Detection and Analysis of Blood Dexmedetomidine in Drug-Facilitated Cases.

OBJECTIVES: To establish a simple and rapid qualitative and quantitative detection method of dexmedetomidine in blood. METHODS: Blood was separated on the Allure PFP Propyl liquid chromatography column with isocratic elution after it was precipitated by acetonitrile and filtered. Qualitative and quantitative analysis of dexmedetomidine was performed using positive ion scan mode and multi-reaction monitoring mode. RESULTS: The limit of detection of dexmedetomidine in blood was 0.2 ng/mL and the limit of quantification was 0.5 ng/mL. The linearity of the method was good in the range of 0.5-1 000 ng/mL, and the correlation coefficient was greater than 0.99. The accuracy of the method was 90.34%-112.67% and the extraction recovery was 50.05%-91.08%, with no significant matrix effect. CONCLUSIONS: This method is simple, selective and suitable for the qualitative and quantitative analysis of dexmedetomidine in blood, which can provide a reference for drug-facilitated cases involving dexmedetomidine.

Discrimination of Traditional Chinese Medicine Syndromes in Type 2 Diabetic Patients Based on Metabolomics-Proteomics Profiles.

Materials and Methods: The metabolomics-proteomics of sixty patients with T2DM were acquired by high-performance liquid chromatography (HPLC). In addition, some clinical features, containing total cholesterol (TC), triglycerides (TG), hemoglobin A1c (HbA1c), body mass index (BMI), and low-density lipoprotein (LDL) together with high-density lipoprotein (HDL), were determined via clinical detection strategies. Abundant metabolites and proteins, respectively, were identified with the analysis of liquid chromatography tandem mass spectrometry (LC-MS/MS). Results: 22 differentially abundant metabolites and 15 differentially abundant proteins were determined. The analysis of bioinformatics suggested that the differentially abundant proteins were commonly associated with the renin-angiotensin system, vitamin digestion and absorption, hypertrophic cardiomyopathy, and so on. Furthermore, differentially abundant metabolites were amino acids and were associated with the biosynthesis of CoA and pantothenate, together with the metabolisms of phenylalanine, beta-alanine, proline, and arginine. Combination analysis revealed that the vitamin metabolism pathway was predominantly affected. Conclusions: DHS syndrome can be separated by certain metabolic-proteomic differences, and metabolism is particularly prominent, especially in vitamin digestion and absorption. From the molecular level, we provide preliminary data for the extensive application of TCM in the study of T2DM, and at the same time benefited in a sense diagnosis and treatment of T2DM.

Forensic Analysis of 9 Poisoning Death Cases Caused by Oral Administration of Diphenidol.

OBJECTIVES: To analyze the characteristics of diphenidol poisoning cases and to provide clues and technical means for the identification of such cases. METHODS: Biological samples of 9 deaths caused by diphenidol poisoning were detected by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and the characteristics of these cases were analyzed retrospectively. RESULTS: Most of the deaths caused by diphenidol poisoning were young females. The dosage was between 60 and 300 tablets, and the mass concentration of diphenidol in the postmortem blood ranged from 0.87 to 99.00 µg/mL. There was no correlation between the dosage and the concentration of diphenidol in the blood. CONCLUSIONS: Diphenidol poisoning has the characteristics of high concealment and lethality. More attention should be paid to suicide cases, and diphenidol should be recommended as a routine detection item to avoid missing detection.

Strategies for Collection and Analysis of Samples in Simple Asphyxiant Gas Acute Poisoning Death Cases.

