Ultrasound-assisted low-density solvent dispersive liquid–liquid microextraction for the determination of 4 designer benzodiazepines in urine samples by gas chromatography–triple quadrupole mass spectrometry

Recent Advances in Dispersive Liquid-Liquid Microextraction for Pharmaceutical Analysis

Sample clean-up and pre-concentration are critical components of pharmaceutical analysis. The dispersive liquid-liquid microextraction (DLLME) technique is widely recognized as the most effective approach for enhancing overall detection sensitivity. While various DLLME modes have been advanced in pharmaceutical analysis, there need to be more discussions on pre-concentration techniques specifically developed for this field. This review presents a comprehensive overview of the different DLLME modes used in pharmaceutical analysis from 2017 to May 2023. The review covers the principles of DLLME, the factors affecting microextraction, the selected applications of different DLLME modes, and their advantages and disadvantages. Additionally, it focuses on multi-extraction strategies employed for pharmaceutical analysis.

Quantification of sedative-hypnotics in human urine and plasma via polystyrene-based solid phase extraction-LC-MS/MS analysis

Owing to the adverse effects of the overuse of common sedative-hypnotics on human health, the development of an efficient analytical method for the detection of drugs in clinical emergencies and forensic science is significant. Although conventional analytical methods, such as immunoassay, liquid chromatography (LC), gas chromatography, and mass spectrometry (MS) are reliable, they exhibit drawbacks such low-throughput screening and high costs. Thus, in this study, we developed a novel high-throughput method consisting of a polystyrene-based solid phase extraction (SPE) and an LC with tandem MS analysis for the detection of drugs in biological samples and investigated its precision and reliability via the detection of twelve sedative-hypnotics in human urine and plasma samples. Good linear relationship (r ≥ 0.99) were achieved within the concentration range of 0.1-20 ng/mL for the 12 analytes in urine samples. Whereas, in the plasma samples, the correlation coefficient was greater than 0.99 in the concentration range 1-100 ng/mL for lorazepam and clonazepam and in the range 0.5-100 ng/mL for the remaining analytes. The intra- and inter-day precision, autosampler and freeze-thaw stabilities, and lower limit of quantitation (LLOQ) for all twelve analytes in the urine and plasma samples were favorable. Furthermore, sedative-hypnotics were detected in clinical samples obtained from the Hebei General Hospital using this method. These results indicated that the analytical method proposed in this study can be effectively applied in toxicology screening and drug abuse monitoring.The method developed in this study could be applied in clinical and forensic toxicology laboratories for sedative-hypnotic drug screening, providing support for drug abuse monitoring and clinical diagnosis.

Detection, quantification and degradation kinetic for five benzodiazepines using VAUS-ME-SFO/LC-MS/MS method for water, alcoholic and non-alcoholic beverages

Benzodiazepines can make victims more docile, they are frequently used in drug-facilitated crimes, such as robberies and sexual assaults. Therefore, it is essential to develop techniques for determining whether these chemicals are present in relation with illegal activity is crucial. Therefore, to determine the presence of five benzodiazepines (alprazolam, clonazepam, diazepam, lorazepam, and oxazepam) in water, alcoholic beverages, and non-alcoholic beverages, a simple and direct, miniaturized, and effective vortex assisted ultrasound based microextraction using solidification of floating organic droplets (VAUS-ME-SFO) in combination with LC-MS/MS was developed. 1-Undecanol and acetonitrile, respectively, served as the extractant and disperser solvents. Many other parameters affect the efficiency of the developed analytical procedure VAUS-ME-SFO/LC-MS/MS. These parameters were optimized using Plackett Burman Design and Central Composite Design to obtain reliable results. The optimum conditions for the extraction were: 10.0 mL of sample; 180 μL acetonitrile, as a dispersive solvent; 200 μL of 1-undecanol, as an extraction solvent; pH 7; 105 s of vortex agitation; 120 s of ultrasonication application and 3 min of centrifugation at 7000 rpm. The benzodiazepines were separated by a chromatographic separation technique carried out by a UPLC system consisting of a binary mobile phase. The solvent system comprises of 0.1% Formic acid in Milli-Q (Solvent A) and 0.1% Formic acid in ACN (Solvent B) with a gradient flow of 3.5 min total analysis time. Under the optimized conditions, the calibration curve was studied in the range of 0.124-7.810 ng mL^-1. The regression correlation coefficient (R²) value of all targeted analytes ranges from 0.993 to 0.999. The LOD and LOQ of VAUS-ME-SFO methods using LC-MS/MS analysis range from 0.316 to 0.968 ng mL^-1 and 1.055-3.277 ng mL^-1 respectively. The repeatability within a day varied from 0.6 to 3.5%, and the reproducibility across days varied from 2.2 to 6.3%. The recoveries ranges for water, alcoholic and non-alcoholic beverages from 70.77 to 114.53%, 63.20-102.21% and 66.23-113.28% respectively. Further, the degradation kinetics was studied to establish the half-life of each targeted analyte in the matrix undertaken in the study. The water samples were classified based on their BDZs residues. This implies that the more health care and anthropogenic activity, the more the BDZs residue will be in water samples.

