Simple and sensitive screening and quantitative determination of 88 psychoactive drugs and their metabolites in blood through LC–MS/MS: Application on postmortem samples

Etizolam and Its Major Metabolites: A Short Review

Etizolam is a benzodiazepine (BZD). Etizolam is structurally different from BZDs as a thiophene replaces the benzene ring and a triazole ring is fused to the diazepine ring, but etizolam's pharmacological profile is similar. Etizolam has been used to treat anxiety and panic disorders, to reduce depressive and somatization symptoms and to induce muscle relaxation. Etizolam is used recreationally due to its reinforcing and sedative effects. Etizolam is available in tablet or powder form or administered on blotter paper that can be placed on the tongue for oral absorption. Etizolam metabolizes into two major metabolites: α-hydroxyetizolam and 8-hydroxyetizolam, and all three compounds can be detected in different biological specimens using various common analytical techniques such as immunoassay, chromatography and mass spectrometry. Etizolam is a controlled drug in many countries around the globe but is approved for medical use in some countries, such as Japan, South Korea and Italy. This work is a collation and review of available literature on etizolam to help improve the fundamental understanding of its toxicology, outline best analytical practice, and aid interpretation of toxicology results.

Stir bar sorptive-dispersive microextraction by a poly(methacrylic acid-co-ethylene glycol dimethacrylate)-based magnetic sorbent for the determination of tricyclic antidepressants and their main active metabolites in human urine

A poly(methacrylic acid-co-ethylene glycol dimethacrylate)-based magnetic sorbent was used for the rapid and sensitive determination of tricyclic antidepressants and their main active metabolites in human urine. This material was characterized by magnetism measurements, zeta potential, scanning electron microscopy, nitrogen adsorption-desorption isotherms, and thermogravimetric analysis. The proposed analytical method is based on stir bar sorptive-dispersive microextraction (SBSDME) followed by liquid chromatography-tandem mass spectrometry. The main parameters involved in the extraction step were optimized by using the response surface methodology as a multivariate optimization method, whereas a univariate approach was employed to study the desorption parameters. Under the optimized conditions, the proposed method was properly validated showing good linearity (at least up to 50 ng mL-1) and enrichment factors (13-22), limits of detection and quantification in the low ng L-1 range (1.4-7.0 ng L-1), and good intra- and inter-day repeatability (relative standard deviations below 15%). Matrix effects were observed for the direct analysis of urine samples, but they were negligible when a 1:1 v/v dilution with deionized water was performed. Finally, the method was successfully applied to human urine samples from three volunteers, one of them consuming a prescribed drug for depression that tested positive for clomipramine and its main active metabolite. Quantitative relative recoveries (80-113%) were obtained by external calibration. The present work expands the applicability of the SBSDME to new analytes and new types of magnetic sorbents.

Novel extraction method using an ISOLUTE PLD+ protein and phospholipid removal column for liquid chromatography-tandem mass spectrometry analysis of 20 psychoactive drugs in postmortem whole blood samples

A novel sample extraction method using an ISOLUTE PLD+ protein and phospholipid removal column was developed for simultaneous quantification of 20 psychoactive drugs, including antidepressants, antipsychotics, sedative-hypnotics, and amphetamines, in postmortem whole blood samples by liquid chromatography-tandem mass spectrometry. The method showed improvement in extract cleanliness compared with traditional protein precipitation and the QuEChERS extraction method. The method was validated for all analytes; the calibration curves showed good linearity, with r² values exceeding 0.991. The intra- and interday accuracies and precisions were 87.6-117.5% and 1.0-18.6%, respectively. The recovery efficiencies were in the range of 64.6-96.8%. Matrix effects were observed in the range of 82.6-116.0%. All analytes were stable under different storage conditions. This method was successfully applied in postmortem forensic sample analysis to quantify psychoactive drugs. The method described in the current study will be useful for forensic toxicological investigations.

