Dilute and shoot approach for toxicology testing

Toxicology testing is performed in clinical settings, forensic settings, and for controlling doping. Drug screening is a toxicology test to determine if drugs are present in biological samples. The most common specimen type for drug testing is urine, as drugs and/or their metabolites are often more concentrated in the urine, extending the detection window of drugs. The dilute-and-shoot method is a simple procedure used in toxicology testing, where a sample is diluted before being directly injected into the liquid chromatography-mass spectrometry (LC-MS) system. This method is easy, quick, and cost-saving, and can be used for protein-poor liquid specimens such as urine. Thus, it is reasonable and attractive for busy toxicology laboratories to combine the dilute-and-shoot method with high-resolution hyphenated-MS for urine drug screening. This method has several disadvantages, including a suboptimal detection capability for certain analytes, as well as interference from co-eluting matrix components called matrix effects, in which co-eluting matrix molecules alter the ionization efficiency of the analyte molecules at the ionization source in LC-MS, altering (mostly reducing) the analyte detection capability. The matrix effect testing is essential for the validation of LC-MS-based assays. A reasonable approach to addressing these undesirable effects would be to minimize these components. The most straightforward approach is to reduce the amounts of matrix components by using a higher dilution of the specimen and a lower volume for specimen injection. Optimization of the chromatographic separation is another reasonable approach for reducing co-eluting matrix components with the analyte.

Diverse Drug Classes Partition into Human Sweat: Implications for Both Sweat Fundamentals and for Therapeutic Drug Monitoring

ABSTRACT

Therapeutic drug monitoring to optimize drug therapy typically relies on the inconvenience of repeated plasma sampling. Sweat is a potential alternative biofluid convenient for sampling. However, limited information exists regarding the range of drugs excreted in sweat and their correlation with plasma concentrations. This study evaluated drugs in sweat and plasma of an ambulatory clinical cohort. Pilocarpine-induced sweat was collected from ambulatory participants at a single instance using an absorbent nylon mesh, followed by concurrent blood sampling for ratio and correlation analyses. In a model drug study, the pharmacokinetics of acetaminophen in sweat and plasma were compared. Of the 14 drugs and 2 metabolites monitored in the clinical study, all compounds were present in sweat and plasma; however, the sweat-to-plasma ratio varied substantially across the drugs. Opioids and methocarbamol demonstrated the highest concentrations in sweat, sometimes exceeding plasma concentrations. Selected antidepressants and muscle relaxants were also detected in sweat at a 2-10-fold dilution to the plasma. Others, such as gabapentin and pregabalin, were highly diluted (>30-fold) in sweat compared with plasma. Together, these data suggest that molecular attributes, specifically hydrophobicity (logP) and charge state at physiologic pH (7.4), enable reasonable prediction of sweat-to-plasma drug correlation. These findings demonstrated that sweat could be used as an alternative biofluid for therapeutic drug monitoring. The findings also suggest that although it has been broadly accepted that small hydrophobic molecules most likely have a strong plasma correlation, there is a small window of hydrophobicity and charge state that permits sweat partitioning.

Conductive vial electromembrane extraction of opioids from oral fluid

The use of oral fluid as sample matrix has gained significance in the analysis of drugs of abuse due to its non-invasive nature. In this study, the 13 opioids morphine, oxycodone, codeine, O-desmethyl tramadol, ethylmorphine, tramadol, pethidine, ketobemidone, buprenorphine, fentanyl, cyclopropylfentanyl, etonitazepyne, and methadone were extracted from oral fluid using electromembrane extraction based on conductive vials prior to analysis with ultra-high performance liquid chromatography-tandem mass spectrometry. Oral fluid was collected using Quantisal collection kits. By applying voltage, target analytes were extracted from oral fluid samples diluted with 0.1% formic acid, across a liquid membrane and into a 300 μL 0.1% (v/v) formic acid solution. The liquid membrane comprised 8 μL membrane solvent immobilized in the pores of a flat porous polypropylene membrane. The membrane solvent was a mixture of 6-methylcoumarin, thymol, and 2-nitrophenyloctyl ether. The composition of the membrane solvent was found to be the most important parameter to achieve simultaneous extraction of all target opioids, which had predicted log P values in the range from 0.7 to 5.0. The method was validated in accordance to the guidelines by the European Medical Agency with satisfactory results. Intra- and inter-day precision and bias were within guideline limits of ± 15% for 12 of 13 compounds. Extraction recoveries ranged from 39 to 104% (CV ≤ 23%). Internal standard normalized matrix effects were in the range from 88 to 103% (CV ≤ 5%). Quantitative results of authentic oral fluid samples were in accordance with a routine screening method, and external quality control samples for both hydrophilic and lipophilic compounds were within acceptable limits.