Determination of amphetamines, ketamine and their metabolites in hair with high-speed grinding and solid-phase microextraction followed by LC-MS

A novel hair sample pre-treatment method based on high-speed grinding and solid-phase microextraction (SPME) had been applied for the determination of amphetamines, ketamine and their metabolites in hair samples by liquid chromatography-mass spectrometry (LC-MS). A 20 mg sample of hair was ground with 2 mL of saturated sodium carbonate solution using a high-efficiency hair grinder with 70 Hz oscillation for 2 min at 4 °C. After centrifuging, 1.5 mL of the supernatant was transferred and treated with SPME by direct immersion (DI-SPME). The target analytes extracted by fibre were desorbed and analysed using LC-MS. Under the optimum conditions, a recovery of 90.2%–95.8% was obtained for all analytes. The analytical method was linear for all analytes in the range from 0.2 to 10 ng/mg with the correlation coefficient ranging from 0.9985 to 0.9993. The detection limits for all analytes were estimated to be 0.067 ng/mg. The accuracy (mean relative error) was within ±6.9% and the precision (relative standard error) was less than 6.8%. The combination of high-speed grinding of hair and SPME had the advantages of being easy to perform, environment-friendly and high in detection sensitivity. The proposed method offered an alternative analytical approach for the sensitive detection of drugs in hair samples for forensic purposes.

Key Points

The SPME was involved for the determination of drugs in hair with LC-MS.

The hair high-speed grinding combined with SPME was firstly developed.

Good linearity, sensitivity, recovery and precision were achieved.

Dispersive liquid-liquid microextraction of 11-nor-Δ9-tetrahydrocannabinol-carboxylic acid applied to urine testing

Aim: THC-COOH is the major metabolite of Δ⁹-tetrahydrocannabinol commonly tested in urine to determine cannabis intake. In this study, a method based on dispersive liquid-liquid microextraction was developed for testing THC-COOH in urine. Materials & methods: Hydrolyzed urine specimens were extracted via dispersive liquid-liquid microextraction with acetonitrile (disperser solvent) and chloroform (extraction solvent). Derivatization was performed with N,O-Bis(trimethylsilyl)trifluoroacetamide with 1% trichloro(chloromethyl)silane. Analysis was performed by GC-MS/MS. Results: The method showed acceptable linearity (5-500 ng/ml), imprecision (<10.5%) and bias (<4.9%). Limits of detection and quantitation were 1 and 5 ng/ml, respectively. Twenty-four authentic samples were analyzed, with 22 samples being positive for THC-COOH. Conclusion: The proposed method is more environmentally friendly and provided good sensitivity, selectivity and reproducibility.

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.

Recent applications of microextraction sample preparation techniques in biological samples analysis

Analysis of biological samples is affected by interfering substances with chemical properties similar to those of the target analytes, such as drugs. Biological samples such as whole blood, plasma, serum, urine and saliva must be properly processed for separation, purification, enrichment and chemical modification to meet the requirements of the analytical instruments. This causes the sample preparation stage to be of undeniable importance in the analysis of such samples through methods such as microextraction techniques. The scope of this review will cover a comprehensive summary of available literature data on microextraction techniques playing a key role for analytical purposes, methods of their implementation in common biological samples, and finally, the most recent examples of application of microextraction techniques in preconcentration of analytes from urine, blood and saliva samples. The objectives and merits of each microextration technique are carefully described in detail with respect to the nature of the biological samples. This review presents the most recent and innovative work published on microextraction application in common biological samples, mostly focused on original studies reported from 2017 to date. The main sections of this review comprise an introduction to the microextraction techniques supported by recent application studies involving quantitative and qualitative results and summaries of the most significant, recently published applications of microextracion methods in biological samples. This article considers recent applications of several microextraction techniques in the field of sample preparation for biological samples including urine, blood and saliva, with consideration for extraction techniques, sample preparation and instrumental detection systems.

