Development of a Liquid Chromatography-Tandem Mass Spectrometry Method for the Simultaneous Determination of 40 Drugs of Abuse in Human Urine: Application to Real Cases

Drugs of abuse are constantly evolving, while new synthetized substances are constantly emerging to avoid regulations. However, traditional drugs such as cocaine and amphetamine are still two of the most consumed drugs in the world. It is important, therefore, to provide suitable multiresidue methods for determining a wide range of drugs for use in toxicological and forensic analyses. The aim of this study is to develop a method for determining several families of drugs of abuse, including classic drugs, new psychoactive substances and some of their metabolites, in urine by liquid chromatography-tandem mass spectrometry. Urine is one of the most common biological matrices used in drug analysis because of its easy collection and a wide window of detection. In this study, we used solid-phase extraction to remove interferences and extract analytes from urine. Four different mixed-mode cation-exchange commercial sorbents were evaluated. The best results, in terms of apparent recoveries, were achieved with one of the strong cationic sorbents, ExtraBond SCX. The method achieved detection limits from 0.003 to 0.500 ng/mL and quantification limits from 0.050 to 1.500 ng/mL, which are suitable for determining these compounds at the usual levels found in the urine of drug users. The applicability of this method was demonstrated by analyzing real urine specimens from women following a detoxification program. Our results showed that the drug most consumed was cocaine, since it was detected in most urine specimens together with its main metabolite, benzoylecgonine. The polyconsumption of drugs from different families was also observed in some urine samples analyzed.

Novel Matrix Normalization Technique for Accurate LC-ESI-MS/MS Detection and Quantification of Drugs and Their Metabolites in Toxicology Research and Practice

Accurate identification and quantification of drugs and their metabolites (analytes) in biological matrices is an analytical foundation of clinical and forensic toxicology. For decades, liquid chromatography interfaced by electrospray ionization with tandem mass spectrometry (LC-ESI-MS/MS) has been a widely used technology for analysis in the field of toxicology, as well as in many other fields of bioscience. It is also known that ion response in LC-ESI-MS/MS analysis is influenced by coeluting biological compounds and that preanalytical sample clean-up is often insufficient in removing these interferences. As a result, a normalization technique is commonly used for assessment and compensation of matrix effects encountered in routine analysis. Internal standardization with a stable isotope analog of the analyte is the predominant normalization technique used in LC-ESI-MS/MS analysis. The technique, however, requires commercial availability or costly custom synthesis of an isotopic analog specific for each analyte. Here we describe an alternative technique for matrix normalization for use in high-volume, multianalyte testing without the need for isotope analogs. The technique involves analysis of the original sample (neat analysis) followed by analysis of a second sample aliquot (spike analysis) that has been fortified with a controlled amount of reference analyte. A calibration procedure similar to internal standardization is employed, using an ion response ratio of neat to fortified analyte. As a demonstration of the technique in multianalyte testing, we provide a detailed protocol for simultaneous detection and quantification of 102 drugs and drug metabolites in human urine. We also provide a support protocol for addition of new analytes to the multianalyte panel, allowing convenient collection of the validation data during routine testing. The matrix normalization technique and testing principles may be applicable to a wide range of analytes and biological matrices, not only those encountered in toxicology but also in other fields of bioscience. © 2023 Wiley Periodicals LLC. Basic Protocol: Detection and quantification of 102 toxicology analytes in urine by LC-ESI-MS/MS analysis using the threshold accurate calibration technique Support Protocol: Method for addition and validation of new analytes to expand the Basic Protocol.