Determination of Patient Adherence for Duloxetine in Urine

Duloxetine, known by its brand name, CymbaltaTM, is a selective serotonin and norepinephrine reuptake inhibitor used to treat major depressive disorders. Determination of patient compliance for duloxetine is typically determined through medication possession ratio (MPR) or plasma concentrations. The purpose of this paper was to characterize normal urinary duloxetine concentrations in patients prescribed duloxetine to monitor patient adherence. Patient data collected from routine screens for duloxetine concentrations in urine were included in this study. Inclusion criteria consisted of patients who were prescribed duloxetine and (i) tested positive for duloxetine, (ii) tested negative for illicit substances and (iii) included creatinine, age and duloxetine dose administered. Of the 5,592 patient urines screened, 2,004 of the results fit into the inclusion criteria. Positive urine concentrations of duloxetine ranged from 50 to 2,722 ng/mL. Duloxetine urine concentrations were normalized to creatinine and dose further characterized by sex, age, body mass index (BMI) and dose in milligrams. Sample distribution included urines collected from 1,487 females and 517 males. The age range of the specimen donors was between 15 and 90 years old with an average age of 52. BMI levels ranged from 13.9 (underweight) to 88.1 (obese), with the average BMI being 33.5. The most common dose of duloxetine prescribed was a daily, oral dose of 60 mg. Analysis of the normalized, transformed creatinine concentrations showed that there was a significant statistical difference (P < 0.05) in the urinary duloxetine concentrations by sex and by dose (mg). Female patients further showed a statistical difference in urinary duloxetine concentration in age groups 18-64 and 64 and older. By characterizing urinary duloxetine concentrations in patients prescribed the medication, normalized distributions of data ranges have been established. These data ranges for urinary duloxetine concentrations can be used to determine patient compliance with duloxetine in routine, clinical samples.

Stability of drugs of abuse in synthetic oral fluid investigated using a simple "dilute and inject" method of analysis

Human oral fluid is well established as a matrix for drug screening, particularly in the workplace. The need to synthesise synthetic oral fluid (SOF) has been recognised in order to overcome human oral fluid's composition variability. We have used SOF spiked with six common drugs of abuse or their primary metabolites: morphine, amfetamine, benzoylecgonine, cocaine, diazepam, and (−)‐Δ⁹‐tetrahydrocannabinol (THC) in order to assess the suitability of this matrix for quality assurance purposes. For confirmation of a drug screening test, controls and spiked standards are normally required. All our analytes were detected by LC–MS/MS using a quick and easy “dilute and inject” sample preparation approach as opposed to relatively slower solid‐phase extraction. The limit of detection (LOD) was 10 ng/ml for diazepam and THC and 5 ng/ml for morphine, amfetamine, benzoylecgonine and cocaine. Validation results showed good accuracy as well as inter‐ and intra‐assay precision (CV [%] < 5). Our work highlighted the importance of adding Tween® 20 to the SOF and calibrants to reduce losses when handling THC. Furthermore, drug stability was tested at various temperatures (5°C, 20°C and 40°C), for a number of days or after freeze–thaw cycles. Recommendations regarding storage are provided, the spiked SOF being stable at 5°C for up to 1 week without significant drug concentration loss.

