Determination of co-administrated opioids and benzodiazepines in urine using column-switching solid-phase extraction and liquid chromatography–tandem mass spectrometry

Review of LC techniques for determination of methadone and its metabolite in the biological samples

Methadone (MTD) is a synthetic analgesic drug used for treating opioid dependence and effectively used clinically for patients with severe pain. The abuse of MTD may lead to poisoning, disorder in the central nervous system and even death. The regular monitoring of MTD in biological matrices including serum, plasma and urine samples is an effective way to control abuse of MTD. In this manner, the selection of analytical monitoring of MTD in biological matrices is of paramount importance. This study was conducted to review high-performance liquid chromatography (HPLC) techniques carried out on MTD and its main metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in the biological samples during 2015-June 2021.

Comparison of the Detection Windows of Heroin Metabolites in Human Urine Using Online SPE and LC-MS/MS: Importance of Morphine-3-Glucuronide

Heroin abuse is a serious problem that endangers human health and affects social stability. Though often being used as confirmation of heroin use, 6-monoacetylmorphine (6-MAM) has limitations due to its short detection window. To compare the detection windows of heroin metabolites (morphine (MOR), 6-MAM, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G)) in human urine, an automated online solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and fully validated. The limits of detections (LODs) of the four metabolites were in the range of 1.25-5 ng/mL. Intra and inter-day precision for all the metabolites was 0.4-6.7% and 1.8-7.3%, respectively. Accuracy ranged from 92.9 to 101.7%. This method was then applied to the analysis of urine samples of 20 male heroin abusers. M3G was detected 9-11 days after admission to the drug rehabilitation institute in 40% of heroin users while MOR or M6G was not always detected. The detection window of M3G was thus the longest. Furthermore, M3G had a much higher concentration than MOR and M6G. Therefore, M3G could provide diagnostic information with regard to heroin exposure in the combination with other clues (e.g., heroin seizures at the scene).

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.

Fast, Sensitive, and Quantitative Point-of-Care Platform for the Assessment of Drugs of Abuse in Urine, Serum, and Whole Blood

Drug abuse is a major public health problem in many countries in Europe and North America. Currently available platforms for drug abuse assessment are facing technical challenges of nonquantitation, inaccuracy, low throughput, incompatibility with diverse complex specimens, long assay times, and requirement of instrument and/or expertise for readout. Here, we report an integrated competitive volumetric-bar-chart chip (CV-Chip) to assay multiple drug targets at the point-of-care (POC). To the best of our knowledge, it is the first time that a POC platform has been demonstrated to fully address the above-mentioned limitations. We applied this integrated CV-chip platform to assay multiple drugs in 38 patient urine and serum samples and validated the on-chip results with an LC-MS/MS method, indicating a clinical sensitivity and specificity of 0.94 and 1.00, respectively. We further demonstrated that the combination of an on-chip blood separator with the CV-Chip enabled the platform to directly assay finger-prick whole blood samples, which have always been recognized as an ideal biospecimen for POC detections. In summary, this integrated CV-Chip is able to serve as a sensitive, accurate, fast, portable, readout visible, and minimally invasive platform for drug abuse assessment.

Column switching UHPLC–MS/MS with restricted access material for the determination of CNS drugs in plasma samples

Background: Polypharmacy is a common practice in schizophrenia. Consequently, therapeutic drug monitoring is usually adopted to maintain the concentrations of the drugs in the plasma within a targeted therapeutic range, to maximize therapeutic efficiency and to diminish adverse side effects. Methodology: This study reports on a column switching UHPLC–MS/MS method to determine psychotropic drugs in plasma samples simultaneously. Results: The method was linear from 0.025 to 1.25 ng ml-1 with R2 above 0.9950 and the lack of fit test (p > 0.05). The precision values presented coefficients of variation lower than 12%, and the relative standard error of the accuracy were lower than 14%. Conclusion: The column switching UHPLC–MS/MS method developed herein successfully determined drugs in schizophrenic patients’ plasma samples for therapeutic drug monitoring.