A fast liquid chromatography-tandem mass spectrometry method for determining benzodiazepines and analogues in urine. Validation and application to real cases of forensic interest

Rapid detection of 10 benzodiazepines and metabolites in blood and urine using DART-MS/MS

Benzodiazepines are essential screening targets for common sleeping and sedative drugs used in forensic toxicology. Direct analysis in real-time tandem mass spectrometry was used to rapidly identify 10 benzodiazepines and related metabolites in the blood and urine. The related direct analysis in real-time tandem mass spectrometry parameters were optimized. A liquid-liquid extraction method using ethyl acetate as the extraction solvent was used for sample preparation. The established method was validated and tested on case specimens. The limits of detection of this method ranged from 0.2 to 20 ng/mL and the limits of quantification from 1 to 50 ng/mL. The recoveries ranged from 78.8% to 114%, and the matrix effects were in the range of -21.2% to 17.9%. The precision and repeatability at high and medium concentrations did not exceed 14.6%, and the limit of quantification did not exceed 18.2%, indicating a desirable linear relationship. The established method was used to determine blood and urine specimens from authentic cases, and promising results were obtained.

A validated dilute-and-shoot LC-MS-MS urine screening for the analysis of 95 illicit drugs and medicines: Insights from clinical and forensic Brazilian cases

Urine toxicological analysis is a relevant tool in both clinical and forensic scenarios, enabling the diagnosis of acute poisonings, elucidation of deaths, verification of substance use in the workplace and identification of drug-facilitated crimes. For these analyses, the dilute-and-shoot technique associated with liquid chromatography coupled with tandem mass spectrometry (LC-MS-MS) is a promising alternative since it has demonstrated satisfactory results and broad applicability. This study developed and validated a comprehensive LC-MS-MS screening method to analyze 95 illicit drugs and medicines in urine samples and application to clinical and forensic Brazilian cases. The dilute-and-shoot protocol was defined through multivariate optimization studies and was set using 100 µL of sample and 300 µL of solvent. The total chromatographic run time was 7.5 min. The method was validated following the recommendations of the ANSI/ASB Standard 036 Guideline. The lower limits of quantification varied from 20 to 100 ng/mL. Within-run and between-run precision coefficient of variations% were <20%, and bias was within ± 20%. Only 4 of the 95 analytes presented significant ionization suppression or enhancement (>25%). As proof of applicability, 839 urine samples from in vivo and postmortem cases were analyzed. In total, 90.9% of the analyzed samples were positive for at least one substance, and 78 of the 95 analytes were detected. The most prevalent substances were lidocaine (40.2%), acetaminophen (38.0%) and benzoylecgonine (31.5%). The developed method proved to be an efficient and simplified alternative for analyzing 95 therapeutic and illicit drugs in urine samples. Additionally, the results obtained from sample analysis are essential for understanding the profile of Brazilian substance use, serving as a valuable database for the promotion of health and safety public policies.

Selective Extraction of Diazepam and Its Metabolites from Urine Samples by a Molecularly Imprinted Solid-Phase Extraction (MISPE) Method

In this research, a molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization using oxazepam (OZ) as a template molecule and was subsequently applied as a selective sorbent for the extraction of diazepam (DZP) and its metabolites in urine samples using an SPE cartridge. OZ, temazepam (TZ), nordiazepam (NZ) and DZP were analyzed in the final extracts by high-performance liquid chromatography with diode array detection (HPLC-DAD). The SPE extraction steps were optimized, and the evaluation of an imprinting factor was carried out. The selectivity of the method for OZ versus structurally related benzodiazepines (BZDs), such as bromazepam (BRZ), tetrazepam (TTZ) and halazepam (HZ), was investigated. Under the optimum conditions, the proposed methodology provided good linearity in the range of 10-1500 ng/mL, with limit of detection values between 13.5 and 21.1 ng/mL and recovery levels for DZP and its metabolites from 89.0 to 93.9% (RSD ≤ 8%) at a concentration level of 1000 ng/mL. The proposed method exhibited good selectivity, precision and accuracy and was applied to the analysis of urine samples from a real case of DZP intake.

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.

