKGROUND

Urine drug testing is an essential component of treating patients for chronic pain and/or anxiety and is used to monitor compliance during treatment. A common algorithm is to use an immunoassay as a urine drug screen (UDS), followed by mass spectrometry to confirm all presumptive positive samples. Many UDSs, however, have significant limitations, and false-negative test results can be common due to lack of antibody specificity.

METHODS

Urine samples were screened by a benzodiazepine immunoassay followed by confirmatory testing using LC-MS/MS to determine an initial false-negative test rate for the screen. Attempts to improve the false-negative test rate included hydrolysis before screening and optimization of the absorbance cutoff required for a positive result.

RESULTS

Hydrolysis corrected 41% of false-negative test results in samples containing parent benzodiazepines and/or metabolites but had no effect on samples containing only clonazepam. Of the confirmed false-negative test results, 85% (17 of 20) demonstrated absorbance values between 20 and 100, with 100 being the cutoff for a positive result. Implementing an optimized absorbance cutoff of 20, rather than 100, for a reflexive confirmation testing algorithm decreases the false-negative test rate of detecting benzodiazepine from 47% to 2%.

CONCLUSIONS

Hydrolyzing samples before the benzodiazepine screen provided a modest improvement in the false-negative test rate; however, the screen still missed samples containing clonazepam. Optimization of the absorbance cutoff to reflex samples to LC-MS/MS markedly improved the false-negative test rate for all benzodiazepines.

Development and validation of a sensitive assay for analysis of midazolam, free and conjugated 1-hydroxymidazolam and 4-hydroxymidazolam in pediatric plasma: Application to Pediatric Pharmacokinetic Study

Pharmacokinetic, pharmacodynamic and pharmacogenomic studies of midazolam are currently being performed in critically ill children to find suitable dose regimens. Sensitive assays using small volumes of plasma are necessary to determine the concentrations of midazolam and its respective metabolites in pediatric studies. Midazolam is metabolized to hydroxylated midazolam isomers, which are present as free as well as the corresponding glucuronide conjugates. A high-performance liquid chromatographic method with tandem mass spectrometry has been developed and validated for the quantification of midazolam, and free and total 1-hydroxymidazolam and 4-hydroxymidazolam metabolites in small volumes of plasma. Cleanup consisted of 96-well μ-elution solid phase extraction (SPE). The analytes were separated by gradient elution using a C₁₈ analytical column with a total run time of 5min. Multiple reaction monitoring was employed using precursor to product ion transitions of m/z 326.2→291.3 for midazolam, m/z 342.1→203.0 for 1-hydroxymidazolam, m/z 342.1→325.1 for 4-hydroxymidazolam and m/z 330.2→295.3 for ²H₄-midazolam (internal standard). Since authentic hydroxymidazolamglucuronide standards are not available, samples were hydrolyzed with β-glucuronidase under optimized conditions. Assay conditions were modified and optimized to provide appropriate recovery and stability because 4-hydroxymidazolam was very acid sensitive. Standard curves were linear from 0.5 to 1000ng/mL for all three analytes. Intra- and inter day accuracy and precision for quality control samples (2, 20, 200 and 800ng/mL) were within 85-115% and 15% (coefficient of variation), respectively. Stability in plasma and extracts were sufficient under assay conditions. Plasma samples were processed and analyzed for midazolam, and free 1-hydroxymidazolam and 4-hydroxymidazolam metabolites. Plasma samples that were hydrolyzed with β-glucuronidase were processed and analyzed for midazolam, and total 1-hydroxymidazolam and 4-hydroxymidazolam metabolites under the same assay conditions. The difference in concentration between the total and free hydroxymidazolam metabolites provided an estimate of conjugated hydroxymidazolam metabolites. The combination of 96-well μ-elution SPE and LC-MS/MS allows reliable quantification of midazolam and its metabolites in small volumes of plasma for pediatric patients. This assay is currently being successfully utilized for analysis of samples from ongoing clinical trials.

A novel screening method for 64 new psychoactive substances and 5 amphetamines in blood by LC-MS/MS and application to real cases

Identification and quantification of new psychoactive substances (NPS), both in biological and non-biological samples, represent a hard challenge for forensic toxicologists. NPS are increasingly emerging on illegal drug market. Many cases of co-consumption of NPS and other substances have also been reported. Hence, the development of analytical methods aiming at the detection of a broad-spectrum of compounds (NPS and "traditional" drugs) could be helpful. In this paper, a fully validated screening method in blood for the simultaneous detection of 69 substances, including 64 NPS (28 synthetic cannabinoids, 19 synthetic cathinones, 5 phenethylamines, 3 indanes, 2 piperazines, 2 tryptamines, 2 phencyclidine, methoxetamine, ketamine and its metabolite) and 5 amphetamines (amphetamine, methamphetamine, MDMA, MDA, 3,4-methylenedioxy-N-ethylamphetamine - MDEA-) by a dynamic multiple reaction monitoring analysis through liquid chromatography - tandem mass spectrometry (LC-MS/MS) is described. This method is very fast, easy to perform and cheap as it only requires the deproteinization of 200μL of blood sample with acetonitrile. The chromatographic separation is achieved with a C18 column. The analysis is very sensitive, with limits of quantification ranging from 0.1 to 0.5ng/mL. The method is linear from 1 to 100ng/mL and the coefficient of determination (R(2)) was always above 0.9900. Precision and accuracy were acceptable at any quality control level and recovery efficiency range was 72-110%. Matrix effects did not negatively affect the analytical sensitivity. This method was successfully applied to three real cases, allowing identification and quantification of: mephedrone and methamphetamine (post-mortem); ketamine, MDMA and MDA (post-mortem); AB-FUBINACA (ante-mortem).

