A validated method for simultaneous determination of codeine, codeine-6-glucuronide, norcodeine, morphine, morphine-3-glucuronide and morphine-6-glucuronide in post-mortem blood, vitreous fluid, muscle, fat and brain tissue by LC-MS

Suitability of cardiac blood, brain tissue, and muscle tissue as alternative matrices for toxicological evaluation in postmortem cases

Drug concentrations in peripheral blood are often used to evaluate whether death was caused by drug intoxication. In some cases, peripheral blood is not available, and analytical results of alternative matrices should instead be used in the toxicological evaluation. However, reference concentrations of alternative matrices are few, which makes interpretation of results a challenge. In this study, concentrations of selected benzodiazepines, opioids, illicit drugs, and other commonly used drugs in postmortem femoral blood, cardiac blood, brain tissue, and muscle tissue are presented. Alternative matrix-to-femoral blood drug concentration ratios and correlations of blood and alternative matrix drug concentrations were calculated to examine which of the investigated alternative matrices were most suited to use for toxicological evaluation in cases where peripheral blood is not available. The results showed that concentrations in cardiac blood, brain tissue, and muscle tissue could be useful in the postmortem evaluation of most of the 19 selected analytes. In most cases, analytes were detected in all the alternative matrices. The median concentration ratios for the selected analytes in brain tissue, cardiac blood, and muscle tissue relative to femoral blood ranged from 0.57 to 3.42, 0.59 to 1.87, and 0.67 to 7.04, respectively. Overall, cardiac blood provided the concentrations most comparable with femoral blood concentrations, indicating that cardiac blood can be useful in cases where femoral blood is not available. However, the measured concentrations should be interpreted with caution.

A UHPLC-MS-MS Method for the Determination of 84 Drugs of Abuse and Pharmaceuticals in Blood

The analysis of blood samples for forensic or clinical intoxication cases is a daily routine in an analytical laboratory. The list of 'suspect' drugs of abuse and pharmaceuticals that should be ideally screened is large, so multi-targeted methods for comprehensive detection and quantification are a useful tool in the hands of a toxicologist. In this study, the development of an ultra-high performance liquid chromatography (LC)-tandem mass spectrometry (MS-MS) method is described for the detection and quantification of 84 drugs and pharmaceuticals in postmortem blood. The target compounds comprise pharmaceutical drugs (antipsychotics, antidepressants, etc.), some of the most important groups of drugs of abuse: opiates, cocaine, cannabinoids, amphetamines, benzodiazepines and new psychoactive substances. Sample pretreatment was studied applying a modified Mini-QuEChERS single step, and the best results were obtained after adding a mixture of 20 mg MgSO4, 5 mg K2CO3 and 5 mg NaCl together with 600 μL of cold acetonitrile in 200 μL of sample. After centrifugation, the supernatant was collected for direct injection. LC-MS analysis took place on a C18 column with a gradient elution over 17 min. The method was found to be selective and sensitive, offering limits of detection ranging from 0.01 to 9.07 ng/mL. Validation included evaluation of limit of quantification, recovery, carryover, matrix effect, accuracy and precision of the method. The method performed satisfactorily in relation to established bioanalytical criteria and was therefore applied to the analysis of blood obtained postmortem from chronic drug abusers, offering unambiguous identification and quantitative determination of drugs in postmortem blood.

Determination of the alcohol biomarker phosphatidylethanol 16:0/18:1 and 33 compounds from eight different drug classes in whole blood by LC-MS/MS

INTRODUCTION

Most bioanalytical LC-MS/MS methods are developed for determination of single drugs or classes of drugs, but a multi-compound LC-MS/MS method that can replace several methods could reduce both analysis time and costs. The aim of this study was to develop a high-throughput LC-MS/MS method for determination of the alcohol biomarker phosphatidylethanol 16:0/18:1 (PEth 16:0/18:1) and 33 other compounds from eight different drug classes in whole blood.

METHODS

Whole-blood samples were prepared by 96-well supported liquid extraction (SLE). Chromatographic separations were performed on a biphenyl core shell column with a mobile phase consisting of 10 mM ammonium formate, pH 3.1 and methanol. Each extract was analyzed twice by LC-MS/MS, injecting 0.4 μL and 2 μL, in order to obtain narrow and symmetrical peaks and good sensitivity for all compounds. Stable isotope-labeled internal standards were used for 31 of the 34 compounds.

RESULTS

A 96-well SLE reversed phase LC-MS/MS method for determination of PEth 16:0/18:1 and 33 other compounds from eight different drug classes was developed and validated. By using an organic solvent mixture of isopropanol/ methyl tert-butyl ether (1:5, v:v), all compounds, including the polar and ampholytic compounds pregabalin, gabapentin and benzoylecgonine, was extracted by 96-well SLE.

DISCUSSION/CONCLUSION

For the first time an LC-MS/MS method for the determination of alcohol biomarker PEth 16:0/18:1 and drugs and metabolites from several different drug classes was developed and validated. The developed LC-MS/MS method can be used for high-throughput analyses and sensitive determinations of the 34 compounds in whole blood.

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).