A method for improved detection of 8-isoprostaglandin F2α/β and benzodiazepines in wastewater

Wastewater-based epidemiology is a tool incorporating biomarker analysis that can be used to monitor the health status of a population. Indicators of health include endogenous oxidative stress biomarkers and hormones, or exogenous such as alcohol and nicotine. 8-Iso-prostaglandin F_2α/β is a biomarker of endogenous metabolism that can be used to measure oxidative stress in a community. Benzodiazepines are a harmful subclass of anxiolytics either prescribed or sourced illegally. The analysis of oxidative stress markers and uptake of benzodiazepines in wastewater may provide information about distress in the community. A method has been applied to detect 8-isoPGF_2α/β and the illicit benzodiazepines clonazolam, flubromazolam and flualprazolam in addition to other prescribed benzodiazepines in wastewater. These substances have been sold as counterfeit pharmaceutical products, such as Xanax, which was formulated to include alprazolam. Deconjugation was initially performed on wastewater samples, followed by liquid-liquid extraction for isoprostanes and solid phase extraction for benzodiazepines to determine the total levels of these analytes. Limits of quantification were in the range of 0.5-2 ng/L for all the analytes except 8-isoPGF_2α/β which was 50 ng/L. Stability, recovery and matrix effect studies were also conducted. Finally, this method was applied to influent wastewater from South Australia which showed the prevalence of 8-isoPGF_2α/β and benzodiazepines.

The Evolution Toward Designer Benzodiazepines in Drug-Facilitated Sexual Assault Cases

Drug-facilitated sexual assault (DFSA) is a crime where the victim is unable to provide sexual consent due to incapacitation resulting from alcohol or drug consumption. Due to the large number of substances possibly used in DFSA, including illicit, prescription and over-the-counter drugs, DFSA faces many toxicological challenges. Benzodiazepines (BZDs) are ideal candidates for DFSA, as they are active at low doses, have a fast onset of action and can be easily administered orally. The last decade has seen the emergence of designer benzodiazepines (DBZDs), which show slight modifications compared with BZDs and similar pharmacological effects but are not controlled under the international drug control system. DBZDs represent an additional challenge due to the number of new entities regularly appearing in the market, their possibly higher potency and the limited knowledge available on their pharmacokinetic and pharmacodynamics properties. Many BZDs and DBZDs have a short half-life, leading to rapid metabolism and excretion. The low concentrations and short time windows for the detection of BZD in body fluids require the use of highly sensitive analysis methods to enable the detection of drugs and their respective metabolites. This review discusses the current state of the toxicological analysis of BZDs and DBZDs in forensic casework and their pharmacokinetic properties (i.e., absorption, distribution, metabolism, and elimination), as well as their analysis in biosamples typically encountered in DFSA (i.e., blood, urine and hair).

Untargeted Metabolomics in Forensic Toxicology: A New Approach for the Detection of Fentanyl Intake in Urine Samples

The misuse of fentanyl, and novel synthetic opioids (NSO) in general, has become a public health emergency, especially in the United States. The detection of NSO is often challenged by the limited diagnostic time frame allowed by urine sampling and the wide range of chemically modified analogues, continuously introduced to the recreational drug market. In this study, an untargeted metabolomics approach was developed to obtain a comprehensive "fingerprint" of any anomalous and specific metabolic pattern potentially related to fentanyl exposure. In recent years, in vitro models of drug metabolism have emerged as important tools to overcome the limited access to positive urine samples and uncertainties related to the substances actually taken, the possible combined drug intake, and the ingested dose. In this study, an in vivo experiment was designed by incubating HepG2 cell lines with either fentanyl or common drugs of abuse, creating a cohort of 96 samples. These samples, together with 81 urine samples including negative controls and positive samples obtained from recent users of either fentanyl or "traditional" drugs, were subjected to untargeted analysis using both UHPLC reverse phase and HILIC chromatography combined with QTOF mass spectrometry. Data independent acquisition was performed by SWATH in order to obtain a comprehensive profile of the urinary metabolome. After extensive processing, the resulting datasets were initially subjected to unsupervised exploration by principal component analysis (PCA), yielding clear separation of the fentanyl positive samples with respect to both controls and samples positive to other drugs. The urine datasets were then systematically investigated by supervised classification models based on soft independent modeling by class analogy (SIMCA) algorithms, with the end goal of identifying fentanyl users. A final single-class SIMCA model based on an RP dataset and five PCs yielded 96% sensitivity and 74% specificity. The distinguishable metabolic patterns produced by fentanyl in comparison to other opioids opens up new perspectives in the interpretation of the biological activity of fentanyl.