Bioanalytical strategies in drug discovery and development

A reliable, rapid, and effective bioanalytical method is essential for the determination of the pharmacokinetic, pharmacodynamic, and toxicokinetic parameters that inform the safety and efficacy profile of investigational drugs. The overall goal of bioanalytical method development is to elucidate the procedure and operating conditions under which a method can sufficiently extract, qualify, and/or quantify the analyte(s) of interest and/or their metabolites for the intended purpose. Given the difference in the physicochemical properties of small and large molecule drugs, different strategies need to be adopted for the development of an effective and efficient bioanalytical method. Herein, we provide an overview of different sample preparation strategies, analytical platforms, as well as procedures for achieving high throughput for bioanalysis of small and large molecule drugs.

Development and validation of quantitative analytical method for 50 drugs of antidepressants, benzodiazepines and opioids in oral fluid samples by liquid chromatography–tandem mass spectrometry

Purpose

We developed and validated a method for quantitative analysis of 50 psychoactive substances and metabolites (antidepressants, benzodiazepines and opioids) in oral fluid samples using simple liquid–liquid extraction procedure followed by liquid chromatography–tandem mass spectrometry (LC–MS/MS).

Method

Oral fluid samples were collected using Quantisal™ device and extracted by liquid–liquid extraction with 1.0 mL of methyl tert-butyl ether and then analyzed using LC–MS/MS.

Results

The method attended method validation criteria, with limits of quantification as low as 0.5 and 1.0 ng/mL, and linearity between 0.5–50.0 ng/mL for antidepressants, 0.5–25.0 ng/mL for benzodiazepines and 1.0–50.0 ng/mL to opioids. During method validation, bias and imprecision values were not greater than 16 and 20%, respectively. Ionization suppression/enhancement bias results were not greater than 25%. No evidence of carryover was observed. Sample stability studies showed that almost all analytes were stable at 25 °C for 3 days and at 4 °C for 7 days. Freeze–thaw cycles stability showed that most antidepressants and opioids were stable under these conditions. Autosampler stability study showed that all analytes were stable for 24 h, except for nitrazepam and 7-aminoclonazepam. Thirty-eight authentic oral fluid samples were analyzed; 36.8% of the samples were positive for 2 drugs. Citalopram was the most common drug found, followed by venlafaxine.

Conclusions

The method was validated according to international recommendations for the 50 analytes, showing low limits of quantification, good imprecision and bias values, using simple liquid–liquid extraction, and was successfully applied to authentic oral fluid samples analysis.

Validation of two methods for the quantitative analysis of cocaine and opioids in biological matrices using LCMSMS

The proliferation of misuse of prescription and non-prescription opioids, in recent years, has caused an opioid epidemic in the United States. Forensic toxicology laboratories often encounter implications of abuse in both driving under the influence of drugs and death investigation cases. The Virginia Department of Forensic Science has seen over a 190% increase in the number of reported opioids in death investigation cases over the past several years. Traditionally, analyses are completed by individual drug class, which subsequently requires an individual case to be evaluated using multiple analytical techniques for comprehensive analysis. To ease the impact of increasing case submissions and case complexity, two liquid chromatography-tandem mass spectrometry (LCMSMS) methods for the quantitative analysis of opioids, cocaine, and cocaine metabolites in biological matrices have undergone a fit-for-purpose validation. The methods were compared to determine the advantages and disadvantages of each analytical technique. Two sample preparation techniques, protein precipitation and solid-phase extraction, were employed for quantitative validation. Validation aspects evaluated included accuracy and precision, sensitivity, linearity, matrix effects, recovery, carryover, interferences, dilution integrity, and post-extraction stability. The accuracy of the protein precipitation method ranged from 80 ± 3% to 101 ± 10%. The accuracy of the solid-phase extraction method ranged from 88 ± 9% to 119 ± 3%. Additionally, within-run and intermediate precision was within ±20% for both extraction techniques. Although ionization suppression was noted, it was determined to have minimal effect on the methods. The newly developed methods require less sample volume and combine four analytical techniques into one method, which significantly impacts laboratory productivity.