At present, the death cases of simple asphyxiant gas acute poisoning are increasing sharply. Common asphyxiant gases in death cases include nitrogen, helium, carbon dioxide, methane, propane, laughing gas, etc. Simple asphyxiant gas has no affinity for biological matrices and escapes quickly, which puts forward new requirements for autopsy procedures, selection and collection of samples, laboratory analysis and identification. This paper reviews the research and development process of death cases caused by simple asphyxiant gas acute poisoning and put forwards the collection and analysis strategy of the samples in such cases. The most valuable biological samples in such cases should be lung tissues associated with the airways, followed by brain tissue and cardiac blood. Gaseous samples from the esophageal cavity, tracheal cavity, pulmonary bronchi, gastric and cardiac areas are also recommended as valuable samples. In the case of postmortem examination, the gas should be injected into gas sample bag directly. Biological materials such as tissue and blood should be directly sealed in head-space vials and analyzed by using the headspace gas chromatography-mass spectrometry.

Analysis of the Distribution of Total Phosphine and the Characteristics of Phosphine Poisoning in 29 Victims.

OBJECTIVES: To study the distribution of total phosphine in phosphine poisoning victims and summarize the characteristics of phosphine poisoning cases. METHODS: The phosphine and its metabolites in the biological samples of 29 victims in 16 phosphine poisoning cases were qualified and quantified by headspace gas chromatography-mass spectrometry. RESULTS: Five victims among 29 were poisoned by ingestion of aluminium phosphide and 24 by inhalation of phosphine gas. Phosphine metabolites were detected in the biological samples of 23 victims, and the concentrations of total phosphine in blood ranged 0.5-34.0 µg/mL. The total concentration of phosphine in liver tissue was up to 71.0 µg/g. Phosphine was not detected in the blood of the other six survived victims, which may be related to the small amount of phosphine exposure and the delay in blood sampling. CONCLUSIONS: The total concentration of phosphine in blood and tissues caused by aluminum phosphine ingestion is higher than that caused by phosphine gas inhalation. The death cases of phosphine inhalation are characterized by long exposure time, repeated exposures and age susceptibility.

Determination of twenty herbicides in blood by ultrapressure liquid chromatography-tandem mass spectrometry.

A sensitive and rapid method for the simultaneous determination of twenty herbicides (aclonifen, lactofen, terbutryn, butylate, carbetamide, fluazifop-P-butyl, propanil, prometryn, isoproturon, terbumeton, pretilachlor, pendimethalin, cycloxydim, tri-allate, metolachlor, diuron, alloxydim, prosulfuron, triflusulfuron-methyl, and acetochlor) in human blood is reported herein. Liquid-liquid extraction coupled with ultra-pressure liquid chromatography-tandem mass spectrometry was employed for the simultaneous analysis of all compounds in 15 min. Validation parameters were studied through the estimation of the limits of detection and quantification, calibration curves, sensitivity, spiked recovery and precision. The limits of detection ranged from 0.1 to 1.0 ng/mL. The limits of quantification ranged from 0.5 to 2.0 ng/mL. Good linearity was obtained for all compounds with R2> 0.99 in all cases. Furthermore, interday precision (< 15%) and intraday precision (< 15%) were shown to be satisfactory. Recoveries in spiked blood samples were evaluated, and acceptable values (88.0%~108.8%) were found. Finally, this method was successfully applied to the determination of fluazifop-P-butyl, isoproturon and acetochlor in blood samples from real forensic cases. These results suggest that this method is reliable for rapid forensic and clinical diagnosis.

Analysis of 28 hair samples from users of the hallucinogenic beverage ayahuasca.

Ayahuasca is a psychoactive beverage widely used in religious ceremonies in Amazonia. Dimethyltryptamine is the main active compound of ayahuasca. Dimethyltryptamine has many hazardous effects, including hallucinations. In the present study, a fast and reliable UPLC-MS/MS method was developed and validated for the quantitation of dimethyltryptamine in hair samples. Twenty-milligram hair samples were pulverized with methanol below 4 °C. After ultrasonication, centrifugation and filtration, 200 µL of supernatant was placed into an autosampler vial for LC-MS/MS analysis. The lower limit of quantitation (LLOQ) was 3 pg/mg. The resulting calibration curve for dimethyltryptamine fit the expression y = 281.50213x + 0.00231 (R2 = 0.992). Acceptable intraday and interday precision (RSD < 15%) and accuracy (92-113%) were achieved. The dilution integrity was deemed acceptable based on accuracy (96%) and precision (1.8%). The validated method was successfully applied to 28 forensic cases. The concentrations of dimethyltryptamine ranged from 3 to 1109 pg/mg.