Multi-analyte LC-MS/MS quantification of 38 antipsychotics and metabolites in plasma: Method validation & application to routine analyses

The past decades have seen a rise in the prescription of antipsychotic drugs in the European population, despite the risk of extra-pyramidal, metabolic and cardiac side effects. A multi-analyte liquid chromatography - triple quadrupole mass spectrometry method was developed for the quantification of 38 antipsychotic drugs in plasma. Samples were extracted by a straightforward liquid-liquid extraction with methyl-tertiary-butyl-ether and the compounds of interest were chromatographically separated within 6 min. Calibration curves covered the recommended therapeutic range for all compounds, in addition to sub- and supratherapeutic concentrations for most. The method was successfully validated according to the European Medicines Agency guidelines on bioanalytical method validation. Analysis of medico-legal samples confirmed the relatively common use of the second generation antipsychotics quetiapine and olanzapine, as well as the continued presence of the first generation antipsychotic haloperidol.

Distribution of Fluvoxamine and Identification of the Main Metabolite in a Fatal Intoxication

Fluvoxamine is a selective serotonin reuptake inhibitor, with a half-life of about 30 hours, that is commonly prescribed in the treatment of depression and obsessive and compulsive disorders. Though its more favorable adverse effect profile in comparison to tricyclic antidepressants, overdosages could lead to severe central nervous system depression. We hereby report the case of a 48-year-old woman with psychiatric disorders, who died in the Protected Community where she lived. An autopsy, during which multiorgan congestion and aspiration of gastric content were found, was performed 9 days after the death. Femoral and cardiac blood, urine and bile were collected for toxicological analysis. GC-MS, LC-MS-MS and LC-HRMS screenings were performed on blood samples. The analysis allowed to identify the following drugs: fluvoxamine, clotiapine, 7-aminoclonazepam, propranolol, gabapentin and haloperidol. Quantification of the detected drugs in blood was performed by means of a validated LC-MS-MS analytical procedure, and the following results were achieved: fluvoxamine (2.20 mg/L), gabapentin (41.00 mg/L), 7-aminoclonazepam (0.24 mg/L), clotiapine (0.07 mg/L), haloperidol (<0.01 mg/L) and propranolol (0.24 mg/L). Fluvoxamine concentration in blood exceeded ~10 times the upper limit of therapeutic blood levels (0.23 mg/L). Contributory causes of death, such as due to multiple drug use, however, cannot be excluded. The distribution of fluvoxamine in all biological fluids was evaluated and a postmortem redistribution effect was observed (C/P blood ratio: 1.86). Fluvoxamine acid metabolite was identified in urine, bile and in cardiac blood, through an LC-QTOF analytical procedure.

Development, validation, and application of a simple UPLC-MS/MS method for simultaneous quantification of five traditional antipsychotics in human plasma

A UPLC-MS/MS method was developed to determine the levels of five traditional antipsychotics (APs) (chlorprothixene, perphenazine, fluphenazine, thioridazine, and promethazine) in human plasma with carbamazepine as the internal standard. Samples were extracted using simple liquid-liquid extraction (ethyl acetate/methyl tert-butyl ether, 2:3 v/v); then the analytes were subjected to gradient elution chromatography with a mobile phase composed of 0.1% formic acid in water and acetonitrile. The analytes were separated using a Waters XBridge BEH C₁₈ column (100 × 2.1 mm, 2.5 μm). The linear ranges of chlorprothixene, perphenazine, fluphenazine, thioridazine, and promethazine are 2-250 ng/mL, r > 0.995. The limit of quantitation is 2 ng/mL, and the limit of detection is in the range of 0.1-0.5 ng/mL. The inter-day and intra-day relative standard deviations are less than 10%, and the relative errors are in the range of -5.70 to 7.20%. The recoveries of the five drugs are in the range of 70-109%. The results of methodology verification indicate that this method is simple, economical, sensitive, and suitable for the simultaneous quantification of five traditional APs in human plasma.

