Systematic retrospective processing of previously analysed biological samples has been proven to be a valuable tool in the search for new drugs (e.g. new psychoactive substances (NPS)) and for quality assessment in clinical and forensic toxicology. In a previous study, we developed a strategy for retrospective data-analysis using a personalized library of synthetic cannabinoids, designer benzodiazepines and synthetic opioids obtained from the crowdsourced database HighResNPS (https://highresnps.com). In this study, the same strategy was employed for the compounds within the groups of NPS that were not previously included such as synthetic cathinones, phenethylamines, aminoindanes, arylalkylamines, piperazine derivates, piperidines, pyrrolidines, indolalkylamines and arylcyclohexylamines. Synthetic opioids and designer benzodiazepines, which were not part of the previous study, were also included. To enhance the effectiveness of the retrospective analysis, a predicted retention time was included for all entries. Data files from the analysis of 2186 forensic post mortem samples with an Agilent Technologies 6540 ultra-high pressure liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) performed in the laboratory from January 2014 to December 2021 were retrospectively processed with the up-to-date library. Tentative findings were classified in two groups: The findings where MS/MS data was acquired for library match (category 1) and the less certain findings where such data lacked (category 2). Five compounds of category 1 (three synthetic cathinones and two indolalkylamines) were identified in 12 samples. Only one of the findings, 4-MEAPP (4-methyl- alpha-ethylaminopentiophenone), was deemed plausible after reviewing case information. As many as 501 presumably positive category 2 findings were detected. Using the predicted retention time as an additional criterion the number was significantly reduced but still too high for a manual review. This work has demonstrated that the strategy developed in the previous study can be applied to other NPS groups. However, it is important to note the limitations such a method may have in detecting compounds at very low concentrations.

A highly sensitive and accurate electrospray liquid chromatography tandem-mass spectrometry (ESI-LC–MS/MS) method for determination of testosterone in human serum and saliva was developed and validated. Accurate quantification of testosterone in human matrices is essential in diagnosis and management of androgen status in men, women and children, and in forensic investigations of suspected abuse of anabolic androgenic steroids. Chromatography was performed on an HSS-T3 C18 column with a total run-time of 5.5 min. The tandem mass spectrometry was operated in positive electrospray ionization mode with multiple reaction monitoring. Serum and saliva samples of 200 μL, were prepared by solid-phase extraction using a 96-well plate following precipitation with 200 μL methanol. 13C labeled testosterone was used as internal standard for quantification. The standard curve was linear within the range of 4−1000 pg/mL and the limit of quantification of both serum and salivary testosterone was 4 pg/mL. Accuracy were 99–101 % and 93–95 % with between-run imprecision in serum and saliva, respectively, and inter- and intra-assay coefficients of variation were less than 9.2 %. The method proved to be applicable for determination of testosterone over a wide range of concentrations in serum and saliva samples from clinical patients with various androgen disorders, healthy male and female adults as well as from forensic cases.

At the Swedish national forensic toxicology laboratory, a measured testosterone/epitestosterone (T/E) ratio?≥?12 together with testosterone/luteinizing hormone (T/LH) in urine?>?400?nmol/IU is considered as a proof of exogenous testosterone administration. However, according to the rules of the World Anti-Doping Agency (WADA), samples with T/E ratio?>?4 are considered suspicious and shall be further analysed by gas chromatography?combustion?isotope ratio mass spectrometry (GC-C-IRMS) to confirm the origin of testosterone and its metabolites. The aim of this study was to investigate the possibility of false negative results and to estimate the frequency of negative results using the current criteria for detection of abuse of testosterone in forensic investigations. Urine and serum samples were collected by the police at suspected infringement of the doping law in Sweden. Fifty-eight male subjects were included in the study. Urinary testosterone was determined by gas chromatography?mass spectrometry (GC?MS), serum testosterone and LH?by immunoassay. The origin of testosterone and its metabolites was confirmed by means of GC-C-IRMS. Twenty-six of the 57 analysed subjects tested positive for exogenous testosterone using the criteria T/E?≥?12 combined with T/LH?>?400?nmol/IU. The IRMS analyses confirmed 47 positives; thus, 21 were considered false negatives. Negative predictive value was 32% (95% confidence interval [CI]: 16%?50%) and sensitivity 55%. No false positive subjects were found. The number of false negative cases using the current criteria for the detection of testosterone abuse and hence the low sensitivity indicates a need to discuss introduction of new strategies in forensic doping investigations.

New psychoactive substances are emerging on the illegal drug market. Synthetic opioids including fentanyl analogues are of special concern due to their high potency. This indicates the possibility of low drug concentrations in vivo and calls for sensitive analytical methods and identification of the most appropriate analytical targets. In this study the in vitro metabolism of ortho-, meta- and para-fluorofentanyl, three fluorinated derivatives of fentanyl, has been investigated using human hepatocytes and compared to the results from an authentic human urine sample. Based on knowledge on the metabolism of similar fentanyl analogues N-dealkylation and hydroxylation was hypothesized to be the most central pathways. The three fluorofentanyl isomers were incubated with pooled human hepatocytes at 1, 3 and 5 h. Liquid chromatography quadrupole time of flight mass spectrometry operating in data-dependent mode was used to analyse the hepatocyte samples, as well as the hydrolysed and non-hydrolysed authentic urine sample. Data were analysed by a targeted approach with a database of potential metabolites. The major metabolite formed in vitro was the N-dealkylation product norfluorofentanyl. In addition various hydroxylated metabolites, a N-oxide, dihydrodiol metabolites and a hydroxymethoxy metabolite were found. In total, 14 different metabolites were identified for each fluorofentanyl isomer. In the authentic urine sample, three metabolites were detected in addition to the ortho-fluorofentanyl parent compound, with hydroxymethoxy metabolite having the highest abundance followed by norfluorofentanyl and a metabolite hydroxylated on the ethylphenyl ring. This in vitro study showed that the metabolic pattern for ortho-, meta-, and para-fluorofentanyl was close to those previously reported for other fentanyl analogues. We suggest that the hydroxymethoxy metabolite and the metabolite hydroxylated on the ethylphenyl ring should be the metabolites primarily investigated in further studies to determine the most appropriate marker for intake of fluorofentanyl derivatives in urine drug screening for human subjects.