Overview of the major classes of new psychoactive substances, psychoactive effects, analytical determination and conformational analysis of selected illegal drugs

The misuse of psychoactive substances is attracting a great deal of attention from the general public. An increase use of psychoactive substances is observed among young people who do not have enough awareness of the harmful effects of these substances. Easy access to illicit drugs at low cost and lack of effective means of routine screening for new psychoactive substances (NPS) have contributed to the rapid increase in their use. New research and evidence suggest that drug use can cause a variety of adverse psychological and physiological effects on human health (anxiety, panic, paranoia, psychosis, and seizures). We describe different classes of these NPS drugs with emphasis on the methods used to identify them and the identification of their metabolites in biological specimens. This is the first review that thoroughly gives the literature on both natural and synthetic illegal drugs with old known data and very hot new topics and investigations, which enables the researcher to use it as a starting point in the literature exploration and planning of the own research. For the first time, the conformational analysis was done for selected illegal drugs, giving rise to the search of the biologically active conformations both theoretically and using lab experiments.

Simultaneous determination of 10 new psychoactive piperazine derivatives in urine using ultrasound-assisted low-density solvent dispersive liquid-liquid microextraction combined with gas chromatography-tandem mass spectrometry

With the rapid development of synthetic drugs, novel piperazine derivatives, as an increasingly important class of new psychoactive substances (NPS), have attracted global attention owing to their increasing demand in the illicit drug market. In this study, ten piperazine derivatives were analyzed in urine samples after pre-treatment with ultrasound-assisted low-density solvent dispersive liquid-liquid microextraction (UA-LDS-DLLME) combined with gas chromatography-tandem mass spectrometry (GC-MS/MS). This simple approach involved the use of urine samples (1 mL) adjusted to pH 12, which was added to 100 µL of n-hexane and subjected to ultrasonication for 3 min to completely disperse the sample in the n-hexane solution. The resulting turbid suspension was centrifuged at 10,000 rpm for 3 min, and the supernatant was extracted and analyzed using GC-MS/MS. Under the optimized conditions presented in this study, the linear relationship between the analytes was good within 10-1500 ng/mL, and the correlation coefficient (r) was between .9914 and .9983. The limit of detection (LOD) was 0.3-2 ng/mL (S/N = 3), and the lower limit of quantification (LLOQ) was 10 ng/mL (S/N = 10) with the recovery of the analytes of interest from the spiked samples being 76.3%-93.3%. This method has been used to analyze real-world samples; our study shows that the UA-LDS-DLLME approach can be used for rapid analysis while consuming minimal solvent for the simultaneous determination of a range of analytes. This method has the potential for use in clinical analyses and forensic toxicology.

An analytical strategy for designer benzodiazepines and Z-hypnotics determination in plasma samples using ultra-high performance liquid chromatography/tandem mass spectrometry after microextraction by packed sorbent

The illicit market for new psychoactive substances (NPS) is continuously growing. Designer benzodiazepines (DBZD) and Z-hypnotics are increasingly being used for self-medication or recreational purposes. The limited regulation and little biological information available about NPS have raised the need for analytical methods capable of extracting and quantifying them in human biological fluids. In this work, a procedure based on microextraction by packed sorbent (MEPS) in combination with ultra-high performance liquid chromatography and tandem mass spectrometry (UHPLC-MS/MS) has been developed to determine the designer benzodiazepines (clonazolam, deschloroetizolam, nifoxipam, flubromazolam and meclonazepam), and the Z-hypnotics (zolpidem, zaleplon and zopiclone) in plasma. A 3³4²//16 asymmetric screening design was used to study extraction variables such as the type and volume of eluent, pH, number of extraction cycles, volume of washing solvent and type of sorbent. The ensuing analytical method was validated in terms of linearity by standard addition calibration curves at eight different analyte concentration levels from 0.5-500 ng mL^-1. R² values, limits of detection (LOD) and limits of quantification (LOQ) fell in the ranges 0.9900-0.9988, 0.5-5 ng mL^-1 and 1-10 ng mL^-1. Intra and interday precision expressed as relative standard deviations, were < 10.6 % and process efficiency ranged from 63 to 117 % for the quality control samples. The proposed method detected zolpidem and various other benzodiazepines in plasma samples from overdoses cases.