A Rapid LC-MS-MS Method for the Quantitation of Antiepileptic Drugs in Urine

Epilepsy is a common neurologic disease that requires treatment with one or more medications. Due to the polypharmaceutical treatments, potential side effects, and drug-drug interactions associated with these medications, therapeutic drug monitoring is important. Therapeutic drug monitoring is typically performed in blood due to established clinical ranges. While blood provides the benefit of determining clinical ranges, urine requires a less invasive collection method, which is attractive for medication monitoring. As urine does not typically have established clinical ranges, it has not become a preferred specimen for monitoring medication adherence. Thus, large urine clinical data sets are rarely published, making method development that addresses reasonable concentration ranges difficult. An initial method developed and validated in-house utilized a universal analytical range of 50-5,000 ng/mL for all antiepileptic drugs and metabolites of interest in this work, namely carbamazepine, carbamazepine-10,11-epoxide, eslicarbazepine, lamotrigine, levetiracetam, oxcarbazepine, phenytoin, 4-hydroxyphenytoin, and topiramate. This upper limit of the analytical range was too low leading to a repeat rate of 11.59% due to concentrations >5,000 ng/mL. Therefore, a new, fast liquid chromatography-tandem mass spectrometry (LC-MS-MS) method with a run time under 4 minutes was developed and validated for the simultaneous quantification of the previously mentioned nine antiepileptic drugs and their metabolites. Urine samples were prepared by solid-phase extraction and analyzed using a Phenomenex Phenyl-Hexyl column with an Agilent 6460 LC-MS-MS instrument system. During method development and validation, the analytical range was optimized for each drug to reduce repeat analysis due to concentrations above the linear range and for carryover. This reduced the average daily repeat rate for antiepileptic testing from 11.59% to 4.82%. After validation, this method was used to test and analyze patient specimens over the course of approximately one year. The resulting concentration data were curated to eliminate specimens that could indicate an individual was noncompliant with their therapy (i.e., positive for illicit drugs) and yielded between 20 and 1,700 concentration points from the patient specimens, depending on the analyte. The resulting raw quantitative urine data set is presented as preliminary reference ranges to assist with interpreting urine drug concentrations for the nine aforementioned antiepileptic medications and metabolites.

Determination of morphine and its metabolites in the biological samples: an updated review

Morphine (MO) as an opioid analgesic is used for the treatment of moderate-to-severe pains, particularly cancer-related pains. Pharmacologic studies on MO are complicated due to drugs binding to the protein or metabolization to active metabolites, and even inter-individual variability. This necessitates the selection of a reliable analytical method for monitoring MO and the concentrations of its metabolites in the biological samples for the pharmacokinetic or pharmacodynamic investigations. Therefore, this study was conducted to review all the analytical research carried out on MO and its metabolites in the biological samples during 2007-2019 as an update to the study by Bosch et al. (2007).

A Dilute and Shoot LC–MS/MS Method for Antipsychotics in Urine

Adherence to prescribed antipsychotics is an ongoing problem. Traditionally, estimates of adherence have been made from patient interviews, pill counting and blood testing. A number of methods for the analysis of antipsychotics in blood have been reported for both therapeutic drug monitoring and postmortem testing for toxicity. This report details a dilute and shoot method for the analysis of 19 different antipsychotics and metabolites. The method takes advantage of earlier reports demonstrating unique, prevalent urine metabolites for aripiprazole, brexpiprazole, haloperidol and lurasidone to enhance sensitivity for these analytes. With a fast analysis time and minimal sample preparation, this method can be used for quantitation of antipsychotics in urine. Finally, this method has been used to test samples for over a year with the results summarized in this report. While further improvements are certainly possible, this method is selective and sensitive for this group of important compounds.

