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Cyclosporine A, immunoassay, immunosuppressant drugs, liquid chromatography-tandem mass spectrometry (LC-MS/MS), therapeutic drug monitoring Recently, the CsA immunoassay was reformulated (ref: LN 3R30) to improve assay imprecision of the previous on-market assay (ref: LK 1L75). Keywords: cyclosporine A; immunoassay; immunosuppressant drugs; liquid chromatography-tandem mass spectrometry (LC-MS/MS); therapeutic drug monitoring EN cyclosporine A immunoassay immunosuppressant drugs liquid chromatography-tandem mass spectrometry (LC-MS/MS) therapeutic drug monitoring e209 e212 4 04/12/21 20210501 NES 210501 To the Editor, Cyclosporine A (CsA) is an immunosuppressant drug (ISD) used to prevent transplant rejection after organ transplantation. Assay imprecision (within-run, between-run and total imprecision) was evaluated, both for the immunoassays as for the LC-MS/MS method, following the Clinical and Laboratory Standards Institute protocol EP5-A3 and using three Lyphocheck Whole Blood Immunosuppressant Controls, level 1, 2 and 3 (Bio-Rad Laboratories, Hercules, CA; LOT: 26270, EXP: 09/2021) [[10]]. [Extracted from the article]

Aim A major problem in assessing the true public health impact of drug-use on driving and overall traffic safety is that the variables being measured across studies vary significantly. In studies reported in a growing global literature, basic parameters assessed, analytical techniques and drugs tested are simply not comparable due to lack of standardization in the field. These shortcomings severely limit the value of this research to add knowledge to the field. A set of standards to harmonize research findings is sorely needed. This project was initiated by several international organizations to develop guidelines for research on drugged driving. Methods A September 2006 meeting of international experts discussed the harmonization of protocols for future research on drugged driving. The principal objective of the meeting was to develop a consensus report setting guidelines, standards, core data variables and other controls that would form the basis for future international research. A modified Delphi method was utilized to develop draft guidelines. Subsequently, these draft guidelines were posted on the internet for global review, and comments received were integrated into the final document. Results The Guidelines Document is divided into three major sections, each focusing upon different aspects of drugged driving research (e.g. roadside surveys, prevalence studies, hospital studies, fatality and crash investigations, etc.) within the critical issue areas of ‘behavior’, ‘epidemiology’ and ‘toxicology’. The behavioral section contains 32 specific recommendations; (2) epidemiology 40 recommendations; and (3) toxicology 64 recommendations. Conclusions It is anticipated that these guidelines will improve significantly the overall quality of drugged driving research and facilitate future cross-study comparisons nationally and globally. [ABSTRACT FROM AUTHOR]

Presents a comparison of the sensitivity and specificity of six immunoassays for the detection of amphetamines in urine. Confirmation of all samples that screened positive by any amphetamine screening method and 15 percent of the negative samples; Factor to be considered if a sample is positive for amphetamines; Variation of the areas under the receiver operating characteristic curve.

Abstract: In recent years the demand for drug testing in oral fluid in cases of driving under the influence has been increasing. The main advantages of saliva/oral fluid are the possibility for non-medical personnel to collect it without embarrassment and a better correlation between presence of drugs in oral fluid and impairment. Several surveys have been performed since the 1980s using saliva, and researchers encountered problems related to insufficient sample volume and insufficient sensitivity of the analytical methods. Steady progress has been shown in sample collection, knowledge of toxicokinetics in oral fluid, reliability of on-site and laboratory-based immunoassays and confirmation methods. In a few countries, legislation was passed that allows the use of saliva as a matrix for screening or confirmation. Despite this progress, some more work needs to be done, principally in the areas of the sensitivity and reliability of on-site screening devices, particularly for cannabis and benzodiazepines, knowledge about passive contamination and more generalised proficiency testing before oral fluid testing for DUID will have the reliability needed to be used forensically. [Copyright &y& Elsevier]