Identification and characterization of new impurities in zopiclone tablets by LC-QTOF-MS

Zopiclone, a non-benzodiazepine hypnotic, is the first-line treatment for insomnia. The quality and stability of zopiclone tablets directly affects its efficacy and safety. However, the impurity investigation in zopiclone tablets remain incomplete. In this study, the accelerated and long-term stabilities of zopiclone tablets, as well as the stability characteristics under thermal and photolytic conditions were evaluated according to the ICH guidelines. In addition, a sensitive and specific LC-QTOF-MS method was developed for the separation and identification of all the impurities in zopiclone tablets and its stability test samples. Nine impurities were found in the test samples, five among them have not been reported before. Based on the accurate mass and elemental compositions of the parent and product ions obtained, the structures of all the detected impurities were identified. Combined with the formulation composition analysis and stability studies, the origins and the formation mechanisms of these impurities were elucidated. The obtained results are useful for the establishment of the optimum formulation, storage condition, manufacturing processes and quality control of zopiclone tablets.

Interference Free Method for Determination of Benzodiazepines in Urine Based on Restricted Access Supramolecular Solvents and LC-MS/MS

Supramolecular solvents with restricted access properties (SUPRAS-RAM) are proposed as a new approach for integrating extraction and sample cleanup in the quantification of benzodiazepines in urine by liquid chromatography tandem mass spectrometry (LC-MS/MS). The SUPRAS-RAM was synthesized in situ in the urine by the addition of 1- hexanol (154 µL) and THF (600 µL). Benzodiazepines extraction was driven by both hydrogen bonds and dispersion interactions. Removal of proteins and polar macromolecules was performed by the action of the SUPRAS through chemical and physical mechanisms. Phospholipids were removed by precipitation during SUPRAS extract evaporation. A multivariate method was used for the optimization of the extraction process by applying Box-Behnken response surface design. The proposed method was validated according to the guiding principles of the European Commission Decision (2002/657/EC). Method detection and quantification limits for the target benzodiazepines were in the intervals 0.21-0.85 ng/mL and 0.67-2.79 ng/mL, respectively. The repeatability and reproducibility (expressed as relative standard deviations) were in the range 2-6 % and 3-8%, respectively. The method enabled the simultaneous extraction of benzodiazepines (recoveries in the range 84-105%) and the removal of matrix effects. The method was applied to the analysis of 13 urine samples using external calibration. Five out of 13 samples tested positive in alprazolam and lorazepam at concentrations in the range 5.4-74 ng/mL. The method allows simple and quick sample treatment with minimal solvent consumption while delivering accurate and precise data.

Rapid and simple multi-analyte LC-MS/MS method for the determination of benzodiazepines and Z-hypnotic drugs in blood samples: Development, validation and application based on three years of toxicological analyses

Benzodiazepines (BZDs) and Z-drugs have been particularly important treatments for sleeping and anxiety disorders for many years. However, recently, a number of new benzodiazepines (named designer benzodiazepines, DBZDs) were synthesised, but some of them have never been used in the clinic; they reached the black drug market as new psychoactive substances and are used for recreational purposes. The abuse of these substances has led to many crimes and even deaths. Therefore, it is necessary to develop new methods for their quantification for forensic and clinical toxicology. A liquid chromatography-tandem mass spectrometry-based method was developed for the simultaneous determination of 20 classical BZDS, 4 DBZDs and 3 Z-hypnotic drugs in human whole blood. As a sample preparation step, liquid-liquid extraction requiring the use of only 0.5 mL of blood sample and 1 mL of extraction solvent was applied. The selectivity, linearity, carry-over effects, limits of detection (LOD) and quantification (LOQ), precision, accuracy (both intra- and inter-day assays) and recovery were evaluated for validation. Calibration curves were linear with r values > 0.98. The LODs ranged from 0.01 to 0.33, and the LOQs were assumed to be 1 ng/mL. Inter-day precisions and accuracies were in the ranges of 87.8% - 108.5% and 1.8% - 11.2%, respectively. The recovery values ranged from 81.0% to 106.7%. The developed method proved to be sensitive, specific, simple, and fast and can be quickly modified and expanded for new compounds by the optimization of MRM. The method was applied for analysis of blood samples in 145 toxicological cases over a three-year study (2017 - 2019), which allowed us to obtain information on the prevalence of the use of these substances. The most frequently determined compounds were nordazepam (87 cases; 60%), diazepam (81 cases; 55.9%), temazepam (72 cases; 49.7%), oxazepam (56 cases; 38.7%), and midazolam (36 cases; 24.8%). The ranges of concentrations were wide and are presented as box plots. The results were used for the preparation of medico-legal opinions, which proved the utility of the method for routine toxicology analyses.