The introduction of new psychoactive substances (NPS) on the illicit drug market has led to major challenges for the analytical laboratories. Keeping screening methods up to date with all relevant drugs is hard to achieve and the risk of missing important findings in biological samples is a matter of concern. Aiming for an extended retrospective data analysis, diagnostic fragment ions from synthetic cannabinoids (n = 251), synthetic opioids (n = 88) and designer benzodiazepines (n = 26) not included in our original analytical method were obtained from the crowdsourced database HighResNPS.com and converted to a personalized library in a format compatible with the analytical instrumentation. Data files from the analysis of 1314 forensic post mortem samples with an Agilent 6540 ultra high pressure liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) performed in our laboratory from January 2014 to December 2018 were retrieved and retrospectively processed with the new personalized library. Potentially positive findings were grouped in two: The most confident findings contained MS/MS data for library match (category 1) whereas the less confident findings lacked such data (category 2). Five new category 1 findings were identified: Flubromazepam in two data files from 2015 and 2016, respectively, phenibut (4-amino-3-phenylbutyric acid) in one data file from 2015, fluorofentanyl in one data file from 2016 and cyclopropylfentanyl in one data file from 2018. Retention time matches with reference standards further strengthened these findings. A list of 35 presumably positive category 2 findings was generated. Of these, only one finding of phenibut was considered plausible after checking retention times and signal-to-noise ratios. This study shows that new compounds can be detected retrospectively in data files from QTOF-MS using an updated library containing diagnostic fragment ions. Automatic screening procedures can be useful, but a manual re-evaluation of positive findings will always be necessary. (C) 2020 The Author(s). Published by Elsevier B.V.

Synthetic cannabinoids are one of the most significant groups within the category new psychoactive substances (NPS) and in recent years new compounds have continuously been introduced to the market of recreational drugs. A sensitive and quantitative screening method in urine with metabolites of frequently seized compounds in Norway (AB-FUBINACA, AB-PINACA, AB-CHMINACA, AM-2201, AKB48, 5F-AKB48, BB-22, JWH-018, JWH-073, JWH-081, JWH-122, JWH-203, JWH-250, PB-22, 5F-PB-22, RCS-4, THJ-2201, and UR-144) using ultra-high pressure liquid chromatography-quadrupole time of flight-mass spectrometry (UHPLC-QTOF-MS) has been developed. The samples were treated with ss-glucuronidase prior to extraction and solid-phase extraction was used. Liquid handling was automated using a robot. Chromatographic separation was achieved using a C18-column and a gradient of water and acetonitrile, both with 0.1% formic acid. Each sample was initially screened for identification and quantification followed by a second injection for confirmation. The concentrations by which the compounds could be confirmed varied between 0.1 and 12 ng/mL. Overall the validation showed that the method fulfilled the set criteria and requirements for matrix effect, extraction recovery, linearity, precision, accuracy, specificity, and stability. One thousand urine samples from subjects in drug withdrawal programs were analyzed using the presented method. The metabolite AB-FUBINACA M3, hydroxylated metabolite of 5F-AKB48, hydroxylated metabolite of AKB48, AKB48 N-pentanoic acid, 5F-PB-22 3-carboxyindole, BB-22 3-carboxyindole, JWH-018 N-(5-hydroxypentyl), JWH-018 N-pentanoic acid, and JWH-073 N-butanoic acid were quantified and confirmed in 2.3% of the samples. The method was proven to be sensitive, selective and robust for routine use for the investigated metabolites.

In Sweden, information on drug use during pregnancy is obtained through an interview and recorded in a standardized medical record at every visit to the antenatal care clinic throughout the pregnancy. Antenatal, delivery, and neonatal records constitute the basis for the Swedish Medical Birth Register (MBR). The purpose of this exploratory study was to investigate the reliability of reported drug use by simultaneous screening for drug substances in the blood stream of the pregnant woman and thereby validate self-reported data in the MBR. Plasma samples from 200 women were obtained at gestational weeks 10-12 and 25 and screened for drugs by using ultra-high performance liquid chromatography with time of flight mass spectrometry (UHPLC-TOF-MS). The results from the analysis were then compared to medical records. At the first sampling occasion, the drugs found by screening had been reported by 86% of the women and on the second sampling, 85.5%. Missed reported information was clearly associated with drugs for occasional use. The most common drugs in plasma taken in early and mid-pregnancy were meclizine and paracetamol. Two types of continuously used drugs, selective serotonin reuptake inhibitors and propranolol, were used. All women using them reported it and the drug screening revealed a 100% coherence. This study shows good coherence between reported drug intake and the drugs found in plasma samples, which in turn positively validates the MBR.

Tramadol is a complex drug, being metabolized by polymorphic enzymes and administered as a racemate with the (+)- and (-)-enantiomers of the parent compound and metabolites showing different pharmacological effects. The study aimed to simultaneously determine the enantiomer concentrations of tramadol, O-desmethyltramadol, N-desmethyltramadol, and N,O-didesmethyltramadol following a single dose, and elucidate if enantioselective pharmacokinetics is associated with the time following drug intake and if interindividual differences may be genetically explained. Nineteen healthy volunteers were orally administered either 50 or 100 mg tramadol, whereupon blood samples were drawn at 17 occasions. Enantiomer concentrations in whole blood were measured by LC-MS/MS and the CYP2D6,CYP2B6 and CYP3A4 genotype were determined, using the xTAG CYP2D6 Kit, pyrosequencing and real-time PCR, respectively. A positive correlation between the (+)/(-)-enantiomer ratio and time following drug administration was shown for all four enantiomer pairs. The largest increase in enantiomer ratio was observed for N-desmethyltramadol in CYP2D6 extensive and intermediate metabolizers, rising from about two to almost seven during 24 hours following drug intake. CYP2D6 poor metabolizers showed metabolic profiles markedly different from the ones of intermediate and extensive metabolizers, with large area under the concentration curves (AUCs) of the N-desmethyltramadol enantiomers and low corresponding values of the O-desmethyltramadol and N,O-didesmethyltramadol enantiomers, especially of the (+)-enantiomers. Homozygosity of CYP2B6 *5 and *6 indicated a reduced enzyme function, although further studies are required to confirm it. In conclusion, the increase in enantiomer ratios over time might possibly be used to distinguish a recent tramadol intake from a past one. It also implies that, even though (+)-O-desmethyltramadol is regarded the enantiomer most potent in causing adverse effects, one should not investigate the (+)/(-)-enantiomer ratio of O-desmethyltramadol in relation to side effects without consideration for the time that has passed since drug intake.

The use of hyphenated analytical techniques in forensic drug screening enables simultaneous identification of a wide range of different compounds. However, the appearance of drug seizures containing new substances, mainly new psychoactive substances (NPS), is steadily increasing. These new and other already known substances often possess structural similarities and consequently they exhibit spectral data with slight differences. This situation has made the criteria that ensure indubitable identification of compounds increasingly important. In this work, 6 new synthetic cathinones that have not yet appeared in any Swedish drug seizures were synthesized. Their chemical structures were similar to those of already known cathinone analogs of which 42 were also included in the study. Hence, a total of 48 synthetic cathinones making up sets of homologous and regioisomeric compounds were used to challenge the capabilities of various analytical techniques commonly applied in forensic drug screening, ie, gas chromatography-mass spectrometry (GC-MS), gas chromatography-Fourier transform infrared spectroscopy (GC-FTIR), nuclear magnetic resonance (NMR), and liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Special attention was paid to the capabilities of GC-MS and GC-FTIR to distinguish between the synthetic cathinones and the results showed that neither GC-MS nor GC-FTIR alone can successfully differentiate between all synthetic cathinones. However, the 2 techniques proved to be complementary and their combined use is therefore beneficial. For example, the structural homologs were better differentiated by GC-MS, while GC-FTIR performed better for the regioisomers. Further, new spectroscopic data of the synthesized cathinone analogs is hereby presented for the forensic community. The synthetic work also showed that cathinone reference compounds can be produced in few reaction steps.