Metabolism of 4F-MDMB-BICA in zebrafish by liquid chromatography-high resolution mass spectrometry.

In this study, in vivo metabolic studies of the synthetic cannabinoid 4F-MDMB-BICA were investigated using zebrafish models. The metabolites were identified and structurally illustrated by liquid chromatography-high resolution mass spectrometry. Fourteen phase-I metabolites and four phase-II metabolites were generated from zebrafish. The main metabolic pathways of the phase-I metabolism included N-dealkylation, N-dealkylation combined with hydroxylation, amide hydrolysis, oxidative defluorination, oxidative defluorination to butyric acid, acetic acid formation at the indole side chain, hydroxylation, ester hydrolysis followed by hydroxylation, dehydrogenation, dehydrogenation, and N-dealkylation, and oxidative defluorination subsequently combined with dehydrogenation. The main biotransformations of the phase-II metabolism were glucuronidation and sulfation. Two phase-I metabolites (A1 and A11) and four phase-II metabolites (A2, A3, A4, and A12) were reported for the first time. A14, which was confirmed in human biological samples, was detected only in zebrafish samples but not found in human liver microsome incubation study. The current study indicates that the zebrafish model is a promising tool for elucidating the metabolism of NPS in the future.

Identifying metabolites of diphenidol by liquid chromatography-quadrupole/orbitrap mass spectrometry using rat liver microsomes, human blood, and urine samples.

In recent years, diphenidol [1,1-diphenyl-4-piperidino-1-butanol] has been one of the drugs that appears in suicide cases, but there are few research data on its metabolic pathways and main metabolites. Metabolite identification plays a key role in drug safety assessment and clinical application. In this study, in vivo and in vitro samples were analyzed with ultra-high-performance liquid chromatography-quadrupole/electrostatic field orbitrap high-resolution mass spectrometry. Structural elucidation of the metabolites was performed by comparing their molecular weights and product ions with those of the parent drug. As a result, 10 Phase I metabolites and 5 glucuronated Phase II metabolites were found in a blood sample and a urine sample from authentic cases. Three other Phase I metabolites were identified in the rat liver microsomes incubation solution. The results showed that the main metabolic pathways of diphenidol in the human body include hydroxylation, oxidation, dehydration, N-dealkylation, methylation, and conjugation with glucuronic acid. This study preliminarily clarified the metabolic pathways and main metabolites of diphenidol. For the development of new methods for the identification of diphenidol consumption, we recommend using M2-2 as a marker of diphenidol entering the body. The results of this study provide a theoretical basis for the pharmacokinetics and forensic scientific research of diphenidol.

Application of a Validated UPLC-MS-MS Method for the Determination of Diphenidol in Biological Samples in 15 Authentic Lethal Cases.

Diphenidol (DPN) is a nonphenothiazinic antivertigo and antiemetic drug that has been widely used in clinical practice in China because of its good antivertigo curative effect, minimal side effects and high safety. In recent years, there have been some cases of sporadic suicide and accidental poisoning related to DPN. Hence, a validated method for the determination of DPN in biological samples by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) was developed. The method is characterized by the use of a simple, fast and inexpensive liquid-liquid extraction (LLE) for sample preparation, a rapid run time (5 min) and a low required sample volume (0.1 mL or 0.1 g). The lower limits of quantitation (LLOQs) were 0.05 ng/mL and 0.3 ng/g for blood and liver tissue, respectively. The method was shown to be linear over a concentration range of 0.05-200 ng/mL (blood) and 0.3-400 ng/g (liver). The accuracy was in the range of 92.77-112.75%. The relative standard deviations of the intraday and interday imprecisions were in the range of 3.22% to 12.17%, and the recoveries were in the range of 58.75-95.27%. Furthermore, the method was successfully applied to the detection and quantification of DPN in 15 real forensic cases. The postmortem concentration range of heart blood was 0.87-99 µg/mL.