Liquid chromatography–tandem mass spectrometry (LC–MS–MS) is often performed in a high-throughput environment. Unfortunately, with atmospheric pressure ionization (API) techniques, shorter run-times or reduced sample clean-up often result in ion or matrix suppression, which can lead to erroneous results. The present work on the analysis of paclitaxel compares ion suppression, sensitivity and linearity of a high-throughput LC–MS–MS method (0.8 min run-time, method B) to a method with increased separation (2.0 min run-time, method A). An atmospheric pressure chemical ionization (APCI) interface was used for both methods. The high-sample-throughput method uses an increased amount of organic solvent in the mobile phase (isocratic, 85% versus 70% of methanol) and a higher flow-rate (600 μl/min versus 400 μl/min). As a result, internal standard (docetaxel) and target analyte (paclitaxel) co-elute, close to, although separated from the solvent front. Ion suppression of both methods was evaluated by comparing pure standard to plasma and plasma containing a vehicle. Sensitivity and linearity were compared by injecting matrix matched calibration samples with both methods. Ion suppression by the vehicle Cremophor EL led to poor data quality for the standard method (A), while for the short method (B), ion suppression was compensated for by the co-eluting internal standard. The short method showed similar linearity but increased sensitivity by at least a factor five. This work provides a strategy to compensate for ion suppression without the use of labeled internal standards. In addition, a better sensitivity and a shorter run-time are noted. [Copyright &y& Elsevier]

Describes a case report of the sudden awakening from a near coma of a 23-year old female, after ingestion of gamma-hydroxybutyric acid (GHB), ethanol, and cannabinoids. Amount of GHB and ethanol found; Techniques used to identify the substances; How the case illustrates the consequences of GHB overdose.

Unlabelled: We report the presence of iopromide in the bowel and urine of a preterm infant, born 10 days after intravenous administration of the nonionic monomer to his mother. Excessive urinary iodine excretion and borderline hyperthyrotropinaemia were observed in the infant. Moreover, crossing of the fetal blood-brain barrier was demonstrated by detection of the angiographic material in CSF and thus direct fetal neurotoxic effects cannot be excluded.Conclusion: These widely used contrast media may cross the placenta and accumulate in various fetal tissues in significant amounts causing possible neonatal toxicity. Therefore the perinatal safety of these diagnostic agents should at least be questioned. [ABSTRACT FROM AUTHOR]

• The prevalence of psychoactive drugs in the blood of Italian drivers was studied. • The highest prevalence was found for alcohol (17.3%), followed by medications (13.6%). • The prevalence of Benzodiazepines (7.3%) was much higher than in previous studies. • Antidepressants/antipsychotics and medical opioids had a prevalence of 7.2% and 3.1%. • Medications were mostly found in females and in drivers older than 60-year-old. Psychoactive medicines, such as benzodiazepines and Z-drugs (BdZ), antidepressants and antipsychotics (AA) and medical opioids (MO), have an impairing effect on driving ability. In previous epidemiological studies performed on impaired and/or injured drivers, not all relevant psychoactive substances were included in the toxicological assessment, and their prevalence may be underestimated. This study aims to assess the prevalence of a large set of psychoactive substances (n = 53) in Italian drivers involved in a road traffic crash and in predefined population subgroups. The toxicological analyses were performed on the whole blood of 1026 drivers involved in a road traffic crash in the area of Bologna, Italy, from January 2017 to March 2018. Analyses were performed using GC-FID (alcohol), GC MS (illicit drugs) and LC/HRMS (psychoactive drugs). The population was divided into subgroups according to gender, age and crash time. Descriptive statistics were used in order to assess differences among sub-groups. The highest prevalence was found for alcohol (17.3%), followed by medicinal drugs (13.6%) and illicit drugs (5.5%). The prevalence of BdZ, AA and MO were 7.3%, 7.2% and 3.1%, respectively. The frequency of BDZ and AA was significantly higher in female drivers and showed higher prevalence at increasing age. The presence of medicinal drugs was significantly higher during the week and in crashes occurring during the day. Results for alcohol and illicit drugs partially overlap with those reported in previous European and Italian studies, but the prevalence of BdZ was much higher. We also found a high prevalence of AA, which are rarely investigated in epidemiological studies performed on drivers, but may cause impairment of the ability to drive, especially when taken in combination with alcohol or other drugs. The pattern of medication use differs from that involving drugs of abuse, since it is mainly observed in female subjects and older drivers and does not follow the same weekly trend observed for alcohol and other illicit drugs. [ABSTRACT FROM AUTHOR]