Quantification of 54 Benzodiazepines and Z-Drugs, Including 20 Designer Ones, in Plasma

Benzodiazepines are widely used in the treatment of sleep and anxiety disorders, as well as epileptic seizures and alcohol withdrawal because of their broad therapeutic index and low cost. Due to their central nervous system depressant effects they are also often implicated in traffic accidents and drug-related intoxications. With an increasing number of designer benzodiazepines used in a recreational setting, there is a need for analytical methods to be able to quantify both the prescribed and designer benzodiazepines. A liquid chromatography-triple quadrupole mass spectrometry method was developed for the quantification of 34 prescribed and 20 designer benzodiazepines in plasma. Different sample preparation strategies, including protein precipitation, liquid-liquid extraction, solid-phase extraction and mini-QuEChERS, were tested. The best recoveries for all compounds of interest were obtained with a liquid-liquid extraction using methyl-tertiary-butyl-ether and 500 μL plasma. The method was fully validated according to the European Medicines Agency guidelines for all compounds, except pivoxazepam, which is included for qualitative purposes only. In-sample stability issues were observed for cloxazolam, both at ambient temperature and during long-term storage at -20°C. Due to the large number of compounds included, the simple and time-efficient sample preparation and the relatively inexpensive instrumentation used, the presented method can be readily implemented in both therapeutic drug monitoring and forensic analyses.

LC-MS-MS Determination of 25 Antipsychotic Drugs and Metabolites in Urine for Medication Compliance Monitoring

A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed for 25 antipsychotic drugs and their metabolite in urine for monitoring medication compliance of mentally disordered criminals on probation. Target compounds were extracted with a solid-phase extraction technique using a newly developed hydrophilic-lipophilic balanced sorbent to remove interferences and minimize the matrix effect (ME). Extracted sample was injected into the LC-MS-MS with an electrospray ionization source in positive mode and multiple-reaction monitoring mode. The analytes were separated and detected within 10 minutes using a reversed-phase column with a gradient elution method using 0.1% formic acid in water and 0.1% formic acid in methanol as mobile phase. The validation parameters were evaluated as follows: selectivity, limit of detection, lower limit of quantification (LLOQ), linearity, accuracy and precision, stability, dilution integrity, recovery (RE), ME and process efficiency (PE). The LLOQs were 0.1 to 2.0 ng/mL, and determination coefficients of the calibration curve were above 0.9943 over the concentration ranges. The intra-and inter-day accuracy ranged from -10.4% to 9.9% and from -9.6% to 9.4%, while the intra-and inter-day precision were within 10.7% and 9.9%. The bench-top and long-term stability ranged from 92.1% to 109.5% and 88.7% to 111.6%, respectively. The reproducibility of auto-sampler stability was <10% for all analytes. The accuracy and precision of dilution integrity ranged from -11.7% to 10.5% and 0.4% to 9.9%, respectively. The relative standard deviation of RE and ME was from 0.6% to 6.6% and 0.5% to 3.9%, respectively, while that of PE was 1.3% to 4.5%. The developed LC-MS-MS method for medication compliance monitoring was successfully applied to urine samples from mentally disordered probationers and determined to be one of effective ways for preventing the recurrence of mentally disordered crimes.

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.

Recent Advances in the HPLC Analysis of Tricyclic Antidepressants in Bio-Samples

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Tricyclic Antidepressants (TCAs) are a group of the main category of antidepressant drugs, which are commonly prescribed to treat major depressive disorder. Determination of TCA drugs is very important for clinical and forensic toxicology, especially for therapeutic drug monitoring in various biofluids. High Performance Liquid Chromatography (HPLC) is a well-established technique for this purpose. A lot of progress has been made in this field since the past 10 years. Novel extraction techniques, and novel materials for sample preparation, novel columns and novel applications of analysis of various biofluids for the determination of TCAs in combination with other drugs are some typical examples. Moreover, advances have been performed in terms of Green Analytical Chemistry principles. Herein, we aim to discuss the developed HPLC methods that were reported in the literature for the time span of 2008-2018.