Detection of a New Tert-Leucinate Synthetic Cannabinoid 5F-MDMB-PICA and Its Metabolites in Human Hair: Application to Authentic Cases.

Methyl 2 -[ [ 1- (5- fluoropentyl) indole - 3- carbonyl] amino] -3, 3- dimethyl - butanoate (5F-MDMB-PICA) is a new synthetic cannabinoid characterized by valinate or tert-leucinate moieties. In recent years, 5F-MDMB-PICA has been abused in the form of "spice-like" herbal incenses or electronic cigarette oil. A UHPLC-MS/MS method was developed to detect 5F-MDMB-PICA and its metabolites in human hair. Approximately 20 mg of hair was weighed and pulverized with methanol below 4°C. After ultrasonication, centrifugation and filtration, 200 µL of supernatant was placed into an autosampler vial and analyzed on a Waters Acquity UPLC HSS T3 column (100 mm × 2.1 mm, 1.8 µm particle size) using an acetonitrile-20 mmol/L ammonium acetate (0.1% formic acid, 5% acetonitrile) gradient with a run time of 8 min. The limit of detection (LOD) ranged from 0.5 to 5 pg/mg, and the lower limit of quantitation (LLOQ) ranged from 1 to 5 pg/mg. The method was shown to be linear over a concentration range of 1-200 pg/mg. The linear correlation (R 2) of the calibration curves for all analytes was >0.999. The accuracy varied from 95.4 to 107.4%, while the intra- and inter-day precision RSD values were 0.7-10.6% and 1.7-12.2%, respectively. Recoveries were within the range of 61.1-93.3%, and matrix effects were in the range of 19.1-102.6%. The validated method was successfully applied to the identification and quantification of 5F-MDMB-PICA and its metabolites in hair from authentic forensic cases.

Simultaneous determination of 11 illicit drugs and metabolites in wastewater by UPLC-MS/MS.

Assessing collective drug consumption based on the concentrations of illicit drugs and their metabolites in wastewater is a new technology. Currently, this technology is receiving attention in China, and methods for multiple illicit drug detection in wastewater are urgently needed. In our study, a method with a short runtime (7 min), a small solid-phase extraction (SPE) loading volume (50 mL) and high sensitivity (lower limits of quantitation (LLOQs) ranged from 0.2 to 5 ng/L) was developed for the simultaneous determination of amphetamines, ketamine, opiates, cocaine and their metabolites in wastewater. Samples were enriched by SPE on a mixed-mode sorbent (Oasis MCX) and analyzed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The limits of detection (LODs) ranged from 0.1 to 2 ng/L, and the LLOQs varied between 0.2 and 5 ng/L. Moreover, the method developed was applied to real wastewater samples collected from 15 different wastewater treatment plants (WWTPs). In the results, the most abundant compounds were morphine (1.8-46.6 ng/L) and codeine (3.7-24.9 ng/L), which were detected in 13 WWTPs. After successful optimization of the UPLC-MS/MS conditions and sample loading pH, the method developed is able to meet the needs of common illicit drug monitoring and high-throughput analysis requirements.

UHPLC-MS/MS method for simultaneously detecting 16 tryptamines and their metabolites in human hair and applications to real forensics cases.