Introduction: Psychoactive medicines, such as benzodiazepines and Z-drugs (BdZ), antidepressants and antipsychotics (AA) and medical opioids (MO), have an impairing effect on driving ability. In previous epidemiological studies performed on impaired and/or injured drivers, not all relevant psychoactive substances were included in the toxicological assessment, and their prevalence may be underestimated. This study aims to assess the prevalence of a large set of psychoactive substances (n=53) in Italian drivers involved in a road traffic crash and in predefined population subgroups.Materials and Methods: The toxicological analyses were performed on the whole blood of 1026 drivers involved in a road traffic crash in the area of Bologna, Italy, from January 2017 to March 2018. Analyses were performed using GC-FID (alcohol), GCMS (illicit drugs) and LC/HRMS (psychoactive drugs). The population was divided into subgroups according to gender, age and crash time. Descriptive statistics were used in order to assess differences among sub-groups.Results: The highest prevalence was found for alcohol (17.3%), followed by medicinal drugs (13.6%) and illicit drugs (5.5%). The prevalence of BdZ, AA and MO were 7.3%, 7.2% and 3.1%, respectively. The frequency of BDZ and AA was significantly higher in female drivers and showed higher prevalence at increasing age. The presence of medicinal drugs was significantly higher during the week and in crashes occurring during the day.Conclusion: Results for alcohol and illicit drugs partially overlap with those reported in previous European and Italian studies, but the prevalence of BdZ was much higher. We also found a high prevalence of AA, which are rarely investigated in epidemiological studies performed on drivers, but may cause impairment of the ability to drive, especially when taken in combination with alcohol or other drugs. The pattern of medication use differs from that involving drugs of abuse, since it is mainly observed in female subjects and older drivers and does not follow the same weekly trend observed for alcohol and other illicit drugs. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To validate a method for determining equivalent drug cutoff concentrations for tetrahydrocannabinol and amphetamine in blood and oral fluid, which ensures that the drug prevalence in samples of blood and oral fluid taken simultaneously is equal. Methods: A method using regression analysis of drug concentrations for defined percentiles in blood and oral fluid was developed. The accuracy and precision of this technique was investigated. As study populations, 311 cannabis users and 197 amphetamine users from the Rosita-2 Project were used. Results: A total of 80 paired oral fluid and blood concentrations were needed to determine accurate regression formulae. When using the formulae to calculate drug cutoff concentrations in oral fluid corresponding to 2.0, 4.0, 6.0, 8.0 and 10.0ng/ml tetrahydrocannabinol in blood and 200, 400, 600, 800 and 1000ng/ml amphetamine in blood, the accuracy was better than 100±20% compared to actual prevalence in blood with precision better than ±20%. Conclusion: Prevalence regression may be a useful tool in estimating equivalent cutoff concentrations in blood and oral fluid. [Copyright &y& Elsevier]

For many drugs, there is a poor correlation between the plasma and oral fluid (OF) concentrations, due to differences in OF pH, oral contamination, stimulation of OF flow and variability of the volume of sample taken. The aim of this study was to evaluate the OF/plasma ratio and variability in drug concentration in OF sampled by two commercially available collection systems: Saliva Collection System (SCS) and Quantisal. Blood and OF samples were collected from 12 volunteers after intake of 19.5 mg codeine phosphate. Six persons were sampled by SCS first, followed by Quantisal; six other participants used Quantisal before SCS. The OF content of SCS tubes was measured spectrophotometrically. The Quantisal devices were weighed to correct for the effectively obtained OF volume. Codeine was measured by gas chromatography-mass spectrometry. The mean codeine concentration at 1 h was 29.8 ± 18.8 µg/L in plasma, 72.8 ± 63.9 µg/L in SCS OF and 85.3 ± 72.6 µg/L in Quantisal OF. The mean OF/plasma ratio was 2.30 ± 0.77 (SCS) and 2.69 ± 1.94 (Quantisal). Pearson's correlation coefficient between OF and plasma codeine concentrations was statistically significantly (P = 0.005) higher for SCS (R² = 0.745) than for Quantisal (R² = 0.403). The variability in ratios with Quantisal wasmarkedly reduced when used after SCS. Codeine concentrationsmeasured in OF taken with SCS correlate better with plasma concentrations than in OF obtained with Quantisal, particularly when Quantisal was used first. [ABSTRACT FROM AUTHOR]