Development and validation of solid-phase extraction coupled with a liquid chromatography-tandem mass spectrometry method for quantitation of olanzapine in saliva

Olanzapine is one of the most commonly used drugs for the treatment of schizophrenia and depression of various origins. Its levels are usually measured in the blood, but the collection of this diagnostic material poses many problems. Therefore, we aimed to develop a fast and sensitive method to determine olanzapine levels in saliva, an easily available diagnostic material. To reduce the consumption of toxic solvents during analyte extraction from saliva, olanzapine was isolated by solid-phase extraction using Oasis® MCX cartridges. Chromatographic analysis was performed by LC-MS/MS, with C18 resin in Atlantis® T3 column as the stationary phase and 2 mM ammonium formate and acetonitrile as the mobile phase (flow rate of 0.25 mL/min, with elution gradient). The specificity, linearity, sensitivity, precision, accuracy, and stability of the optimized method were validated. The relative standard deviation for intra-day precision for three tested olanzapine concentrations did not exceed 12.7%; the highest accuracy value was 113.9%. The recoveries from spiked saliva samples were greater than 87.3% for the two olanzapine concentrations studied. The developed method was then used to determine olanzapine levels in human saliva obtained from 15 patients treated with different doses of olanzapine.

Determination of Antidepressants and Antipsychotics in Dried Blood Spots (DBSs) Collected from Post-Mortem Samples and Evaluation of the Stability over a Three-Month Period

An LC-MS/MS method for the identification and quantification of antidepressants and antipsychotics was developed on dried blood spots (DBSs). Moreover, analyte stability on DBSs within a 3-month period was monitored. Aliquots of 85 µL of blood from autopsy cases were pipetted onto DBS cards, which were dried and stored at room temperature. DBSs were analyzed in triplicate immediately, within the following 3 weeks, and after 3 months. For each analysis, a whole blood stain was extracted in phosphate buffer and purified using Solid Phase Extraction (SPE) cartridges in order to avoid matrix effects and injected in the LC-MS/MS system. Thirty-nine molecules were screened. Limits of detection (LODs) ranged between 0.1 and 3.2 ng/mL (g) and 0.1 and 5.2 ng/mL (g) for antidepressants and antipsychotics, respectively. Limits of quantification (LOQs) varied from 5 to 10.0 ng/mL for both. Sixteen cases among the 60 analyzed resulted positive for 17 different analytes; for 14 of these the method was fully validated. A general good agreement between the concentrations on DBSs and those measured in conventional blood samples (collected concurrently and stored at -20 °C) was observed. The degradation/enhancement percentage for most of the substances was lower than 20% within the 3-month period. Our results, obtained from real post-mortem cases, suggest that DBSs can be used for routine sample storage.

A fast and simple approach for the quantification of 40 illicit drugs, medicines, and pesticides in blood and urine samples by UHPLC-MS/MS

A fast and simple approach to overcome challenges in emergency toxicological analysis, using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) has been developed, for the detection of analytes in blood and urine samples from the following drug classes: analgesics, benzodiazepines, antidepressants, anticonvulsants, drugs of abuse, and pesticides. These substances are relevant in the context of emergency toxicology in Brazil. The sample preparation procedure was relatively easy and fast to perform. The method was fully validated giving limits of in the range of 0.5 and 20 ng mL^-1 for blood and urine samples. The intraday and interday precision and accuracy were considered adequate for all analytes once the relative standard deviation (RSD) (%) was lower than 20% for quality control (QC) low and lower than 15% for CQ medium and high. The developed method was successfully applied to 320 real samples collected at the Poison Control Center of São Paulo, and 89.1% have shown to be positive for some of the analytes. This confirms its applicability and importance to emergency toxicological analysis, and it could be very useful in both fields of clinical and forensic toxicology.