Opioid Use in Pregnant Women and Neonatal Abstinence Syndrome-A Review of the Literature

Opiate use during pregnancy has been an increasing problem over the last two decades, making it an important social and health concern. The use of such substances may have serious negative outcomes in the newborn, and clinical and cognitive conditions have been reported, including neonatal abstinence syndrome, developmental problems, and lower cognitive performance. These conditions are common when opiates are used during pregnancy, making the prescription of these kinds of drugs problematic. Moreover, the mother may develop opiate addiction, thus, increasing the likelihood of the infant being born with any of those conditions. This paper reviews the use of opiates during pregnancy and focuses mainly on the neonatal abstinence syndrome. First, the commonly prescribed opiates will be identified, namely those usually involved in cases of addiction and/or neonatal abstinence syndrome. Second, published approaches to deal with those problems will be presented and discussed, including the treatment of both the mother and the infant. Finally, we will outline the treatments that are safest and most efficient, and will define future goals, approaches, and research directions for the scientific community regarding this problem.

Development of a Quantitative LC-MS-MS Assay for Codeine, Morphine, 6-Acetylmorphine, Hydrocodone, Hydromorphone, Oxycodone and Oxymorphone in Neat Oral Fluid

Recent advances in analytical capabilities allowing for the identification and quantification of drugs and metabolites in small volumes at low concentrations have made oral fluid a viable matrix for drug testing. Oral fluid is an attractive matrix option due to its relative ease of collection, reduced privacy concerns for observed collections and difficulty to adulterate. The work presented here details the development and validation of a liquid chromatography tandem mass spectrometry (LC-MS-MS) method for the quantification of codeine, morphine, 6-acetylmorphine, hydrocodone, hydromorphone, oxycodone and oxymorphone in neat oral fluid. The calibration range is 0.4-150 ng/mL for 6-acetylmorphine and 1.5-350 ng/mL for all other analytes. Within-run and between-run precision were <5% for all analytes except for hydrocodone, which had 6.2 %CV between runs. Matrix effects, while evident, could be controlled using matrix-matched controls and calibrators with deuterated internal standards. The assay was developed in accordance with the proposed mandatory guidelines for opioid confirmation in federally regulated workplace drug testing. The use of neat oral fluid, as opposed to a collection device, enables collection of a single sample that can be split into separate specimens.

Preconcentration of morphine and codeine using a magnetite/reduced graphene oxide/silver nano-composite and their determination by high-performance liquid chromatography

A novel magnetic solid-phase extraction technique based on a ternary nano-composite, magnetite/reduced graphene oxide/silver, as a nano-sorbent was developed for simultaneous extraction/preconcentration and measurement of morphine and codeine in biological samples by high-performance liquid chromatography. The magnetic ternary nano-composite was synthesized and its functional groups, morphological structure, and magnetic properties were characterized by field emission scanning electron microscopy, vibrating sample magnetometer, powder X-ray diffraction, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The optimizing of the significant variables affecting the extraction process was evaluated by a response surface methodology. In the optimized conditions, the constructed calibration curves for morphine and codeine are linear in the range of 0.01-10 μg L^-1 with correlation coefficients of 0.9983 and 0.9976, respectively. The detection limit and enrichment factor for morphine and codeine are 1.8 ng L^-1, 1000 and 2.1 ng L^-1, 1000, respectively. The presented technique was employed for the monitoring of morphine and codeine in numerous blood and urine samples with relative recoveries between 97.0 and 102.5%, and relative standard deviations of 1.02-5.10% for the spiked samples.