AKB-48 belongs to the family of synthetic cannabinoids. It has strong binding affinity to CBI receptor and is psychoactive. It is banned in many countries including USA, Japan, Germany, New Zealand, Singapore and China etc. But the difficulty in detecting the parent compound in urine samples highlights the importance of studies of its metabolites. Here we report the synthesis of 19 potential metabolites of AKB-48, among which, compounds 2, 9, 10, 30 and 31, together with the commercially available substance 5 were identified as metabolites of AKB-48 by comparison with one authentic human urine sample and human liver microsomal data. Compounds 10 and 30 could be of use as biomarkers in detecting AKB-48 in human urine samples. (C) 2018 Elsevier Ltd. All rights reserved.

25C-NBOMe and 25I-NBOMe are potent hallucinogenic drugs that recently emerged as new psychoactive substances. To date, a few metabolism studies were conducted for 25I-NBOMe, whereas 25C-NBOMe metabolism data are scarce. Therefore, we investigated the metabolic profile of these compounds in human hepatocytes, an in vivo mouse model and authentic human urine samples from forensic cases. Cryopreserved human hepatocytes were incubated for 3 h with 10 μM 25C-NBOMe and 25I-NBOMe; samples were analyzed by liquid chromatography high-resolution mass spectrometry (LC-HRMS) on an Accucore C18 column with a Thermo QExactive; data analysis was performed with Compound Discoverer software (Thermo Scientific). Mice were administered 1.0 mg drug/kg body weight intraperitoneally, urine was collected for 24 h and analyzed (with or without hydrolysis) by LC-HRMS on an Acquity HSS T3 column with an Agilent 6550 QTOF; data were analyzed manually and with WebMetabase software (Molecular Discovery). Human urine samples were analyzed similarly. In vitro and in vivo results matched well. 25C-NBOMe and 25I-NBOMe were predominantly metabolized by O-demethylation, followed by O-di-demethylation and hydroxylation. All methoxy groups could be demethylated; hydroxylation preferably occurred at the NBOMe ring. Phase I metabolites were extensively conjugated in human urine with glucuronic acid and sulfate. Based on these data and a comparison with synthesized reference standards for potential metabolites, specific and abundant 25C-NBOMe urine targets are 5'-desmethyl 25C-NBOMe, 25C-NBOMe and 5-hydroxy 25C-NBOMe, and for 25I-NBOMe 2' and 5'-desmethyl 25I-NBOMe and hydroxy 25I-NBOMe. These data will help clinical and forensic laboratories to develop analytical methods and to interpret results. Copyright © 2016 John Wiley & Sons, Ltd.

Meclonazepam is a benzodiazepine patented in 1977 to treat parasitic worms, which recently appeared as a designer benzodiazepine and drug of abuse. The aim of this study was to identify metabolites suitable as biomarkers of drug intake in urine using high-resolution mass spectrometry, authentic urine samples, and different model systems including human liver microsomes, cryopreserved hepatocytes, and a mice model. The main metabolites of meclonazepam found in human urine were amino-meclonazepam and acetamido-meclonazepam; also, minor peaks for meclonazepam were observed in three of four urine samples. These observations are consistent with meclonazepam having a metabolism similar to that of other nitro containing benzodiazepines such as clonazepam, flunitrazepam, and nitrazepam. Both metabolites were produced by the hepatocytes and in the mice model, but the human liver microsomes were only capable of producing minor amounts of the amino metabolite. However, under nitrogen, the amount of amino-meclonazepam produced increased 140 times. This study comprehensively elucidated meclonazepam metabolism and also illustrates that careful selection of in vitro model systems for drug metabolism is needed, always taking into account the expected metabolism of the tested drug.

BACKGROUND: Methylphenidate (MPH), along with behavioral and psychosocial interventions, is the first-line medication to treat attention-deficit hyperactivity disorder (ADHD) in Sweden. The dose of MPH for good symptom control differs between patients. However, studies of MPH concentration measurement in ADHD treatment are limited.

OBJECTIVE: To describe blood and oral fluid (OF) concentrations of MPH after administration of medication in patients with well-adjusted MPH treatment for ADHD, and to identify the most suitable matrix for accurate MPH concentration during treatment.

METHODS: Patients were recruited from Child and Adolescent Psychiatry (CAP), General Psychiatry (GP), and the Department of Dependency (DD). Blood and OF samples were collected in the morning before MPH administration as well as 1 and 6 h after administration of the prescribed morning dose of MPH.

RESULTS: Fifty-nine patients aged between 9 and 69 years, 76 % males. The daily dose of MPH varied from 18 to 180 mg, but the median daily dose per body weight was similar, approximately 1.0 mg/kg body weight. The median MPH concentration in blood 1 and 6 h after the morning dose was 5.4 and 9.3 ng/mL, respectively. Highly variable OF-to-blood ratios for MPH were found at all time points for all three groups.

CONCLUSIONS: Weight is a reliable clinical parameter for optimal dose titration. Otherwise, MPH blood concentration might be used for individual dose optimization and for monitoring of the prescribed dose. Relying only on the outcome in OF cannot be recommended for evaluation of accurate MPH concentrations for treatment monitoring.

Studies on the metabolism of bioactive substances containing the adamantyl moiety have shown that hydroxylation is likely to occur at a tertiary carbon of adamantane. Herein, we report the synthesis and identification of one major metabolite of AKB-48, a new illicit psychoactive substance with a hydroxyl group at a secondary carbon of the adamantyl ring. (C) 2017 Elsevier Ltd. All rights reserved.

Synthetic routes have been developed for synthesis of potential metabolites of 25C-NBOMe and 25I-NBOMe. Nine potential metabolites have been synthesized, among which compounds 8 and 20a could be used as metabolite biomarkers of 25C-NBOMe and 20b of 25I-NBOMe in urinary detection at forensic laboratories to prove intake. (C) 2017 Elsevier Ltd. All rights reserved.