Applications of Gas Chromatography for the Analysis of Tricyclic Antidepressants in Biological Matrices

Tricyclic antidepressant drugs (TCAs) are a main category of antidepressants, which are until today widely used for the treatment of psychological disorders due to their low cost and their high efficiency. Therefore, there is a great demand for method development for the determination of TCAs in biofluids, especially for therapeutic drug monitoring. Gas chromatography (GC) was the first chromatographic technique implemented for this purpose. With the recent development in the field of sample preparation, many novel GC applications have been developed. Herein, we aim to report the recent application of GC for the determination of tricyclic antidepressants in biofluids. Emphasis is given to novel extraction techniques and novel materials used for sample preparation.

Reference Brain/Blood Concentrations of Citalopram, Duloxetine, Mirtazapine and Sertraline

Postmortem blood samples may not accurately reflect antemortem drug concentrations, as the levels of some drugs increase due to postmortem redistribution (PMR). The brain has been suggested as an alternative sampling site. The anatomically secluded site of the brain limits redistribution and prolongs the detection window, thereby enabling sampling from deceased individuals where blood is no longer suitable for analysis. We report concentrations in brain tissue and blood from 91 cases for the four antidepressants citalopram, duloxetine, mirtazapine and sertraline. The cases were classified according to their role in the cause of death, as follows: (A) concentrations where the drug was the sole cause of fatal intoxication; (B) concentrations where the drug contributed to a fatal outcome; and (C) concentrations where the drug was not related to the cause of death. The analytical method was successfully validated in brain tissue in terms of linearity, process efficiency, precision and accuracy. Quantification of analytes was performed by ultra-performance liquid chromatography with tandem mass spectrometry. Correlations between blood and brain concentrations were achieved with R2-values between 0.67 and 0.91. The following median brain-blood ratios were obtained: 3.71 for citalopram (range: 1.4-5.9), 11.0 for duloxetine (range: 5.0-21.6), 1.53 for mirtazapine (range: 1.02-4.71) and 7.38 for sertraline (range: 3.2-14.2). The S/R ratio of racemic citalopram was the same in brain (0.80) and blood (0.85), whereas the median citalopram/N-desmethylcitalopram ratio was higher in brain (9.1) than blood (4.1). The results of this study may serve as reference concentrations in brain for forensic cases.

Simultaneous determination of 18 psychoactive agents and 6 metabolites in plasma using LC-MS/MS and application to actual plasma samples from conscription candidates

In Korea, an increasing number of people attempt to evade military conscription by posing as mental health patients. To verify the authenticity of mental illness, there is a need to detect wide range of psychoactive agents in biological specimens of conscription candidates. In this study, we developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of 18 psychoactive agents and 6 metabolites in human plasma. The method was characterized by the use of a simple, fast and cheap protein precipitation as sample preparation, a rapid run time (11min) and a low volume of plasma sample (200μL). The analytes were monitored under the scheduled multiple reaction monitoring (sMRM) positive and negative mode using electrospray ionization (ESI). The essential validation parameters including selectivity, linearity, accuracy, precision, matrix effect and recovery were satisfactory. The limit of detection ranged from 0.0005 to 0.001μg/mL, and limit of quantitation ranged from 0.005 to 0.025μg/mL. The developed method was successfully applied to 323 actual plasma samples submitted by Korea central physical examination center of military manpower administration in 2016, and is expected to contribute to the rapid and accurate disposition of military service.