Nicotine and cotinine in oral fluid: Passive exposure vs active smoking

Scheidweiler and colleagues have clinically tested and identified a reporting cutoff (10 ng/mL) of nicotine and cotinine in oral fluid that could reliably determine active smoking in patients. The results from that study were reevaluated using a large data set of oral fluid nicotine and cotinine results available from pain medication monitoring. Additionally, test results from patients using a nicotine transdermal patch delivery device are compared with those from smokers. Finally, oral fluid test results collected over a 2-year period were normalized and transformed to yield a near Gaussian distribution for nicotine. The normalized and transformed data reveal the presence of two independent populations: a larger population consistent with active smokers and a smaller population consistent with those passively exposed to smoke. Furthermore, application of this model to patients prescribed transdermal nicotine reveals oral fluid levels consistent with those of active smokers. The clinical delineation of smokers from non-smokers reported earlier is supported by the oral fluid nicotine data modelling presented herein. These data indicate that oral fluid is an acceptable sample matrix for determining the smoking status of patients. Further, these data indicate that oral fluid test results are indistinguishable between patients prescribed transdermal patches and active smokers; however, oral fluid testing can determine absence of patches or smoking.

Zolpidem and Zolpidem Carboxylic Acid Results from Medication Monitoring

Zolpidem (Ambien®) is one of the "Z" drugs often used to improve sleep in older patients and those suffering from insomnia. Schwope, D.M., DePriest, A., Black, D.L., Caplan, Y.H., Cone, E.J., Heltsley, R. (2014) Determing zolpidem compliance: urinary metabolite detection and prevalence in chronic pain patients . Journal of Analytical Toxicology, 38, 513-518 reported that zolpidem in urine is not very prevalent being present <23% of the time in patient urine while the major metabolite, zolpidem 4-phenyl carboxylic acid (ZCA), is much more prevalent in urine with positive rates as high as 50% of the patient samples reviewed. Results from patient testing over a year's time are in agreement with the reported zolpidem results. However, the data observed herein for ZCA are not consistent with the earlier report. These data suggest that monitoring ZCA may result in even higher levels of positivity. Further, while the Food and Drug Administration has pointed out that female dosing should be half that given to males, results of this population testing indicate that the majority of patients (83% male and 73% female) receive 10 mg/day or 12.5 mg/day for Ambien CR® with females demonstrating statistically significantly higher levels of ZCA albeit zolpidem levels are not statistically significantly different between men and women. Estimates of patient positivity are dependent upon the value of the limit of quantification (LOQ) as demonstrated by the zolpidem results herein (LOQ = 50 ng/mL vs. 4 ng/mL). However, even with a much higher LOQ of 50 ng/mL for ZCA in this work, the positivity from ZCA results is significantly higher (e.g., 64.8%) than reported earlier (50.3%). Nevertheless, these data support the addition of ZCA for monitoring zolpidem in urine.

Drug exposure during pregnancy: analytical methods and toxicological findings

Drug use during pregnancy constitutes a major preventable worldwide public health issue. Birth defects, growth retardation and neurodevelopmental disorders are associated with tobacco, alcohol or drugs of abuse exposure during pregnancy. Besides these adverse health effects, drug use during pregnancy also raises legal and social concerns. Identification and quantification of drug markers in maternal and newborn biological samples offers objective evidence of exposure and complements maternal questionnaires. We reviewed the most recent analytical methods for quantifying drugs of abuse, tobacco, alcohol and psychotropic drugs in maternal, newborn and maternal-fetal unit biological samples by gas and liquid chromatography coupled to mass spectrometry. In addition, manuscripts comparing the usefulness of different biological samples to detect drug exposure during pregnancy were reviewed.

Analytical Considerations When Developing an LC-MS/MS Method for More than 30 Analytes

BACKGROUND

While validation of analytical (LC-MS/MS) methods has been documented in any number of articles and reference texts, the optimal design and subsequent validation of a method for over 30 analytes presents special challenges. Conventional approaches to calibration curves, controls, and run time are not tenable in such methods. This report details the practical aspects of designing and implementing such a method in accordance with College of American Pathologists validation criteria.

METHODS

Conventional criteria were followed in the design and validation of a method for 34 analytes and 15 internal standards by LC-MS/MS. These criteria are laid out in a standard operating procedure, which is followed without exception and is consistent with College of American Pathologists criteria.

RESULTS

The method presented herein provides quality results and accurate medication monitoring. The method was optimized to negate interferences (both from within the method and from potential concomitant compounds), increase throughput, and provide reproducible quality quantification over relevant analyte concentrations ranges.