Recent bionalytical methods for the determination of new psychoactive substances in biological specimens

One of the problems associated with the consumption of new psychoactive substances is that in most scenarios of acute toxicity the possibility of quick clinical action may be impaired because many screening methods are not responsive to them, and laboratories are not able to keep pace with the appearance of new substances. For these reasons, developing and validating new analytical methods is mandatory in order to efficiently face those problems, allowing laboratories to be one step ahead. The goal of this work is to perform a critical review regarding bionalytical methods that can be used for the determination of new psychoactive substances (phenylethylamines, cathinones, synthetic cannabinoids, opioids, benzodiazepines, etc), particularly concerning sample preparation techniques and associated analytical methods.

MASS SPECTROMETRY ANALYSIS OF DRUGS OF ABUSE: CHALLENGES AND EMERGING STRATEGIES

Mass spectrometry has been the "gold standard" for drugs of abuse (DoA) analysis for many decades because of the selectivity and sensitivity it affords. Recent progress in all aspects of mass spectrometry has seen significant developments in the field of DoA analysis. Mass spectrometry is particularly well suited to address the rapidly proliferating number of very high potency, novel psychoactive substances that are causing an alarming number of fatalities worldwide. This review surveys advancements in the areas of sample preparation, gas and liquid chromatography-mass spectrometry, as well as the rapidly emerging field of ambient ionization mass spectrometry. We have predominantly targeted literature progress over the past ten years and present our outlook for the future. © 2020 Periodicals, Inc. Mass Spec Rev.

Validation of an LC-MS/MS Method for the Quantification of 13 Designer Benzodiazepines in Blood

The misuse of designer benzodiazepines, as an alternative to prescription benzodiazepines and for drug-facilitated sexual assaults, has emerged as a growing threat, due in part to the ease of purchasing these drugs on the internet at low prices. Causing concern for safety is the lack of dosage information resulting in users self-medicating, often leading to unintended overdoses, coma or death at higher doses. With limited published data regarding the quantification of designer benzodiazepines in forensic cases, a method was validated for the determination of 13 designer benzodiazepines in postmortem blood, to add to the in-house method that already included a limited number of common designer benzodiazepines. The developed method included 3-hydroxyphenazepam, clobazam, clonazolam, delorazepam, deschloroetizolam, diclazepam, flualprazolam, flubromazepam, flubromazolam, flunitrazolam, meclonazepam, nifoxipam and pyrazolam in 0.5 mL postmortem blood using liquid chromatography-tandem mass spectrometry. The analytes were treated with solid phase extraction before undergoing separation on a C18 column and analyzed on the mass spectrometer in electrospray positive mode using multiple reaction monitoring. The linear range of the calibration curve was 1-200 ng/mL and up to 500 ng/mL for 3-hydroxyphenazepam, clobazam, flubromazepam and pyrazolam. The limits of detection and quantitation were 0.5 ng/mL (signal-to-noise ratio >3) and 1 ng/mL, respectively. The calculated bias, intra-day imprecision, relative standard deviation (RSD) and inter-day imprecision RSD were ±12%, 3-20% and 4-21%. Matrix effects ranged from -52% to 33% with RSD values ranging from 3-20%, indicating consistent effects throughout multiple sources. Recovery ranged from 35 to 90%, where only two compounds were <50%. Other parameters tested included carryover, stability, interference and dilution integrity, which all yielded acceptable results. With the application of this method to blood specimens from the New York City Office of Chief Medical Examiner, this validated method proved to be simple, reproducible, sensitive and robust.