In vivo detection of the new psychoactive substance AM-694 and its metabolites

AM-694 or 1-(5-fluoropentyl)-3-(2-iodobenzoyl)indole is a synthetic cannabinoid that acts as a selective and a powerful agonist for CB1 receptor, inducing cannabinoid-like effects (euphoria, sedation, hallucinations and anxiety). Its spread, like for other synthetic cannabinoids, has increased in recent years and many web sources freely supply these kinds of new drugs. It can be taken by smoking or through oral consumption. A 25-years-old man was hospitalized at the local hospital following a major trauma after ingestion of alcohol and an unknown pill. Urine and blood samples were sent to our Forensic Toxicology Division to investigate on possible substance abuse. A general unknown screening of biological samples, extracted by liquid-liquid extraction (ethylacetate and dichloromethane) in basic, acidic and neutral conditions, was achieved to verify the presence of drugs of abuse and/or their metabolites, both in gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). For the quantification of AM-694, urine was extracted by solid phase extraction (SPE) on a Bond Elut Certify cartridge; an acidic hydrolysis (HCl 30%, 95°C, 60min) was necessary before liquid-liquid extraction of metabolites. For the detection of benzodiazepines and their metabolites, an enzymatic hydrolysis was applied (β-glucuronidase, pH 4.5, 50°C, 18h). Quantification of AM-694 (internal standard AM-2201), midazolam and α-hydroxymidazolam (internal standard halazepam) were performed by LC-MS/MS analysis in multiple reaction monitoring ([M+H](+): m/z 436→190, 272, AM-694; m/z 360→155, 127, AM-2201; m/z 326→291, 223, midazolam; m/z 342→168, 203, α-hydroxymidazolam; m/z 353→241, 222, halazepam). The general unknown screening revealed the presence of AM-694 (urine sample) and benzodiazepines (urine and blood). The concentration of AM-694, obtained by LC-MS/MS, was 0.084μg/L. Midazolam and α-hydroxymidazolam were detected in urine (0.97 and 74.58μg/L, respectively) and in blood (34.84 and 23.15μg/L, respectively). Qualitative information about the AM-694 metabolites was obtained by LC-MS/MS in selected-ion monitoring for the putative [M+H](+) ions: m/z 448, carboxylated metabolite; m/z 434, defluorinated metabolite; quantification was not possible since reference standards are not available. Our report is the first case of detection of AM-694 and its metabolites in human biological fluids in Italy. For this reason, this case constitutes a first worrisome alarm about the spread of this substance.

A simple extraction and LC-MS/MS approach for the screening and identification of over 100 analytes in eight different matrices

In the present study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) multi-analyte approach using one single work-up approach in whole blood, plasma, serum, post-mortem blood, liver tissue, gastric content, hair, and urine was developed for fast target screening and reliable identification of 130 analytes often requested in clinical and forensic toxicology. Samples (500 μL each) of whole blood, plasma, serum, post-mortem blood, tissue (homogenized 1 + 4 with water), as well as 3 g of distilled gastric contents, 1 mL of urine, or 20 mg of pulverized hair were extracted at different pH values with an diethyl ether-ethyl acetate mixture (1:1). Separation and identification were performed using LC-QTRAP with electrospray ionization in positive mode. For identification 1 scheduled multi-reaction-mode (sMRM) method with 390 transitions was developed covering benzodiazepines, Z-drugs, antidepressants, neuroleptics, opioids, new synthetic drugs, and phosphodiesterase type 5 inhibitors. For positive sMRM transitions with intensities exceeding 5000 cps, dependent scans (EPI scan collision energy, 35 eV, collision energy spread, 15 eV) were performed for library search using our in-house library. The method was developed with respect to selectivity, matrix effects, recovery, process efficiency, limit of detection, and applicability. The simple work-up procedure was suitable for all biosamples with exception of urine in respect to low concentrated analytes, which showed median recovery values of 59%. The method was selective for 130 analytes in all 8 biosamples. For 106 analytes, the limit of detection in whole blood, plasma, and serum was lower than the lowest therapeutic concentration listed in blood level lists.

Detectability of new psychoactive substances, 'legal highs', in CEDIA, EMIT, and KIMS immunochemical screening assays for drugs of abuse

The increasing number of new psychoactive substances made available for recreational drug use has created a challenge for clinical toxicology and drug testing laboratories. As a consequence, the routine immunoassay drug testing may become less effective due to an increased occurrence of false negative and false positive screening results. This work aimed to extend the knowledge about analytical cross-reactivity of new substances in selected CEDIA, EMIT, and KIMS immunoassays for drugs-of-abuse screening. Urine standards were prepared by spiking blank urine with 45 new substances. Authentic urine samples from intoxication cases identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) were also studied. Several new psychoactive substances were demonstrated to display cross-reactivity in the immunoassays. CEDIA Amphetamine/Ecstasy and EMIT d.a.u. Amphetamine Class tests showed the highest reactivity towards the new drugs, which was expected since many have amphetamine-like structure and activity. In the samples from authentic cases, five new substances displayed 100% detection rate in the CEDIA Amphetamine/Ecstasy test. In conclusion, cross-reactivity data in routine urine drug screening immunoassays for a number of new psychoactive substances not studied before were reported. In both spiked and authentic urine samples, some new substances showed significant cross-reactivity and are thus detectable in the routine screening methods.