Accurate quantification of EVT201 and its two metabolites in human urine using UHPLC-MS/MS method with solid phase extraction

A sensitive and accurate ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the determination of EVT201 and its two metabolites, Ro46-1927 and Ro18-5528, in human urine. Different sample preparation methods were compared, and solid-phase extraction (SPE) was finally employed. Separation conditions and mass spectrometry parameters were optimized to achieve complete separation and enough sensitivity. Finally, the three analytes were separated on an Acquity BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with a gradient mobile phase. The gradient elution consisted of acetonitrile (containing 0.1% formic acid) and 10 mM ammonium formate (containing 1% acetonitrile and 0.1% formic acid) at a flow rate of 0.50 mL/min. Detection was performed on an electrospray ionization (ESI) source in positive mode with multiple reaction monitoring (MRM). The method was fully validated in accordance with the bioanalysis guidance in Chinese Pharmacopoeia. It showed satisfying linearity, accuracy, and precision in the range of 0.2–200 ng/mL for all the three analytes. The mean extraction recoveries were 85.2%, 65.6%, 87.9%, and 86.4% for EVT201, Ro46-1927, Ro18-5528, and the IS, respectively. The method was successfully applied to the bioanalysis of 833 urine samples to determine the concentration of EVT201 and its two metabolites simultaneously.

Recent Trends in Fast Liquid Chromatography for Pharmaceutical Analysis

Background:

Liquid chromatography is the workhorse of analytical laboratories of pharmaceutical companies for analysis of bulk drug materials, intermediates, drug products, impurities and degradation products. This efficient technique is impeded by its long and tedious analysis procedures. Continuous efforts of scientists to reduce the analysis time resulted in the development of three different approaches namely, HTLC, chromatography using monolithic columns and UHPLC.

Methods:

Modern column technology and advances in chromatographic stationary phase including silica-based monolithic columns and reduction in particle and column size (UHPLC) have not only revolutionized the separation power of chromatographic analysis but also have remarkably reduced the analysis time. Automated ultra high-performance chromatographic systems equipped with state-ofthe- art software and detection systems have now spawned a new field of analysis, termed as Fast Liquid Chromatography (FLC). The chromatographic approaches that can be included in FLC are hightemperature liquid chromatography, chromatography using monolithic column, and ultrahigh performance liquid chromatography.

Results:

This review summarizes the progress of FLC in pharmaceutical analysis during the period from year 2008 to 2017 focusing on detecting pharmaceutical drugs in various matrices, characterizing active compounds of natural products, and drug metabolites. High temperature, change in the mobile phase, use of monolithic columns, new non-porous, semi-porous and fully porous reduced particle size of/less than 3μm packed columns technology with high-pressure pumps have been extensively studied and successively applied to real samples. These factors revolutionized the fast high-performance separations.

Conclusion:

Taking into account the recent development in fast liquid chromatography approaches, future trends can be clearly predicated. UHPLC must be the most popular approach followed by the use of monolithic columns. Use of high temperatures during analysis is not a feasible approach especially for pharmaceutical analysis due to thermosensitive nature of analytes.

Analysis of Benzodiazepines for Drug-Facilitated Assaults and Abuse Settings (Urine)

An overview of the detection of benzodiazepines and their respective metabolites and target analytes in urine by LC-MS/MS is described. This overview shows substantial differences in the approach to detection using this technique including optional use of β-glucuronidase to hydrolyze conjugates present in urine. There are also significant variations in the extraction method employed from the use of direct injection, liquid-liquid extraction to solid-phase extraction options, with little apparent difference in limits of detection. Chromatography was largely based on the use of C18-bonded columns; however both C8- and phenyl-bonded columns were used to affect separation. Modern-day tandem mass spectrometers are capable of exceptional sensitivity enabling detection of sub-nanogram per milliliter amounts in urine, which provide for longer detection times in the urine of suspected drug-facilitated assaults. A method employed in the laboratory of the authors is provided by way of an example for readers wishing to establish a method in their own laboratory.