Synthetic cannabinoids are a group of psychoactive drugs presently widespread among drug users in Europe. Analytical methods to measure these compounds in urine are in demand as urine is a preferred matrix for drug testing. For most synthetic cannabinoids, the parent compounds are rarely detected in urine. Therefore urinary metabolites are needed as markers of drug intake. AB-FUBINACA was one of the top three synthetic cannabinoids most frequently found in seizures and toxicological drug screening in Sweden (2013-2014). Drug abuse is also reported from several other countries such as the USA and Japan. In this study, 28 authentic case samples were used to identify urinary markers of AB-FUBINACA intake using liquid chromatography quadrupole tandem time of flight mass spectrometry and human liver microsomes. Three metabolites suitable as markers of drug intake were identified and at least two of them were detected in all but one case. In total, 15 urinary metabolites of AB-FUBINACA were reported, including hydrolxylations on the indazole ring and the amino-oxobutane moiety, dealkylations and hydrolysis of the primary amide. No modifications on the fluorobenzyl side-chain were observed. The parent compound was detected in 54% of the case samples. Also, after three hours of incubation with human liver microsomes, 77% of the signal from the parent compound remained. Copyright © 2015 John Wiley & Sons, Ltd.

In this work, emergence patterns of synthetic cannabinoids were utilized in an attempt to predict those that may appear on the drug market in the future. Based on this information, two base structures of the synthetic cannabinoid analogues - (1H-indol-3-yl (2,2,3,3-tetramethylcyclopropyl) methanone and 1H-indol-3-yl(adamantan-1-yl)methanone) - together with three substituents butyl, 4-fluorobutyl and ethyl tetrahydropyran - were selected for synthesis. This resulted in a total of six synthetic cannabinoid analogues that to the authors knowledge have not yet appeared on the drug market. Spectroscopic data, including nuclearmagnetic resonance (NMR), mass spectrometry (MS), and Fourier transforminfrared (FTIR) spectroscopy (solid and gas phase), are presented for the synthesized analogues and some additional related cannabinoids. In this context, the suitability of the employed techniques for the identification of unknowns is discussed and the use of GC-FTIR as a secondary complementary technique to GC-MS is addressed. Examples of compounds that are difficult to differentiate by their mass spectra, but can be distinguished based upon their gas phase FTIR spectra are presented. Conversely, structural homologueswhere mass spectra aremore powerful than gas phase FTIR spectra for unambiguous assignments are also exemplified. This work further emphasizes that a combination of several techniques is the key to success in structural elucidations. Copyright (C) 2015 John Wiley amp; Sons, Ltd.

The analgesic drug tramadol and its metabolites are chiral compounds, with the (+)- and (-)-enantiomers showing different pharmacological and toxicological effects. This novel enantioselective method, based on LC-MS/MS in reversed phase mode, enabled measurement of the parent compound and its three main metabolites O-desmethyltramadol, N-desmethyltramadol and N,O-didesmethyltramadol simultaneously. Whole blood samples of 0.5g were fortified with internal standards (tramadol-(13)C-D3 and O-desmethyl-cis-tramadol-D6) and extracted under basic conditions (pH 11) by liquid-liquid extraction. Chromatography was performed on a chiral alpha-1-acid glycoprotein (AGP) column preceded by an AGP guard column. The mobile phase consisted of 0.8% acetonitrile and 99.2% ammonium acetate (20mM, pH 7.2). A post-column infusion with 0.05% formic acid in acetonitrile was used to enhance sensitivity. Quantitation as well as enantiomeric ratio measurements were covered by quality controls. Validation parameters for all eight enantiomers included selectivity (high), matrix effects (no ion suppression/enhancement), calibration model (linear, weight 1/X(2), in the range of 0.25-250ng/g), limit of quantitation (0.125-0.50ng/g), repeatability (2-6%) and intermediate precision (2-7%), accuracy (83-114%), dilution integrity (98-115%), carry over (not exceeding 0.07%) and stability (stable in blood and extract). The method was applied to blood samples from a healthy volunteer administrated a single 100mg dose and to a case sample concerning an impaired driver, which confirmed its applicability in human pharmacokinetic studies as well as in toxicological and forensic investigations.

The occurrence of structurally related synthetic cannabinoids makes the identification of unique markers of drug intake particularly challenging. The aim of this study was to identify unique and abundant metabolites of AKB-48 and 5F-AKB-48 for toxicological screening in urine. Investigations of authentic urine samples from forensic cases in combination with human liver microsome (HLM) experiments were used for identification of metabolites. HLM incubations of AKB-48 and 5F-AKB-48 along with 35 urine samples from authentic cases were analyzed with liquid chromatography quadrupole tandem time of flight mass spectrometry. Using HLMs 41 metabolites of AKB-48 and 37 metabolites of 5F-AKB-48 were identified, principally represented by hydroxylation but also ketone formation and dealkylation. Monohydroxylated metabolites were replaced by di- and trihydroxylated metabolites within 30 min. The metabolites from the HLM incubations accounted for on average 84% (range, 67-100) and 91% (range, 71-100) of the combined area in the case samples for AKB-48 and 5F-AKB-48, respectively. While defluorinated metabolites accounted for on average 74% of the combined area after a 5F-AKB-48 intake only a few identified metabolites were shared between AKB-48 and 5F-AKB-48, illustrating the need for a systematic approach to identify unique metabolites. HLMs in combination with case samples seem suitable for this purpose.

The objective of this study was to compare the performance of an immunoassay screening for synthetic cannabinoids with a newly developed confirmation method using liquid chromatography quadrupole time-of-flight mass spectrometry. The screening included metabolites from JWH-018, JWH-073, and AM-2201. The confirmation included metabolites from AM-2201, JWH-018, JWH-019, JWH-073, JWH-081, JWH-122, JWH-210, JWH-250, JWH-398, MAM-2201, RCS-4, and UR-144. The immunoassay was tested and found to have no cross-reactivity with UR-144 metabolites but considerable cross-reactivity with MAM-2201 and JWH-122 metabolites. Sensitivity and specificity for the immunoassay were evaluated with 87 authentic urine samples and found to be 87 % and 82 %, respectively. With a cutoff at 2 ng/ml, the confirmation showed 80 positive findings in 38 cases. The most common finding was JWH-122 5-OH-pentyl, followed by JWH-018 5-OH-pentyl. There were 9 findings of UR-144 metabolites and 3 of JWH-073 metabolites. In summary, the immunoassay performed well, presenting both high sensitivity and specificity for the synthetic cannabinoids present in the urine samples tested. The rapid exchange of one cannabinoid for another may pose problems for immunoassays as well as for confirmation methods. However, we consider time-of-flight mass spectrometry to be superior since new metabolites can be quickly included and identified.