Background: Beta-lactam antimicrobial concentrations are frequently suboptimal in critically ill patients. Population pharmacokinetic (PopPK) modeling is the golden standard to predict drug concentrations. However, currently available PopPK models often lack predictive accuracy, making them less suited to guide dosing regimen adaptations. Furthermore, many currently developed models for clinical applications often lack uncertainty quantification. We, therefore, aimed to develop machine learning (ML) models for the prediction of piperacillin plasma concentrations while also providing uncertainty quantification with the aim of clinical practice.Methods: Blood samples for piperacillin analysis were prospectively collected from critically ill patients receiving continuous infusion of piperacillin/tazobactam. Interpretable ML models for the prediction of piperacillin concentrations were designed using CatBoost and Gaussian processes. Distribution-based Uncertainty Quantification was added to the CatBoost model using a proposed Quantile Ensemble method, useable for any model optimizing a quantile function. These models are subsequently evaluated using the distribution coverage error, a proposed interpretable uncertainty quantification calibration metric. Development and internal evaluation of the ML models were performed on the Ghent University Hospital database (752 piperacillin concentrations from 282 patients). Ensuing, ML models were compared with a published PopPK model on a database from the University Medical Centre of Groningen where a different dosing regimen is used (46 piperacillin concentrations from 15 patients.).Results: The best performing model was the Catboost model with an RMSE and [Formula: see text] of 31.94-0.64 and 33.53-0.60 for internal evaluation with and without previous concentration. Furthermore, the results prove the added value of the proposed Quantile Ensemble model in providing clinically useful individualized uncertainty predictions and show the limits of homoscedastic methods like Gaussian Processes in clinical applications.Conclusions: Our results show that ML models can consistently estimate piperacillin concentrations with acceptable and high predictive accuracy when identical dosing regimens as in the training data are used while providing highly relevant uncertainty predictions. However, generalization capabilities to other dosing schemes are limited. Notwithstanding, incorporating ML models in therapeutic drug monitoring programs seems definitely promising and the current work provides a basis for validating the model in clinical practice. [ABSTRACT FROM AUTHOR]

Fast and reliable ethanol assays analysis are used in a clinical context for patients suspected of ethanol intoxication. Mostly, automated systems using an enzymatic reaction based on ethanol dehydrogenase are used. The manuscript focusses on the evaluation of the performance of these assays. Data included 30 serum samples used in the Belgian EQA scheme from 2019 to 2021 and concentrations ranged from 0.13 to 3.70 g/L. A regression line between target concentrations and reported values was calculated to evaluate outliers, bias, variability and measurement uncertainty. A total of 1,611 results were taken into account. Bias was the highest for Alinity c over the whole concentration range and the lowest for Vitros for low concentrations and Cobas 8000 using the c702 module for high concentrations. The Architect and Cobas c501/c502 systems showed the lowest variability over the whole concentration range. Highest variability was observed for Cobas 8000 using the 702 module, Thermo Scientific and Alinity c. Cobas 8000 using the c702 module showed the highest measurement uncertainty for lower concentrations. For higher concentrations, Alinity c, Thermo Scientific and Vitros were the methods with the highest measurement uncertainty. The bias of the enzymatic techniques is nearly negligible for all methods except Alinity c. Variability differs strongly between measurement procedures. This study shows that the Alinity c has a worse measurement uncertainty than other systems for concentrations above 0.5 g/L. Overall, we found the differences in measurement uncertainty to be mainly influenced by the differences in variability. [ABSTRACT FROM AUTHOR]

N-Piperidinyl etonitazene ('etonitazepipne') represents a recent addition to the rapidly expanding class of 2-benzylbenzimidazole 'nitazene' opioids. Following its first identification in an online-sourced powder and in biological samples from a patient seeking help for detoxification, this report details its in-depth chemical analysis and pharmacological characterization. Analysis of the powder via different techniques (LC-HRMS, GC–MS, UHPLC-DAD, FT-IR) led to the unequivocal identification of N-piperidinyl etonitazene. Furthermore, we report the first activity-based detection and analytical identification of N-piperidinyl etonitazene in authentic samples. LC-HRMS analysis revealed concentrations of 1.21 ng/mL in serum and 0.51 ng/mL in urine, whereas molecular networking enabled the tentative identification of various (potentially active) urinary metabolites. In addition, we determined that the extent of opioid activity present in the patient's serum was equivalent to the in vitro opioid activity exerted by 2.5–10 ng/mL fentanyl or 10–25 ng/mL hydromorphone in serum. Radioligand binding assays in rat brain tissue revealed that the drug binds with high affinity (Ki = 14.3 nM) to the µ-opioid receptor (MOR). Using a MOR-β-arrestin2 activation assay, we found that N-piperidinyl etonitazene is highly potent (EC50 = 2.49 nM) and efficacious (Emax = 183% versus hydromorphone) in vitro. Pharmacodynamic evaluation in male Sprague Dawley rats showed that N-piperidinyl etonitazene induces opioid-like antinociceptive, cataleptic, and thermic effects, its potency in the hot plate assay (ED50 = 0.0205 mg/kg) being comparable to that of fentanyl (ED50 = 0.0209 mg/kg), and > 190 times higher than that of morphine (ED50 = 3.940 mg/kg). Taken together, our findings indicate that N-piperidinyl etonitazene is a potent opioid with the potential to cause harm in users. [ABSTRACT FROM AUTHOR]