Tryptamines are hallucinogenic substances many of which have appeared recently as novel psychoactive substances (NPS). Herein, we describe the establishment of a rapid UHPLC-MS/MS quantitative method for the targeted screening of 16 tryptamines of abuse in hair. Twenty milligram pieces of hair were pulverized below 4 °C in 0.5 mL of deionized water containing 0.1% formic acid and an internal standard (2 ng/mL psilocin-d10 and psilocybin-d4). After subsequent centrifugation, 5 µL of the supernatant was injected into a LC-MS/MS system fitted with a Waters Acquity UPLC HSS T3 column (100 mm × 2.1 mm, 1.8 µm). The column was gradient eluted at 0.3 mL/min with mobile phases composed of 20 mmol/L ammonium acetate, 5% acetonitrile, and 0.1% formic acid in water (solvent A) and acetonitrile (solvent B). Limits of detection ranged between 0.1 and 20 pg/mg, with limits of quantitation ranging from 3 to 50 pg/mg. The calibration curves for all analytes were linear (r > 0.992). Accuracies varied between 91% and 114%, with intraday precision RSDs < 14% and interday precision RSDs of between 1.3% and 14%. The recoveries of all tryptamines were in the 85-115% range, with the matrix effect ranging from 95% to 112%. The validated method was successfully used to analyse 191 hair samples from suspected tryptamine users, 77 of which were 5-MeO-DiPT-positive, while the 16 tryptamines and their metabolites were not detected in the remaining 114 hair samples. 5-MeO-DiPT and its 5-MeO-NiPT, 5-OH-DiPT, and 4-OH-DiPT metabolites were concurrently detected in 34 hair samples. 5-MeO-DiPT, as the parent drug, was the parent substance found in the hair samples.

Determination of 37 fentanyl analogues and novel synthetic opioids in hair by UHPLC-MS/MS and its application to authentic cases.

The recent emergence of new fentanyl analogues and synthetic opioids on the drug market poses a global public health threat. However, these compounds cannot typically be identified using existing analytical methods. In this study, we aimed to develop and validate a rapid and sensitive method based on ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for the simultaneous determination of 37 fentanyl analogues and novel synthetic opioids in hair samples. Hair samples (20 mg) were extracted by cryogenic grinding in an extraction medium of methanol, acetonitrile, and 2 mmol/L ammonium acetate (pH 5.3). Following centrifugation of the samples, the analytes were separated using a WATERS Acquity UPLC HSS T3 column. The limits of detection (LODs) and limits of quantification (LOQs) ranged from 0.5 to 2.5 pg/mg and from 2 to 5 pg/mg, respectively. The intraday and interday precisions were within 13.32% at LOQ, low, medium, and high levels. The accuracies were within the range of 85.63-116.1%. The extraction recoveries were in the range of 89.42-119.68%, and the matrix effects were within the range of 44.81-119.77%. Furthermore, the method was successfully applied to the detection and quantification of fentanyl and sufentanil in hair samples from two authentic cases. Thus, this method has great potential for detecting fentanyl analogues and novel synthetic opioids in forensic work.

A Retrospective of Prevalence of Drugs of Abuse by Hair Analysis in Shanghai using LC-MS-MS.

This study presents a retrospective analysis of the prevalence of drug abuse in Shanghai by hair analysis. Files and toxicology analysis results of a total of 5,610 cases requesting for hair analysis of abused drugs at the Academy of Forensic Science (AFS) in Shanghai over 12 months between August 2018 and July 2019 were reviewed. All cases of drug abuse identified by hair analysis were from the public security organs in Shanghai, China. Hair samples were analyzed for drugs of abuse and related metabolites, mainly including amphetamine (AMP), methamphetamine (MA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), tetrahydrocannabinol (THC), ketamine (K), norketamine (NK), cocaine (COC), benzoylecgonine, morphine, 6-acetylmorphine, flunitrazepam, and 5-methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT), using liquid chromatography-tandem mass spectrometry (LC-MS-MS). Among the 5,610 cases, 1,713 (30.5%) were positive for drugs of abuse, with amphetamine-type stimulants (ATS) (57%), including amphetamines (AMP and MA) (48%), MDMA and MDA (9%), being the most frequently detected drugs, followed by THC (14%), COC (8%), 5-MeO-DIPT (8%), and K (7%). The majority (75%) of positive hair samples were from male subjects. Overall, 77% of abusers were younger than 44 years old. The proportion of female subjects (22.3%) under 24 years was larger than that of male subjects (7.8%). There were 132 cases (7.7%) in which more than one type of drug was detected among 1,713 drug-positive cases. The most common combination was MDMA and K. The present study characterizes the current toxicological profile of drug abuse cases and provides a scientific basis for drug abuse prevention. Moreover, the hair concentration distributions of the commonly abused drugs in positive cases have been reported.