A liquid chromatography/time-of-flight mass spectrometry (LC-TOF-MS) method for targeted toxicological screening in human postmortem blood samples from forensic autopsy cases has been developed, validated and compared with a previously used method using gas chromatography with nitrogen-phosphorus detection (GC-NPD). Separation was achieved within 12 min by high-resolution gradient chromatography. Ions were generated in positive and negative electrospray ionization mode and were detected in 2-GHz single mass spectrometry mode, m/z range 50-1,000. Before injection, 0.25 g blood was prepared by protein precipitation with 500 mu L of a mixture of acetonitrile and ethanol containing deuterated internal standards. An in-house database comprising 240 drugs and metabolites was built by analysing solutions from certified standards or other documented reference material available. Identification was based on scoring of retention time, accurate mass measurement and isotopic pattern. Validation was performed on spiked blood samples and authentic postmortem blood samples. The thresholds defined as minimum required performance levels were for most compounds in the range from 0.01 to 0.10 mu g/g. Typically, a mass error of less than 2 ppm and a precision of area measurements of less than 5 % coefficient of variation were achieved. Positive identification was confirmed at concentrations up to 500 mu g/g. Most compounds were determined in positive ionization mode, but for a limited number of compounds (fewer than 4 %) negative ionization was needed and a few early-eluted compounds could not be identified owing to substantial influence of interferences from the matrix and were thus not included in the screening. A robust and valid toxicological screening by LC-TOF-MS for postmortem blood samples, covering 50 % more compounds, and with higher precision and sensitivity than the previously used screening by GC-NPD was achieved.

A high-performance liquid chromatography method capable of measuring thiopurine mono-, di-, and triphosphates separately in red blood cells (RBCs) was developed. RBCs were isolated from whole blood using centrifugation. Proteins were precipitated using dichloromethane and methanol. The thioguanine nucleotides (TGNs) were derivatised using potassium permanganate before analysis. Analytes were separated by ion-pairing liquid chromatography using tetrabutylammonium ions and detected using UV absorption and fluorescence. The method was designed for use in clinical trials. Ten patient samples were analysed to demonstrate clinical application and to establish pilot ranges for all analytes. less thanbrgreater than less thanbrgreater thanThe method measured thioguanosine mono-(TGMP), di-(TGDP), and triphosphate (TGTP), as well as methylthioinosine mono- (meTIMP), di- (meTIDP) and triphosphate (meTITP) in RBCs collected from patients treated with thiopurine drugs (azathioprine, 6-mercaptopurine, and 6-thioguanine). less thanbrgreater than less thanbrgreater thanLOQ was 0.3, 3, 2, 30, 30 and 40 pmol/8 x 10(8) RBC, for TGMP, TGDP, TGTP, meTIMP, meTIDP and meTITP, respectively. Between-day precision were below 14% for all analytes at all concentrations and samples were stable at 4 degrees C for 8 h after sampling.

Venlafaxine (VEN) is an antidepressant drug mainly metabolized by the cytochrome P450 (CYP) enzyme CYP2D6 to the active metabolite O-desmethylvenlafaxine (ODV). VEN is also metabolized to N-desmetylvenlafaxine (NDV) via CYP3A4. ODV and NDV are further metabolized to N,O-didesmethylvenlafaxine (DDV). VEN is a racemic mixture of the S- and R-enantiomers and these have in vitro displayed different degrees of serotonin and noradrenaline reuptake inhibition. The aim of the study was to investigate if an enantioselective analysis of VEN and its metabolites, in combination with genotyping for CYP2D6, could assist in the interpretation of forensic toxicological results in cases with different causes of deaths. Concentrations of the enantiomers of VEN and metabolites were determined in femoral blood obtained from 56 autopsy cases with different causes of death. The drug analysis was done by liquid chromatography tandem mass spectrometry (LC/MS/MS) and the CYP2D6 genotyping by PCR and pyrosequencing. The mean (median) enantiomeric S/R ratios of VEN, ODV, NDV and DDV were 0.99 (0.91), 2.17 (0.93), 0.92 (0.86) and 1.08 (1.03), respectively. However, a substantial variation in the relationship between the S- and R-enantiomers of VEN and metabolites was evident (S/R ratios ranging from 0.23 to 17.6). In six cases, a low S/R VEN ratio (mean 0.5) was associated with a high S/R ODV ratio (mean 11.9). Genotyping showed that these individuals carried two inactive CYP2D6 genes indicating a poor metabolizer phenotype. From these data we conclude that enantioselective analysis of VEN and ODV can predict if a person is a poor metabolizer genotype/phenotype for CYP2D6. Knowledge of the relationship between the S- and R-enantiomers of this antidepressant drug and its active metabolite is also important since the enantiomers display different pharmacodynamic profiles.

A validated, accurate and sensitive LC-MS/MS method for determination of racemic methylphenidate and its metabolite ritalinic acid has been developed. The analytes were quantified by tandem mass spectrometry operating in positive electrospray ionization mode with multiple reaction monitoring. Blood, plasma and oral fluid samples of 100 mu l were prepared by simple precipitation with 200 RI of an aqueous solution of zinc sulphate in methanol. Corresponding deuterated internal standards were used for quantification. Calibrations for methylphenidate and ritalinic acid were linear within the selected range of 0.2-30 ng/ml and 10-1500 ng/ml in blood or plasma and in the range of 1-500 ng/ml and 0.25-125 ng/ml in oral fluid, respectively. The method was successfully applied for the analysis of samples from patients treated with methylphenidate in the dose range of 36-72 mg/day and some representative ante mortem and post mortem samples from clinical and forensic toxicological investigations. A three to fourfold higher concentration of methylphenidate was found in oral fluid compared with blood while for ritalinic acid the concentrations were about 25-fold lower in oral fluid.

The primary aim of the present study was to investigate the relationship between steady state serum and cerebrospinal fluid (CSF) concentrations of olanzapine (OLA) and its metabolite 4-N-desmethylolanzapine (DMO) in patients with schizophrenia or schizoaffective disorder treated with oral OLA as the only antipsychotic drug. The influence of smoking, gender, age, as well as polymorphisms in cytochrome P450 CYP2D6, CYP1A2, and ABCB1 genes on the serum and CSF drug levels was also analyzed. Thirty-seven white outpatients (10 smokers and 27 nonsmokers) were included. From 29 of them, CSF was collected successfully. A strong correlation (Spearman rank correlation [r(s)] = 0.93; P = 0.05) was found between serum and CSF concentrations of OLA and a somewhat weaker correlation (r(s) = 0.5; P = 0.05) between those of DMO. The CSF concentrations of OLA and DMO were on average 12% and 16% of those in serum. Extensive metabolizers of CYP2D6 had higher (P = 0.05) daily doses than poor metabolizers when the influence of smoking was taken into account. Smokers had lower (P = 0.01) concentration-to-dose ratios of OLA in serum (mean, 2.23 ng/mL per mg vs 3.32 ng/mL per mg) and CSF (0.27 ng/mL per mg vs 0.41 ng/mL per mg) than nonsmokers. The concentration-to-dose ratio for serum DMO decreased with increasing age (r(s) = -0.41; P = 0.05). Carriers of ABCB1 1236T/2677T/3435T haplotype had higher serum (mean, 37.7 ng/mL vs 22.5 ng/mL; P = 0.035) and CSF (4.7 ng/mL vs 2.6 ng/mL; P = 0.018) OLA concentrations than patients without this haplotype. The present study shows a strong correlation between serum and CSF concentrations of OLA, indicating that concentrations of OLA in serum reflect those in CSF.