In Europe, authorities frequently ask forensic laboratories to analyze seized cannabis plants to prove that cultivation was illegal (drug type and not fiber type). This is generally done with mature and flowering plants. However, authorities are often confronted with very young specimens. The aim of our study was to evaluate when the chemotype of cannabis plantlets can be surely determined through analysis of eight major cannabinoids content during growth. Drug-type seedlings and cuttings were cultivated, sampled each week, and analyzed by high-performance liquid chromatography with diode array detection. The chemotype of clones was recognizable at any developmental stage because of high total Δ9-tetrahydrocannabinol (THC) concentrations even at the start of the cultivation. Conversely, right after germination seedlings contained a low total THC content, but it increased quickly with plant age up, allowing chemotype determination after 3 weeks. In conclusion, it is not necessary to wait for plants' flowering to identify drug-type cannabis generally cultivated in Europe. [ABSTRACT FROM AUTHOR]

A quantitative method for the simultaneous determination of docetaxel (Taxotere), paditaxel (Taxol), 6α-hydroxy- paclitaxel, and p-3'-hydroxypaclitaxel in human plasma and oral fluid is developed and validated. Oral fluid (this term is now preferred to saliva) was sampled with a Salivette collection device. The procedure used a simple liquid/liquid extraction with methyl tert-butyl ether followed by LC-ESI-MS/MS. Gradient elution was applied and provided increased robustness to ion suppression by the drug formulation vehicle (polysorbate 80 and Cremophor EL). Adduct ion formation with sodium and potassium was noticed and controlled by mobile-phase optimization. The protonated analytes generated in the positive ion mode were monitored through multiple reaction monitoring. Calibration was performed by internal standardization with cephalomannine, and regression curves were constructed ranging between 2 and 1000 ng/mL in plasma and 0.125 and 62.5 ng/mL in oral fluid, using a weighing factor of 1/x². The regression curves were quadratic for paclitaxel and docetaxel and linear for the paclitaxel metabolites. Accuracy varied from 91.3 to 103.6%, and imprecision did not exceed 12.7% for all analytes in plasma and oral fluid. In conclusion, a sensitive and robust method was obtained, which fuffilled all validation criteria. [ABSTRACT FROM AUTHOR]

• Piperacillin and meropenem concentrations are low but measurable in oral fluid of ICU patients. • Correlation was poor between oral fluid and both total and unbound plasma piperacillin concentrations. • Dispersion of antibiotic concentrations was greater in oral fluid than in blood. • Oral fluid from non-intubated ICU patients cannot be recommended for TDM. Therapeutic drug monitoring (TDM) of β-lactam antibiotics may be used to optimize dosing for patients in the intensive care unit (ICU). A noninvasive matrix such as oral fluid may be interesting in selected patient groups. We compared the oral fluid concentrations of piperacillin and meropenem with the respective unbound and total concentrations in plasma. A secondary objective was to evaluate feasibility of the collection of oral fluid samples in this specific patient population. The study included 20 non-intubated ICU patients, age 22 to 77 y, receiving piperacillin or meropenem via continuous intravenous infusion. The standard protocol consisted of collecting a paired plasma-oral fluid sample for 3 consecutive days. Oral fluid was obtained from the patients using a standardized procedure by spitting in a plastic container after 2 min of gathering oral fluid in the mouth. Antibiotic concentrations of piperacillin and meropenem are measurable, albeit very low, in unstimulated oral fluid of ICU patients. For piperacillin, a poor correlation was found between oral fluid and both total and unbound plasma concentrations (Spearman's correlation coefficients (Rs) 0.46 and 0.48 respectively). For meropenem this correlation was better (Rs for oral fluid versus total and unbound plasma meropenem concentration 0.92 and 0.93 respectively). Dispersion of antibiotic concentrations was greater in oral fluid than in blood. Collecting oral fluid samples was difficult in non-intubated ICU patients. Oral fluid from non-intubated ICU patients, obtained through a standardized procedure, cannot be recommended as an alternative matrix for quantitative meropenem or piperacillin TDM. [ABSTRACT FROM AUTHOR]