CONCLUSIONS

The method was designed primarily with quality and accurate medication monitoring in mind. The method achieves these goals by use of novel approaches to calibration curves and controls that both improve performance and minimize risk (financial and operational). As automation and LC-MS/MS equipment continue to improve, it is expected that more methods like this one will be developed.

Urine and oral fluid drug testing in support of pain management

In recent years, the abuse of opioid drugs has resulted in greater prevalence of addiction, overdose, and deaths attributable to opioid abuse. The epidemic of opioid abuse has prompted professional and government agencies to issue practice guidelines for prescribing opioids to manage chronic pain. An important tool available to providers is the drug test for use in the initial assessment of patients for possible opioid therapy, subsequent monitoring of compliance, and documentation of suspected aberrant drug behaviors. This review discusses the issues that most affect the clinical utility of drug testing in chronic pain management with opioid therapy. It focuses on the two most commonly used specimen matrices in drug testing: urine and oral fluid. The advantages and disadvantages of urine and oral fluid in the entire testing process, from specimen collection and analytical methodologies to result interpretation are reviewed. The analytical sensitivity and specificity limitations of immunoassays used for testing are examined in detail to draw attention to how these shortcomings can affect result interpretation and influence clinical decision-making in pain management. The need for specific identification and quantitative measurement of the drugs and metabolites present to investigate suspected aberrant drug behavior or unexpected positive results is analyzed. Also presented are recent developments in optimization of test menus and testing strategies, such as the modification of the standard screen and reflexed-confirmation testing model by eliminating some of the initial immunoassay-based tests and proceeding directly to definitive testing by mass spectrometry assays.

Quetiapine Carboxylic Acid and Quetiapine Sulfoxide Prevalence in Patient Urine

Treatment adherence is often an issue with mental health patients. For those prescribed quetiapine (Seroquel^®), the low levels of parent drug and plasma metabolite(s) (e.g., 7-hydroxyquetiapine) typically used in urine drug monitoring can result in false negatives with concomitant unfavorable impacts on patient care. Literature review coupled with liquid chromatography/time-of-flight mass spectrometry analysis of patient positive urine samples indicated the presence of quetiapine carboxylic acid and quetiapine sulfoxide as significant urinary metabolites of quetiapine. Analysis of these two metabolites determined that they are abundant in the urine of quetiapine patients and can result in apparent adherence rates that are improved relative to those determined using only quetiapine and 7-hydroxyquetiapine. For example, analysis of a random set of 114 patients who were prescribed quetiapine exhibited an apparent adherence rate of 47% using the quetiapine carboxylic acid and quetiapine sulfoxide metabolites. Traditional metabolite testing with quetiapine and 7-hydroxyquetiapine yielded apparent adherence rates of ~31% while all four analytes resulted in apparent adherence of 48%. The prevalence of these metabolites suggests that quetiapine urine drug testing would be more consistent with prescriptions when they are included in the analysis.

Annual banned-substance review: analytical approaches in human sports drug testing

The aim of improving anti-doping efforts is predicated on several different pillars, including, amongst others, optimized analytical methods. These commonly result from exploiting most recent developments in analytical instrumentation as well as research data on elite athletes' physiology in general, and pharmacology, metabolism, elimination, and downstream effects of prohibited substances and methods of doping, in particular. The need for frequent and adequate adaptations of sports drug testing procedures has been incessant, largely due to the uninterrupted emergence of new chemical entities but also due to the apparent use of established or even obsolete drugs for reasons other than therapeutic means, such as assumed beneficial effects on endurance, strength, and regeneration capacities. Continuing the series of annual banned-substance reviews, literature concerning human sports drug testing published between October 2014 and September 2015 is summarized and reviewed in reference to the content of the 2015 Prohibited List as issued by the World Anti-Doping Agency (WADA), with particular emphasis on analytical approaches and their contribution to enhanced doping controls.