Background: The thiopurine drugs, 6-mercaptopurine, azathioprine, and thioguanine, are used in the treatment of acute lymphoblastic leukaemia (ALL). During treatment the thioguanine nucleotides formed are incorporated into the DNA, causing apoptosis due to the cells inability to repair the resulting damage. This mechanism is believed to be important for the effects of thiopurine drugs. We have developed a novel method for the determination of thioguanine incorporation into DNA which is both faster and cheaper than earlier methods.

Monitoring the effects of thiopurine treatment by measuring thiopurine metabolites in erythrocytes has proven to be elusive due to the lack of good correlation between measured concentrations and thiopurine effects. If the incorporation is the main mechanism of thiopurine action, a reliable method capable of measuring the incorporation in an ordinary blood sample, such as the method we have developed, should provide a significantly better correlation with treatment effect.

Material and Methods: Briefly, DNA extracted from buffy coat is degraded using nuclease P1 and alkaline phosphatase to produce free nucleosides which are purified by filtration. Thioguanosine and thymidine are separated and detected using an LC-MS/MS system and the ratio between the bases provides a measurement of the extent of thioguanine incorporation in DNA. The method has been successfully applied to cell culture samples as well as samples from patients treated orally with thiopurines.

Results: In 8 inflammatory bowel disease patients treated with azathioprine the measured incorporation ranged from 2.2 to 8.4 thioguanine bases for every 10 000 thymidine bases (median 5.2). This is in agreement with earlier reports on incorporation in childhood leukemia patients.

Conclusions: With the presented method it is possible to determine the incorporation of thioguanine into DNA during thiopurine treatment in a cost effective manner, but further research is needed to determine if there is a place for this type of methods in the monitoring of thiopurine treatment.

An ongoing study aims to compare the incorporation to treatment effects as well as conventional measurements of erythrocyte metabolite levels. By this study we hope to determine if incorporation is a more reliable measurement to predict treatment effect and if the erythrocyte metabolite levels correlate with the incorporation.

According to in vitro studies the enantiomers of venlafaxine display different degrees of serotonin and noradrenaline reuptake inhibition. Therefore, clarification of the enantiomeric drug distribution between serum and brain is highly warranted. To elucidate if P-glycoprotein (P-gp) in a stereoselective manner transports venlafaxine and its metabolites out of the brain we used abcb1ab double-knockout mice that do not express P-gp. A single dose of racemic venlafaxine (10 mg/kg bw) was intraperitoneally injected to knockout (-/-) and wildtype (+/+) mice. Serum and brain samples were collected 1, 3, 6 and 9 h following drug administration for analysis by LC/MS/MS. One to six hours post-dose, the brain concentrations of venlafaxine, O-desmethylvenlafaxine and N-desmethylvenlafaxine were 2-3, 2-6 and 3-12 times higher in abcb1ab (-/-) mice compared to abcb1ab (+/+) mice, respectively. No major differences in the serum and brain disposition of the S- and R-enantiomers of venlafaxine and its metabolites were found between the groups. We conclude that P-gp decreases the penetration of the S- and R-enantiomers of venlafaxine and its major metabolites into the brain. No evidence of a stereoselective P-gp mediated transport of these substances was observed.

A validated, accurate and sensitive LC-MS/MS method for determination of olanzapine and its metabolite N-desmethylolanzapine has been developed. The analytes were quantified by tandem mass spectrometry operating in positive electrospray ionization mode with multiple reaction monitoring. Olanzapine and desmethylolanzapine were extracted from serum or cerebral spinal fluid samples, 200 microl, with tert-butyl methyl ether using olanzapine-D3 as internal standard. Calibrations for olanzapine and desmethylolanzapine were linear within the selected range of 0.2-30 ng/ml (6-96 nM) in cerebral spinal fluid and for olanzapine in plasma, in the range of 5-100 ng/ml (16-320 nM). The method was successfully used for the analysis of samples from patients treated with olanzapine in the dose range of 2.5-25mg/day.

Background:  The relationship  between serum and CSF concentrations  of olanzapine  (OLA)  in humans  has  to our  knowledge not been described earlier. Few studies have investigated how the CYP2D6 and CYP1A2 polymorphisms affect OLA pharmacoki- netics in humans [1] [2]. Polymorphisms in the ABCB1 gene have been associated with altered pharmacokinetics of certain drugs including risperidone [3].The aim of the present study was to investigate the relationship between steady state serum and cerebrospinal fluid (CSF) con- centrations of OLA and its metabolite 4t -N-desmethylolanzapine (DMO) and to address the influence  of smoking,  gender, age as well as polymorphisms in genes coding for OLA metabolism (CYP2D6, CYP1A2) and transport (ABCB1) in patients with schizophrenia  or schizoaffective  disorder, treated with oral OLAas the only antipsychotic  drug.

Methods: Thirty seven Caucasian outpatients (10 smokers and27 non-smokers),  suffering from schizophrenia or schizoaffective disorder according to DSM-IV criteria were included in the study. From 29 out of them, CSF was collected successfully.Fasting blood samples were collected in the morning for analy- ses of OLA and DMO and for genotyping (polymorphisms of CYP2D6,  CYP1A2  and  ABCB1).  Lumbar  puncture  was  per- formed  at close  connection  to blood  sampling  at the minimum of eight hours in the fasting state. The blood and CSF samples were stored at −70ºC until analysed.A validated accurate and sensitive LC-MS/MS method was used for the analysis of OLA and DMO. Analytes were quantified  by using linear gradient reversed phase chromatography with tandem mass  spectrometry  detection  operating  in  positive  electro-sprayionization mode with multiple reactions monitoring (MRM).

Results:  A  strong  correlation  (rs =0.93;  p < 0.05)  was  foundbetween serum and CSF concentrations  of OLA and a somewhatweaker (rs =0.5; p < 0.05) between those of DMO. The CSF con- centrations  of  OLA  and  DMO  were  in  average  13%  and  16% of those in serum. Extensive metabolizers of CYP2D6 were pre- scribed higher (p < 0.05) daily doses than poor metabolizers when the influence of smoking habits was taken into account. Smokers had  lower  concentration-to-dose   ratios  (C/D)  of  OLA  both  in serum and CSF than non-smokers  (median  7 vs. 10 nmol/L/mg in serum and 0.8 vs. 1.3 nmol/L/mg  in CSF; p < 0.01). C/D for serum DMO decreased with increasing age (rs = −0.41; p < 0.05). Carriers of ABCB1 1236T/2677T/3435T haplotype had higher serum (median 112 vs. 80 nmol/L; p < 0.05) and CSF (13.7 vs. 8.1 nmol/L; p < 0.05) OLA concentrations  than patients without this haplotype. Patients treated with benzodiazepines and/or zopiclone (n = 8) had higher DMO and DMO/OLA ratio (p < 0.05 for both) in CSF compared to patients not co-medicating  with these drugs (n = 21), even when smoking habits were taken into account.