Segmental Analysis of R/S-Methamphetamine and R/S-Amphetamine in Abusers' Head Hair.

In this study, the relationships between the concentrations of R/S-methamphetamine (MA) and its metabolite R/S-amphetamine (AP), the AP/MA ratio in hair samples, and MA dependence were investigated by performing segmental hair analysis in MA users. Authentic hair samples collected from 10 chronic MA abusers were cut into 1-cm sections (a total of 120 segments). The concentrations of MA and AM enantiomers were quantitatively measured by the LC-MS-MS method. The S-MA concentrations ranged from 1.17 to 256.41 ng/mg and the S-AP concentrations ranged from 0.11 to 23.31 ng/mg in the 120 segments. S-MA and S-AP were the most common analytes identified in hair; no R-MA or R-AP was found. The S-AP/S-MA ratios ranged from 0.03 to 0.32, indicating that the subjects primarily consumed S-MA rather than R-MA or AP. The S-AP/S-MA ratios in the long hair of all chronic MA abusers showed some variation, but there was an overall trend of gradual increase from the distal to the proximal end. This trend was independent of the drug concentrations. Therefore, we could conclude that the AP/MA ratios increased with the duration of MA abuse, and a higher AP/MA ratio suggested high MA dependence. There was no chiral conversion of MA or AP in the hair matrix. The segmental hair analysis showed that all subjects continuously used S-MA, and some users showed an increase in drug dose or the frequency of use.

Application of a validated UHPLC-MS/MS method for 28 fentanyl-analogue and novel synthetic opioids in whole blood in authentic forensic cases.

The abuse of fentanyl and its analogues, which are potent, short-acting, synthetic narcotic analgesics, has become a major issue. Many cases containing fentanyl-analogue and novel synthetic opioids have also been reported. Hence, we report the determination of fentanyl, fentanyl-analogue and novel synthetic opioids in whole blood by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method is characterized by the use of a simple, fast and inexpensive liquid-liquid extraction (LLE) for sample preparation, a rapid run time (8 min) and a low required volume of whole blood (100 µl). The limits of detection (LODs) ranged from 0.005 to 0.03 ng/ml, and the lower limits of quantitation (LLOQs) ranged from 0.05 to 0.2 ng/ml. The method was shown to be liner over a concentration range of 0.2-40 ng/ml for fentanyl, norfentanyl and norcarfentanil and 0.05-40 ng/ml for all other target analytes. Recoveries were within the range of 72.09%-103.22%, and the matrix effects were in the 67.95%-113.32% range. Moreover, the method was applied to the detection and quantification of fentanyl and its analogues in whole blood from real forensic cases. This methodology has great potential for use in the determination of fentanyl and its analogues in forensic cases.

An LC-MS/MS method for the simultaneous determination of 12 psychotropic drugs and metabolites in hair: Identification of acute quetiapine poisoning using hair root.

A rapid, sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination and quantification of 12 psychotropic drugs and metabolites in hair was developed and validated. After freeze grinding with methanol, the supernatant was determined by LC-MS/MS using an Allure PFPPropyl column (100 × 2.1 mm, 5 µm) with a gradient elution of acetonitrile and 10 mmol/L ammonium acetate with 0.1% formic acid, and in the subsequent analysis using multiple reaction monitoring (MRM) mode, two ion transitions were monitored for each analyte. The limits of detection ranged from 0.002 to 0.05 ng/mg, and the limits of quantitation were in the range of 0.005-0.1 ng/mg. Good linearity (r > 0.995) was observed for all analytes over the linear range. Acceptable intraday and interday precision (RSD ≤ 20%) and accuracy (85.3%-112.9%) were achieved. This method of detection was applied to the analysis of guinea pig hair roots after a single dose of quetiapine. Quetiapine and 7-hydroxyquetiapine were both detected in guinea pig hair roots from 5 min post administration. The concentration of quetiapine (10.3-1733.8 ng/mg) was much higher than that of 7-hydroxyquetiapine (0.1-40.6 ng/mg) in the hair roots of guinea pigs, and higher concentrations of quetiapine and 7-hydroxyquetiapine occurred in black hair root than in that of white and brown. The animal experiment demonstrated that hair roots may be a good specimen for proving acute quetiapine poisoning when other biological matrices are not available.