A molecularly imprinted polymer based chemiluminescence array sensor for one-step determination of phenothiazines and benzodiazepines in pig urine

The residues of phenothiazines and benzodiazepines in foods of animal origin are dangerous to consumers. For inspection of their abuses, this study for the first time reported on the use of a chemiluminescence array sensor for the simultaneous determination of four phenothiazines and five benzodiazepines in pig urine. Two molecularly imprinted polymers were coated in different wells of a conventional 96-well microtiter plate as the recognition reagents. After sample loading, the absorbed analytes were initiated directly by using an imidazole enhanced bis(2,4,6-trichlorophenyl)oxalate-hydrogen peroxide system to emit light. The assay process consisted of only one sample-loading step prior to data acquisition, so one test was finished within 10 min. The limits of detection for the nine drugs in the pig urine were in a range of 0.1 to 0.6 pg/mL, and the recoveries from the fortified blank urine samples were in a range of 80.3 to 95%. Furthermore, the sensor could be reused six times. Therefore, this sensor could be used as a simple, rapid, sensitive and reusable tool for routine screening for residues of phenothiazines and benzodiazepines in pig urine.

Superparamagnetic Fe3 O4 @SiO2 core-shell composite nanoparticles for the mixed hemimicelle solid-phase extraction of benzodiazepines from hair and wastewater samples before high-performance liquid chromatography analysis

Magnetic Fe3 O4 /SiO2 composite core-shell nanoparticles were synthesized, characterized, and applied for the surfactant-assisted solid-phase extraction of five benzodiazepines diazepam, oxazepam, clonazepam, alprazolam, and midazolam, from human hair and wastewater samples before high-performance liquid chromatography with diode array detection. The nanocomposite was synthesized in two steps. First, Fe3 O4 nanoparticles were prepared by the chemical co-precipitation method of Fe(III) and Fe(II) as reaction substrates and NH3 /H2 O as precipitant. Second, the surface of Fe3 O4 nanoparticles was modified with shell silica by Stober method using tetraethylorthosilicate. The Fe3 O4 /SiO2 composite were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. To enhance their adsorptive tendency toward benzodiazepines, cetyltrimethylammonium bromide was added, which was adsorbed on the surface of the Fe3 O4 /SiO2 nanoparticles and formed mixed hemimicelles. The main parameters affecting the efficiency of the method were thoroughly investigated. Under optimum conditions, the calibration curves were linear in the range of 0.10-15 μgmL(-1) . The relative standard deviations ranged from 2.73 to 7.07%. The correlation coefficients varied from 0.9930 to 0.9996.

Metabonomic Study of Biochemical Changes in Human Hair of Heroin Abusers by Liquid Chromatography Coupled with Ion Trap-Time of Flight Mass Spectrometry

Hair analysis is with the advantage of non-invasive collection and long surveillance window. The present study employed a sensitive and reliable liquid chromatography coupled with ion trap-time of flight mass spectrometry method to study the metabonomic characters in the hair of 58 heroin abusers and 72 non-heroin abusers. Results indicated that certain endogenous metabolites, such as sorbitol and cortisol, were accelerated, and the level of arachidonic acid, glutathione, linoleic acid, and myristic acid was decreased in hair of heroin abusers. The metabonomic study is helpful for further understanding of heroin addiction and clinical diagnosis.

Photodiode array to charged aerosol detector response ratio enables comprehensive quantitative monitoring of basic drugs in blood by ultra-high performance liquid chromatography

Quantitative screening for a broad range of drugs in blood is regularly required to assess drug abuse and poisoning within analytical toxicology. Mass spectrometry-based procedures suffer from the large amount of work required to maintain quantitative calibration in extensive multi-compound methods. In this study, a quantitative drug screening method for blood samples was developed based on ultra-high performance liquid chromatography with two consecutive detectors: a photodiode array detector and a corona charged aerosol detector (UHPLC-DAD-CAD). The 2.1 mm × 150 mm UHPLC column contained a high-strength silica C18 bonded phase material with a particle size of 1.8 μm, and the mobile phase consisted of methanol/0.1% trifluoroacetic acid in gradient mode. Identification was based on retention time, UV spectrum and the response ratio from the two detectors. Using historic calibration over a one-month period, the median precision (RSD) of retention times was 0.04% and the median accuracy (bias) of quantification 6.75%. The median precision of the detector response ratio over two orders of magnitude was 12%. The applicable linear ranges were generally 0.05-5 mg L(-1). The method was validated for 161 compounds, including antipsychotics, antidepressants, antihistamines, opioid analgesics, and adrenergic beta blocking drugs, among others. The main novelty of the method was the proven utility of the response ratio of DAD to CAD, which provided the additional identification efficiency required. Unlike with mass spectrometry, the high stability of identification and quantification allowed the use of facile historic calibration.