Conclusion:  The present study shows a very good correlation between  serum and CSF concentrations  of OLA, indicating  thatconcentrations  of OLA in serum reflect the situation in CSF.

References

[1]  Hägg S, Spigset O, Lakso H, et al. Olanzapine disposition in humans is unrelated to CYP1A2 and CYP2D6 phenotypes. Eur J Clin Pharmacol2001;57:493−97.

[2]  Carrillo  JA, Herra´iz  AG, Ramos SI, et al. Role of smoking-inducedcytochrome P450 (CYP)1A2 and polymorphic CYP2D6 in steady-stateconcentration of olanzapine. J Clin Psychopharmacol 2003;23:119−27.

[3]  Gunes A, Spina E, Dahl M-L, et al. ABCB1 polymorphisms influencesteady-state  plasma  levels  of  9-hydroxyrisperidone   and  risperidoneactive moiety. Ther Drug Monit 2008;30:628−33.

A stereoselective method is described for simultaneous determination of the S- and R-enantiomers of venlafaxine and its three demethylated metabolites in human plasma and whole blood samples. This validated method involved LC/MS/MS with positive electrospray ionization and solid phase extraction. Chromatographic separation was performed on a 250 mm x 2.1mm Chirobiotic V column with a total run time of 35 min. In plasma, calibration curves were in the range of 1-1000 nM for the S- and R-enantiomers of venlafaxine and O-desmethylvenlafaxine, and 0.5-500 nM for N-desmethylvenlafaxine and N,O-didesmethylvenlafaxine. In whole blood the corresponding concentrations were 10-4000 and 5-2000 nM, respectively. The intra-day precision was <6.3% and the inter-day precision was <9.9% for plasma and <15% and <19% for whole blood. LLOQ ranged between 0.25 and 0.5 nM. No ion suppression/enhancement or other matrix effects were observed. The method was successfully applied for determination of venlafaxine and its metabolites in plasma from patients and whole blood samples from forensic autopsy cases.

A stationary phase combining zwitterionic ion chromatography and hydrophilic interaction chromatography (ZIC-HILIC) from SeQuant was evaluated for the chromatography of some opiates and their polar metabolites. The effects of mobile phase constitution on retention and resolution were extensively evaluated. Different aspects of mobile phase constitution such as ion strength and type of buffer, type and amount of organic modifier and pH were examined. The selectivity and retention of the opiates compared to their glucuronides could be substantially altered with small changes of the mobile phase, especially when the type of buffer, i.e., formate, or acetate and organic modifier, i.e., acetonitrile or methanol were changed. The retention on the ZIC-HILIC was dominated by hydrophilic interaction chromatography (HILIC) but considerable effects on the selectivity was observed, possibly caused by an ion exchange mechanism due to interactions with the charges on the stationary phase.

Alternative strategies for sample preparation of human blood samples were evaluated including protein precipitation (PP) and solid phase extraction (SPE) on Waters Oasis^® polymeric columns. Gradient chromatography within 15 min was performed on a Hypersil Polar-RP column combined with a Sciex API 2000 triple quadrupol instrument equipped with an electro-spray interface. Beta-agonists and beta-antagonists available on the Swedish market were included in the study. A combination of zinc sulphate and ethanol was found effective for PP. A clear supernatant was achieved that either could be injected directly on the LC–MS–MS system for analysis or transferred to a SPE column for further extraction and analyte concentration. Retention on the hydrophilic–lipophilic balanced sorbent HLB as well as the mixed mode cationic MCX and anionic MAX sorbents were investigated. On HBL the relative lipophilicity of the target analytes was investigated. At a high pH when the amino alcohols are deprotonised the more non-polar analytes (e.g., carvediol, betaxolol, bisoprolol and propranolol) were well retained on the sorbent and for the majority methanol content higher than 50% in water (v/v) was needed for elution. Some analytes though, with additional weak acidic functionalities (fenoterol, salbutamol, sotalol, and terbutaline) were poorly retained. On MAX the retention of these weak acids was improved when loaded under basic conditions but under neutral conditions analyte recoveries was comparable with HLB. On MCX all the analytes were well retained allowing a wash step of 100% methanol at neutral and low pH. By applying the supernatant from PP in combination with an additional portion of aqueous formic acid (2%) the analytes could be loaded and retained. High extraction recoveries were found for most analytes but for a few, significant losses were seen during PP (e.g., formoterol) and/or evaporation (e.g., fenoterol, formoterol, labetalol and terbutaline). The effectiveness of the sample preparation was evaluated by ESI ion-suppression studies by post column infusion of the target analyte. An ethanol zinc sulphate aq mixture was found to be more effective than acetonitrile, methanol or ethanol for PP of human whole blood samples. Beside suppression by salts in the front peak, only limited suppression from other artefacts such as more lipophilic compounds was found late in the chromatograms. Some tendency though to concentrate more lipophilic artefacts on the Oasis^® sorbents was seen. These findings show that the Oasis MCX sorbent is well suited for sample preparation of beta-agonists and beta-antagonists from human whole blood if the objective is to cover a great number of the analytes in the same assay.

A diversity of pharmacological effects on the cardiovascular system have been reported for Camellia sinensis: antioxidative, antiproliferative and anti-angiogenic activity, and nitric oxide synthase activation. The purpose of this study was to investigate if the connection between tea and angiotensin-converting enzyme (ACE) and nitric oxide (NO) might be an explanation of the pharmacological effects of tea on the cardiovascular system. Cultured endothelial cells from human umbilical veins (HUVEC) were incubated with extracts of Japanese Sencha (green tea), Indian Assam Broken Orange Pekoe (black tea) and Rooibos tea, respectively. The main flavanols and purine alkaloids in green and black tea were examined for their effects on ACE and NO. After incubation with green tea, black tea and Rooibos tea for 10 min, a significant and dose-dependent inhibition of ACE activity in HUVEC was seen with the green tea and the black tea. No significant effect on ACE was seen with the Rooibos tea. After 10-min incubation with (-)-epicatechin, (-)- epigallocatechin, (-)-epicatechingallate and (-)-epigallocatechingallate, a dose-dependent inhibition of ACE activity in HUVEC was seen for all four tea catechins. After 24-h incubation, a significantly increased dose-dependent effect on NO production in HUVEC was seen for the green tea, the black tea and the Rooibos tea. After 24-h incubation with (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechingallate and (-)-epigallocatechingallate, a dose-dependent increased NO production in HUVEC was seen. In conclusion, tea extracts from C. sinensis may have the potential to prevent and protect against cardiovascular disease. © 2006 The Authors.