Urine analysis of 28 designer benzodiazepines by liquid chromatography-high-resolution mass spectrometry

Hundreds of new psychoactive substances (NPS) covering most drugs-of-abuse classes have been introduced to the recreational drug market in recent years. One class of NPS drugs that has become more common recently is "designer" benzodiazepines. Due to a close structural resemblance with prescription benzodiazepines, some of these substances may elicit a positive response (i.e. cross react) in immunoassay screening. Consequently, it is increasingly important to include NPS benzodiazepines during method confirmation to ensure accurate identification of closely-related compounds as well as detection of the benzodiazepines themselves. Here, we present our efforts to develop a screening and confirmation method for detection of 28 NPS benzodiazepines in urine using reversed-phase liquid chromatographic separation in combination with high-resolution mass spectrometry (LC-HRMS). MS was performed in positive electrospray mode on a Thermo Fischer Scientific Q Exactive Orbitrap instrument using either full scan (for screening) or parallel reaction monitoring (for confirmation). We found the lower quantification limit of the method to range from 5 to 50 ng/mL. Analytical precision and accuracy were ≤15% for both screening and confirmation for all except one analyte. The method was used to analyze patient urine samples from routine drug testing and samples from acute intoxication cases presenting in emergency wards. Altogether, 16 of the 28 benzodiazepines (i.e., clobazam, clonazolam, deschloroetizolam, diclazepam, estazolam, etizolam, flubromazepam, flubromazolam, flunitrazolam, 3-hydroxyflubromazepam, 3-hydroxyphenazepam, ketazolam, meclonazepam, metizolam, nifoxipam, and pyrazolam) were detected in the urine samples. The results from patient sample analysis indicate a high prevalence of NPS benzodiazepine use, emphasizing the importance of including novel drugs of abuse in drug testing menus.

Quantitation of Benzodiazepines and Metabolites in Urine by Liquid Chromatography–Tandem Mass Spectrometry

Background

Benzodiazepines (BZDs) are central nervous system depressants that are prescribed to prevent seizures, manage anxiety, or help sleep. When misused, BZDs can lead to addiction and sometimes cause death. Measurement of BZDs in urine is used to identify their use, especially in pain management settings. LC-MS/MS is preferred for these measurements because of its high sensitivity and specificity. Here, we report an LC-MS/MS assay for measuring 7 BZDs and metabolites in urine.

Methods

Urine sample was incubated at 60 °C for 30 min after addition of internal standards and a β-glucuronidase solution. After centrifugation, the supernatant was diluted with methanol and water before being injected onto a C18 analytical column in an LC-MS/MS system for quantification. The analytical time between injections was 4.35 min. The analytes included 7-aminoclonazepam, α-hydroxyalprazolam, α-hydroxytriazolam, oxazepam, lorazepam, nordiazepam, and temazepam.

Results

The lower limit of quantification ranged from 30 ng/mL to 50 ng/mL with an analytical recovery &gt;80% for all 7 analytes. Total CV was &lt;10% for all analytes (3 concentration levels of 100, 2500, and 5000 ng/mL; n = 30 each). This method had 100% agreement with a GC-MS method offered by an independent laboratory for negative urine samples. For the positive urine samples, this method showed a strong correlation (R &gt; 0.96) with the GC-MS method.

Conclusions

The LC-MS/MS assay allows accurate and precise measurement of 7 BZDs and metabolites in a single analytical run with a short analytical run time and broad measuring ranges.

Designer Benzodiazepines: Another Class of New Psychoactive Substances

Benzodiazepines have been introduced as medical drugs in the 1960s. They replaced the more toxic barbiturates, which were commonly used for treatment of anxiety or sleep disorders at the time. However, benzodiazepines show a high potential of misuse and dependence. Although being of great value as medicines, dependence to these drugs is a concern worldwide, in part due to overprescription and easy availability. Therefore, the phenomenon of benzodiazepines sold via Internet shops without restrictions at low prices is alarming and poses a serious threat to public health. Most of these compounds (with the exception of, e.g., phenazepam and etizolam) have never been licensed as medical drugs in any part of the world and are structurally derived from medically used benzodiazepines. Strategies of clandestine producers to generate new compounds include typical structural variations of medically used 1,4-benzodiazepines based on structure-activity relationships as well as synthesis of active metabolites and triazolo analogs of these compounds. As they were obviously designed to circumvent national narcotics laws or international control, they can be referred to as "designer benzodiazepines." The majority of these compounds, such as diclazepam, clonazolam, and nitrazolam, have been described in scientific or patent literature. However, little is known about their pharmacological properties and specific risks related to their use. This chapter describes the phenomenon of designer benzodiazepines and summarizes the available data on pharmacokinetics and pharmacodynamics as well as analytical approaches for their detection.