Development and validation of an LC-ESI-MS/MS method for the quantification of D-84, reboxetine and citalopram for their use in MS Binding Assays addressing the monoamine transporters hDAT, hSERT and hNET

MS Binding Assays represent a label-free alternative to radioligand binding assays. In this study, we present an LC-ESI-MS/MS method for the quantification of (R,R)-4-(2-benzhydryloxyethyl)-1-(4-fluorobenzyl)piperidin-3-ol [(R,R)-D-84, (R,R)-1], (S,S)-reboxetine [(S,S)-2], and (S)-citalopram [(S)-3] employed as highly selective nonlabeled reporter ligands in MS Binding Assays addressing the dopamine [DAT, (R,R)-D-84], norepinephrine [NET, (S,S)-reboxetine] and serotonin transporter [SERT, (S)-citalopram], respectively. The developed LC-ESI-MS/MS method uses a pentafluorphenyl stationary phase in combination with a mobile phase composed of acetonitrile and ammonium formate buffer for chromatography and a triple quadrupole mass spectrometer in the multiple reaction monitoring mode for mass spectrometric detection. Quantification is based on deuterated derivatives of all three analytes serving as internal standards. The established LC-ESI-MS/MS method enables fast, robust, selective and highly sensitive quantification of all three reporter ligands in a single chromatographic run. The method was validated according to the Center for Drug Evaluation and Research (CDER) guideline for bioanalytical method validation regarding selectivity, accuracy, precision, calibration curve and sensitivity. Finally, filtration-based MS Binding Assays were performed for all three monoamine transporters based on this LC-ESI-MS/MS quantification method as read out. The affinities determined in saturation experiments for (R,R)-D-84 toward hDAT, for (S,S)-reboxetine toward hNET, and for (S)-citalopram toward hSERT, respectively, were in good accordance with results from literature, clearly demonstrating that the established MS Binding Assays have the potential to be an efficient alternative to radioligand binding assays widely used for this purpose so far.

Death of a seven-month-old child in a washing machine: a case report

The authors present a case which brings out a unique modality of child homicide by placing the baby in a washing machine and turning it on. The murder was perpetrated by the baby's mother, who suffered from a serious depressive disorder. A postmortem RX and then a forensic autopsy were performed, followed by histologic examinations and toxicology. On the basis of the results of the autopsy, as well as the histology and the negative toxicological data, the cause of death was identified as acute asphyxia. This diagnosis was rendered in light of the absence of other causes of death, as well as the presence of typical signs of asphyxia, such as epicardial and pleural petechiae and, above all, the microscopic examinations, which pointed out a massive acute pulmonary emphysema. Regarding the cause of the asphyxia, at least two mechanisms can be identified: drowning and smothering. In addition, the histology of the brain revealed some findings that can be regarded as a consequence of the barotrauma due to the centrifugal force applied by the rotating drum of the washing machine. Another remarkable aspect is that we are dealing with a mentally-ill assailant. In fact, the baby's mother, after a psychiatric examination, was confirmed to be suffering from a mental illness-a severe depressive disorder-and so she was adjudicated not-guilty-by-reason-of-insanity. This case warrants attention because of its uniqueness and complexity and, above all, its usefulness in the understanding of the pathophysiology of this particular manner of death.

Rapid analysis of drugs of abuse and their metabolites in human urine using dilute and shoot liquid chromatography-tandem mass spectrometry

Liquid chromatography-tandem mass spectrometric method for analysis of 113 abuse drugs and their metabolites in human urine was developed and validated. A simple sample clean-up procedure using the "dilute and shoot" approach, followed by reversed phase separation, provided a fast and reliable method for routine analysis. Drugs were separated in a Capcell Pak MG-III C₁₈ column using a gradient elution of 1 mM ammonium formate with 0.1% formic acid in water and acetonitrile. The total time for analysis was 32 min. The multiple reaction monitoring mode using two transitions (e.g., quantifier and qualifier) was optimized for both identification and determination. The calibration curves for each analyte were linear over the concentration ranges of 1-100, 5-100, or 10-100 ng/mL using 400 μL of human urine sample with the coefficient of determination above 0.9921. The coefficient of variation and accuracy for the intra- and inter-assays of the tested drugs at three QC levels were 1.1-14.6 and 86.7-106.8%, respectively. The present method was successfully applied to the analysis of forensic urine samples obtained from 17 drug abusers. This method is useful for the rapid and accurate determination of multiple drug abuse with a small amount of urine in forensic and clinical toxicology.