Determination of 12 commonly found compounds in DUID cases in whole blood using fully automated supported liquid extraction and UHPLC-MS/MS

A high-throughput UHPLC-MS/MS method for the most frequently found compounds; tetrahydrocannabinol (THC), amphetamine, methamphetamine, MDMA, clonazepam, diazepam, nordiazepam, oxazepam, alprazolam, nitrazepam, morphine, and codeine, in driving under the influence of drugs (DUID) cases in whole blood, is presented. Automated sample preparation by 96-well supported liquid extraction (SLE) plates with ethyl acetate + heptane (80 + 20, v/v) as organic solvent was carried out on a Freedom Evo 200 platform from Tecan. An aliquot of 100 μL whole blood was used. Sample preparation time for 96 samples was 1.5 h. Compounds were separated with gradient elution on a C₁₈ column (50 × 2.1 mm, 1.7 μm) with a mobile phase consisting of 5 mM pH 10.2 ammonium formate and methanol. The run time was 4.5 min and 1 μL was injected on an Acquity UPLC I-Class system with a Xevo TQS tandem-quadrupole mass spectrometer in multiple-reaction monitoring mode (MRM) from Waters. Isotope labelled, ¹³C, internal standards (ISs) were used for all compounds except for alprazolam and morphine, which had deuterated analogs. Quantification was carried out with calibrators without whole blood matrix. Full validation was carried out according to international guidelines, and a new approach for evaluation of process efficiency (PE) has been presented. Linear or quadratic weighted (1/x) calibration curves were used with R² ≥ 0.999. The method showed satisfactory deviations ±16% when compared to the existing methods, and satisfactory agreement with proficiency testing control samples (z-score -1.6 to 1.8, n = 16 samples). The precision, estimated as the relative standard deviation (RSD) of the concentration difference between results from two independent analyses of authentic whole blood samples, was ≤7.2% in antemortem and ≤9.3% in postmortem samples. Recovery was ≥85% for all the compounds, except morphine ≥62% and THC ≥ 50%. PE was satisfactory for all the compounds with low variation in IS response, RSD ≤ 16% (THC 27%) in antemortem samples and ≤34% (THC 66%) in postmortem samples. To the best of our knowledge, this is the first automated 96-well SLE UHPLC-MS/MS method developed for the simultaneous determination of these 12 compounds in whole blood covering the concentration ranges found in forensic samples. The method has been used in routine work during the last ten months, analysing about 9900 antemortem and 1000 postmortem whole blood samples, and has proven to be robust and reliable.

Endogenous Opiates and Behavior: 2016

This paper is the thirty-ninth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2016 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

Glucuronidation: driving factors and their impact on glucuronide disposition

Glucuronidation is a well-recognized phase II metabolic pathway for a variety of chemicals including drugs and endogenous substances. Although it is usually the secondary metabolic pathway for a compound preceded by phase I hydroxylation, glucuronidation alone could serve as the dominant metabolic pathway for many compounds, including some with high aqueous solubility. Glucuronidation involves the metabolism of parent compound by UDP-glucuronosyltransferases (UGTs) into hydrophilic and negatively charged glucuronides that cannot exit the cell without the aid of efflux transporters. Therefore, elimination of parent compound via glucuronidation in a metabolic active cell is controlled by two driving forces: the formation of glucuronides by UGT enzymes and the (polarized) excretion of these glucuronides by efflux transporters located on the cell surfaces in various drug disposition organs. Contrary to the common assumption that the glucuronides reaching the systemic circulation were destined for urinary excretion, recent evidences suggest that hepatocytes are capable of highly efficient biliary clearance of the gut-generated glucuronides. Furthermore, the biliary- and enteric-eliminated glucuronides participate into recycling schemes involving intestinal microbes, which often prolong their local and systemic exposure, albeit at low systemic concentrations. Taken together, these recent research advances indicate that although UGT determines the rate and extent of glucuronide generation, the efflux and uptake transporters determine the distribution of these glucuronides into blood and then to various organs for elimination. Recycling schemes impact the apparent plasma half-life of parent compounds and their glucuronides that reach intestinal lumen, in addition to prolonging their gut and colon exposure.

Vitreous humor analysis for the detection of xenobiotics in forensic toxicology: a review

Vitreous humor (VH) is a gelatinous substance contained in the posterior chamber of the eye, playing a mechanical role in the eyeball. It has been the subject of numerous studies in various forensic applications, primarily for the assessment of postmortem interval and for postmortem chemical analysis. Since most of the xenobiotics present in the bloodstream are detected in VH after crossing the selective blood-retinal barrier, VH is an alternative matrix useful for forensic toxicology. VH analysis offers particular advantages over other biological matrices: it is less prone to postmortem redistribution, is easy to collect, has relatively few interfering compounds for the analytical process, and shows sample stability over time after death. The present study is an overview of VH physiology, drug transport and elimination. Collection, storage, analytical techniques and interpretation of results from qualitative and quantitative points of view are dealt with. The distribution of xenobiotics in VH samples is thus discussed and illustrated by a table reporting the concentrations of 106 drugs from more than 300 case reports. For this purpose, a survey was conducted of publications found in the MEDLINE database from 1969 through April 30, 2015.