Homemade Pipette Tip Solid-Phase Extraction for the Simultaneous Determination of 40 Drugs of Abuse in Urine by Liquid Chromatography–Tandem Mass Spectrometry

Pipette tip solid-phase extraction facilitates the handling of low-volume samples and organic solvents in order to achieve more environmentally friendly pre-treatment sample techniques. The use of pipette tip extraction was examined for the quick and simple determination of a heterogeneous group of 40 drugs of abuse and some of their metabolites in urine by liquid chromatography coupled to tandem mass spectrometry. Several parameters were studied and optimized, including those which can affect extraction efficiencies, such as the amount of sorbent and the volumes and number of aspirating/dispensing cycles of the sample and organic solvents. The linear range of this method was between the quantification limit and 75 or 100 ng mL−1. Detection limits between 0.025 and 0.500 ng mL−1 and quantification limits from 0.100 to 1.500 ng mL−1 were achieved, which are adequate to determine the studied compounds in urine from drug users. Finally, in order to prove its suitability in toxicological and forensic analyses, the method was successfully applied to 22 urine specimens from women who were starting a detoxification program. Cocaine was the most frequently detected substance, as its presence or the presence of its main metabolite was found in 86% of the analyzed samples.

Application and Clinical Value of Definitive Drug Monitoring in Pain Management and Addiction Medicine

OBJECTIVE

To assess routine application and clinical value of definitive urine drug monitoring (UDM) for drug detection, inconsistent drug use and prescription adherence, along with a comparison to immunoassay screening (IAS).

METHODS

Direct-to-definitive UDM performance was analyzed retrospectively in 5,000 patient specimens. Drug findings, medication inconsistencies and detection sensitivity were assessed, and definitive UDM versus IAS monitoring was studied.

RESULTS

Definitive testing resulted in 18,793 drug findings with 28,403 positive drug and metabolite tests. Definitive testing expanded monitoring with 11,396 drug findings that would not be tested by IAS. The opioids accounted for the highest frequency of inconsistent positive drug-use findings, at 12%. Conversely, inconsistent negative drug findings, used as an index of prescription non-adherence, were determined in 1,751 of 15,409 monitored medications and included a high frequency of antidepressants and antipsychotics inconsistencies. Direct comparison of definitive UDM and IAS showed false-positives by IAS as well as a high rate of false-negatives that would be missed using current confirmation protocols.

CONCLUSIONS

Results from routine application of direct-to-definitive UDM demonstrate the clinical value of drug-use identification and objective evaluation of inconsistencies in drug misuse and medication adherence in pain management and addiction medicine practice. Without conversion to direct-to-definitive UDM, continuing use of IAS will limit the scope of drugs being tested, will result in an indeterminate rate of false negatives and will require confirmation testing to eliminate the reporting of false positive IAS tests. The findings in this study provide evidence-based support for recommended use of a direct-to-definitive drug testing protocol.

Matrix Normalization Techniques for Definitive Urine Drug Testing

Analytical performance of stable isotope labeled internal standardization (SIL-IS) and threshold accurate calibration (TAC) methods of matrix normalization are compared for quantitation of 51 drugs and metabolites (analytes) in urine with analysis by UPLC-MS-MS. SIL-IS was performed with both analyte-specific (ASIL-IS) and shared (SSIL-IS) internal standards. Variance in inter-specimen matrix effect, without use of a matrix normalization method, was studied by UPLC-MS-MS (Ultra Performance Liquid Chromatography with tandem mass spectrometry) analysis of 338 urine donor samples and showed over 200% variation in ion response for some analytes. Matrix normalization methods were evaluated for precision, accuracy, calibration, multi-matrix recovery and positive casework quantitation. Acceptable calibration and quality control criteria were achieved for all methods when calibrators and controls were prepared from the same urine matrix pool. Quantitative accuracy, determined by addition of analytes to multi-donor urine pools at two concentration levels, resulted in acceptable percent relative standard deviation (%RSD) and bias for TAC and ASIL-IS methods. SSIL-IS method quantitations in analyte-supplemented donor pools revealed a %RSD ranging from 20-60% for more than 30% of the analytes and a method bias that ranged up to 87%, with a differential matrix effect on analyte and shared internal standard accounting for the imprecision and bias. Analyte quantitation in 162 authentic case samples showed close agreement for TAC and ASIL-IS methods, with greater variance in the SSIL-IS method. The study demonstrates effective matrix normalization by ASIL-IS and TAC methods and a matrix-caused bias in the SSIL-IS method.

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.

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.