Simultaneous Determination of Selegiline, Desmethylselegiline, R/S-methamphetamine, and R/S-amphetamine on Dried Urine Spots by LC/MS/MS: Application to a Pharmacokinetic Study in Urine.

Objective: Chiral analysis is a crucial method to differentiate selegiline intake from drug abuse. A dried urine spot (DUS) analytical method based on spotting urine samples (10 µL) onto dried spot collection cards, and followed by air-drying and extraction, was developed and validated for the determination of selegiline, desmethylselegiline, R/S-methamphetamine, and R/S-amphetamine. Methods: Methanol (0.5 mL) was found to be the ideal extraction solvent for target extraction from DUSs under orbital-horizontal stirring on a lateral shaker at 1,450 rpm for 30 min. Determinations were performed by direct electrospray ionization tandem mass spectrometry (ESI-MS/MS) under positive electrospray ionization conditions using multiple reaction monitoring mode. The chromatographic system consisted of a ChirobioticTM V2 column (2.1 × 250 mm, 5 µm) and a mobile phase of methanol containing 0.1% (v/v) glacial acetic acid and 0.02% (v/v) ammonium hydroxide. Results and conclusions: The calibration curves were linear from 50 to 5,000 ng/mL, with r > 0.995 for all analytes, imprecisions ≤ 15% and accuracies between -11.4 and 11.7%. Extraction recoveries ranged from 48.6 to 105.4% with coefficients of variation (CV) ≤ 13.7%, and matrix effects ranged from 45.4 to 104.1% with CV ≤ 10.3%. The lower limit of quantification was 50 ng/mL for each analyte. The present method is simple, rapid (accomplished in 12 min), sensitive, and validated by a pharmacokinetic study in human urine collected after a single oral administration of SG.

Pharmacokinetics of selegiline, R-methamphetamine, R-amphetamine, and desmethylselegiline in oral fluid after a single oral administration of selegiline.

BACKGROUND: Chiral analysis is a crucial way to differentiate selegiline (SG) intake from drug abuse. Oral fluid (OF) has been successfully used as an alternative matrix for blood testing in several pharmacokinetic studies. OBJECTIVE: The aim of this study is to describe the pharmacokinetics of SG and its main metabolites in OF after a single oral administration of SG which is meaningful for results interpretation in forensic analysis. METHODS: Ten milligrams of SG were orally administered to 8 volunteers, and OF samples were collected for up to 96 hours by having participants spit into polypropylene tubes without stimulation. These samples were submitted to liquid-liquid extraction before analysis by liquid chromatography-tandem mass spectrometry operating in positive ion multiple-reaction monitoring mode. RESULTS AND CONCLUSIONS: After oral administration, each analyte could be detected in OF specimens from all volunteers with an initial detection time of 0.50 hours. The Cmax values of SG, R-MA, R-AM and DM-SG were 50.93-992.67 ng/mL, 29.78-653.64 ng/mL, 8.22-150.15 ng/mL, and 4.34-16.25 ng/mL, respectively, at 0.5 hours, 1-11 hours, 1.5-11 hours, and 0.5-6 hours post dose. The times when the compounds were last determined in OF were 5-24 hours for SG, 52-96 hours for R-MA, 31-96 hours for R-AM, and 13-31 hours for DM-SG after oral administration. There is a period of time in OF in which only MA and AM are present without SG and DM-SG after a single dose of SG. The pharmacokinetic data could provide supplementary interpretation for OF tests in forensic science and drug treatment programs.