Development of a simultaneous analytical method for selected anorectics, methamphetamine, MDMA, and their metabolites in hair using LC-MS/MS to prove anorectics abuse

Owing to the tight control of methamphetamine, it is presumed that phentermine, an amphetamine-type anorectic, has recently been considered a supplement for methamphetamine abusers in Korea. In addition, the abuse of other anorectics obtained by inappropriate means has become a social issue. Hair is a useful specimen to prove chronic drug use. Therefore, an analytical method for the simultaneous detection of phentermine, phendimetrazine, amfepramone, fenfluramine, mazindol, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA), as well as their metabolites, which covers the major amphetamines and anorectic agents in Korea, in hair was established and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The drugs and their metabolites in hair were extracted using 1 % HCl in methanol and then filtered and analyzed by LC-MS/MS with electrospray ionization in positive mode. The validation results for selectivity, linearity, matrix effect, recovery, process efficiency, intra- and interassay precision and accuracy, and processed sample stability were satisfactory. The limits of detection ranged from 0.025 to 1 ng/10 mg hair and the limits of quantification were 0.25 ng/10 mg hair for every analyte except mazindol and phentermine, for which they were 10 ng/10 mg hair. The method was successfully applied for the segmental determination of selected anorectics, methamphetamine, MDMA, and their metabolites in hair from 39 drug suspects. Among the anorectics, phentermine and/or phendimetrazine were identified with or without methamphetamine in the hair samples. Closer supervision of the inappropriate use of anorectics is necessary. Also, hair analysis is useful for monitoring the abuse potential of unnoticed drugs.

Integrated quantitative and qualitative workflow for in vivo bioanalytical support in drug discovery using hybrid Q-TOF-MS

Background: UHPLC coupled with orthogonal acceleration hybrid quadrupole-TOF (Q-TOF)-MS is an emerging technique offering new strategies for the efficient screening of new chemical entities and related molecules at the early discovery stage within the pharmaceutical industry. In the first part of this article, we examine the main instrumental parameters that are critical for the integration of UHPLC–Q-TOF technology to existing bioanalytical workflows, in order to provide simultaneous quantitative and qualitative bioanalysis of samples generated following in vivo studies. Material & Methods: Three modern Q-TOF mass spectrometers, including Bruker maXis™, Agilent 6540 and Sciex TripleTOF™ 5600, all interfaced with UHPLC systems, are evaluated in the second part of the article. The scope of this work is to demonstrate the potential of Q-TOF for the analysis of typical small molecules, therapeutic peptides (molecular weight <6000 Da), and enzymatically (i.e., trypsin, chymotrypsin and pepsin) cleaved peptides from larger proteins. Results & Discussion: This work focuses mainly on full-scan TOF data obtained under ESI conditions, the major mode of TOF operation in discovery bioanalytical research, where the compounds are selected based on their pharmacokinetic/pharmacodynamic behaviors using animal models prior to selecting a few desirable candidates for further development. Finally, important emerging TOF technologies that could potentially benefit bioanalytical research in the semi-quantification of metabolites without synthesized standards are discussed. Particularly, the utility of captive spray ionization coupled with TripleTOF 5600 was evaluated for improving sensitivity and providing normalized MS response for drugs and their metabolites. The workflow proposed compromises neither the efficiency, nor the quality of pharmacokinetic data in support of early drug discovery programs.

Methods for the analysis of nonbenzodiazepine hypnotic drugs in biological matrices

Zopiclone, zolpidem and zaleplon (Z-drugs) are nonbenzodiazepine hypnotic drugs that are used for the treatment of insomnia. These drugs were developed with the intent to overcome some disadvantages of benzodiazepines, such as dependence and next day sedation. In general, the nonbenzodiazepine hypnotic drugs are administered in oral doses daily and are widely biotransformed in the body. A large number of analytical methods based on chromatographic and electrophoretic techniques for the quantification of Z-drugs and their metabolites in biological matrices have been reported. In this review, the bioanalytical methods for Z-drugs were reviewed with the focus placed on sample preparation procedures and the separation techniques used. Furthermore, as these drugs are also reported as drugs of abuse or in drug-facilitated crime, screening methods that simultaneously cover these drugs and also other drugs of abuse were included in this review.