Patients with asthma are a target group for medication with β2-agonists, often in combination with corticosteroids. Salbutamol is commonly marketed as racemate. R-Salbutamol carries β2-agonistic property whereas S-salbutamol does not. The racemate undergoes stereoselective sulphatisation by sulfotransferases mainly in the gut and liver, so that S-salbutamol rests for a longer time in the body and reaches higher plasma levels than R-salbutamol. Ten patients with mild stable asthma and at present without cortisone medication were given racemic salbutamol as ventoline 4 mg orally. Plasma and urine levels were estimated until 24 hr after ingestion. For comparison healthy volunteers were treated in the same way.The group of asthma patients was then treated with budesonide inhalations 800 μg daily for one week and the initial programme resumed. Non-cortisone-treated asthmatic patients displayed higher levels of both R- and S-salbutamol in plasma than did healthy volunteers after one single ingestion of racemic salbutamol (CMAX both comparisons P<0.05). Plasma levels of salbutamol isomers in cortisone-treated asthmatic patients resembled the levels in volunteers. The most plausible explanation for the discrepancy in values between asthmatic patients and volunteers is a defective metabolic function by asthmatic patients possibly enzymatic in origin.

Racemic salbutamol, a β₂-adrenoceptor agonist used for dilatation of airways, has recently been shown to induce lessened relaxation of bronchial smooth muscle and partial loss of bronchoprotection, seen as increased hyperresponsiveness, after regular treatment. The racemate undergoes stereo-selective disposition, giving higher plasma levels of S-salbutamol than that of bronchodilating R-salbutamol, thus raising S : R ratios after repeated administration. Our aim was to evaluate whether increased bronchial hyperresponsiveness (BHR) could be found even after 1 day of repeated salbutamol inhalations, with β₂-receptor-induced bronchial smooth muscle relaxation remaining and whether this would be associated with plasma levels of either enantiomer. Fifteen patients with stable asthma, aged 19–54 years, were included in a randomized, cross-over study. An indirect bronchial challenge method was used [voluntary isocapnic hyperventilation of cold air (IHCA)], and airway condition tested by means of impulse oscillometry. Racemic salbutamol was inhaled three times during a 6-h period. IHCA was performed and plasma concentrations of enantiomers were measured 4 h after the last dose. Tests were also performed without preceding drug treatment. β₂-Agonist-produced bronchial dilatation and protection persisted in the majority of the 15 patients 4 h after repeated inhalations of salbutamol during 1 day. In only two of the 15 patients we could trace increased BHR after salbutamol. Neither dilatation nor protection could be linked to plasma levels of either R- or S-salbutamol. The underlying mechanisms of BHR remain unknown and are dissociated from β₂-receptor-mediated dilatation.

The aim of this study was to develop a liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for the analysis of benzodiazepines in human hair. The method was tested by analyzing hair samples from forensic and clinical psychiatric patients where benzodiazepines had been prescribed during hospitalization and after care. Hair samples were obtained at discharge from the clinic and then after six months. Two-centimeter segments of the hair samples (10–30 mg) were washed once with isopropanol, three times with phosphate buffer, and again with isopropanol, dried, weighed, and digested with proteinase K before solid-phase extraction with BondElut Certify columns. Diazepam, nordiazepam, oxazepam, alprazolam, OH-alprazolam, nitrazepam, 7-aminonitrazepam, flunitrazepam, 7-aminoflunitrazepam, clonazepam, and 7-aminoclonazepam were quantitated in MRM mode using one transition for each analyte and deuterated internal standard. The calibration range was 0.125–5 ng/mg for diazepam, nordiazepam, and oxazepam and 0.025–1.0 ng/mg for the other compounds. In the hair samples analyzed, diazepam, flunitrazepam, nitrazepam, and clonazepam was detected together with their metabolites. Alprazolam was not detected in any sample. Segmental hair analysis revealed differences in drug deposition in hair before and after release from psychiatric treatment. Both increases and decreases of hair drug concentrations were seen after release even though the prescribed dose was the same. This was taken as an indication of noncompliance during the after-care period. We conclude that the extraction and LC-MS-MS procedures were adequate to detect benzodiazepines in hair and that the results indicated that segmental hair analysis might provide retrospective information about medication intake.

high-performance liquid chromatography method capable of measuring thiopurine mono-, di-, and triphosphates separately in red blood cells (RBCs) was developed. RBC:s were isolated from whole blood using centrifugation. Proteins were precipitated using dichloromethane and methanol. The thioguanine nucleotides (TGNs) were derivatised using potassium permanganate before analysis. Analytes were separated by ion-pairing liquid chromatography using tetrabutylammonium ions and detected using UV absorption and fluorescence. The method was designed for use in clinical trials in thiopurine therapy and proven valid by analysis of authentic patient samples.

The method measured thioguanosine mono- (TGMP), di- (TGDP), and triphosphate (TGTP), as well as methylthioinosine mono- (meTIMP), di- (meTIDP) and triphosphate (meTITP) in RBCs collected from patients treated with thiopurine drugs (azathioprine, 6-mercaptopurine, and 6-thioguanine).

LOQ was 0.3, 3, 2, 30, 30 and 40 pmol/8x10^8 RBC, for TGMP, TGDP, TGTP, meTIMP, meTIDP and meTITP, respectively. Between-day precision were below 14% for all analytes at all concentrations and samples were stable at 5 °C for 8 hours after sampling.

Venlafaxine is a frequently prescribed racemic antidepressant drug worldwide, consisting of two enantiomers that exhibit similar but not identical biological activity profiles. Venlafaxine is extensively metabolised by the cytochrome P450 (CYP) system. CYP2D6 is involved in the formation of O-desmethylvenlafaxine (Odm-venlafaxine) and CYP3A4 in the formation of Ndesmethylvenlafaxine (Ndm-venlafaxine). The female Dark Agouti and Sprague-Dawley rats are considered the animal counterparts of the human CYP2D6 poor and extensive metaboliser phenotypes, respectively. Since CYP2D6 seems to play a major role in the metabolism of venlafaxine, the aim of this work was to study possible differences in the pharmacokinetics of the enantiomers of venlafaxine and its metabolites in these two different rat strains. Following single administration of racemic venlafaxine (15 mg/kg) serum and brain samples were collected and the concentrations of the enantiomers of venlafaxine and its three major metabolites were determined using an enantioselective LC/MS/MS method. Higher serum and brain concentrations of venlafaxine were observed in Dark Agouti rats as compared to Sprague-Dawley rats (p=0.0002). In relation to the Odm-venlafaxine concentration, the Ndmvenlafaxine concentrations were much higher in Dark Agouti rats than in Sprague-Dawley rats (p<0.0001). The enantiomeric (S/R) venlafaxine ratios were almost two times higher in Dark Agouti rats than in Sprague-Dawley rats, which was observed in both serum and brain (p<0.0001). The present results give hints for possible differences in the pharmacokinetics of venlafaxine in human extensive and poor metaboliser CYP2D6 phenotype subjects.