Therapeutic drug monitoring (TDM) of tyrosine kinase inhibitors (TKIs) in cancer therapy offers the potential to improve treatment efficacy while minimizing toxicity. Therefore, a high-throughput, sensitive LC-MS/MS method was developed and validated, to be used for personalized treatment of hematologic malignancies. The assay allows the simultaneous quantification in plasma (EDTA and heparin) and whole blood of eight TKIs, including bosutinib, dasatinib, gilteritinib, ibrutinib, imatinib, midostaurin, nilotinib and ponatinib, which are used in the treatment of chronic and acute myeloid leukemia (CML, AML) and chronic lymphocytic leukemia (CLL). The procedure involves simple protein precipitation of 50 μL of sample, a 4-min chromatographic separation by applying gradient elution on a standard reverse phase column, and tandem mass spectrometric detection. The method was successfully validated based on international guidelines in terms of calibration curves, precision (within-run CV 0.74–16.4%; between-run CV 1.65–17.8%), accuracy (within-run bias 0.07–19.8%; between-run bias 0.05 to −17.6%), carry-over (max 19.4%, for ponatinib), selectivity, matrix-effects, recovery (ranging from 61 to 128%), stability (only issues observed for ibrutinib) and dilution integrity. Furthermore, the accuracy of the method was demonstrated by analyzing external quality controls, with a maximum bias of −11.3%. Assay applicability was demonstrated by analyzing authentic plasma and whole blood samples in order to derive blood-plasma ratios and the variation thereof. The latter are important to allow possible blood-plasma conversion when envisaging possible future implementation of TDM via dried blood microsampling. The presented method can be applied in clinical practice for performing TDM of TKIs in plasma and whole blood samples. Image 1 • Development of a quantitative LC-MS/MS method for TKIs in plasma and whole blood. • TKIs included are used to treat hematological malignancies. • Newer TKIs midostaurin and gilteritinib used for FLT3+ AML treatment are included. • Successful application on external quality control and authentic samples. • Establishment of blood-plasma ratios of eight TKIs. [ABSTRACT FROM AUTHOR]

Summary: Objective: One third of epilepsy patients do not become seizure‐free using conventional medication. Therefore, there is a need for alternative treatments. Preclinical research using designer receptors exclusively activated by designer drugs (DREADDs) has demonstrated initial success in suppressing epileptic activity. Here, we evaluated whether long‐term chemogenetic seizure suppression could be obtained in the intraperitoneal kainic acid rat model of temporal lobe epilepsy, when DREADDs were selectively expressed in excitatory hippocampal neurons. Methods: Epileptic male Sprague Dawley rats received unilateral hippocampal injections of adeno‐associated viral vector encoding the inhibitory DREADD hM4D(Gi), preceded by a cell‐specific promotor targeting excitatory neurons. The effect of clozapine‐mediated DREADD activation on dentate gyrus evoked potentials and spontaneous electrographic seizures was evaluated. Animals were systemically treated with single (.1 mg/kg/24 h) or repeated (.1 mg/kg/6 h) injections of clozapine. In addition, long‐term continuous release of clozapine and olanzapine (2.8 mg/kg/7 days) using implantable minipumps was evaluated. All treatments were administered during the chronic epileptic phase and between 1.5 and 13.5 months after viral transduction. Results: In the DREADD group, dentate gyrus evoked potentials were inhibited after clozapine treatment. Only in DREADD‐expressing animals, clozapine reduced seizure frequency during the first 6 h postinjection. When administered repeatedly, seizures were suppressed during the entire day. Long‐term treatment with clozapine and olanzapine both resulted in significant seizure‐suppressing effects for multiple days. Histological analysis revealed DREADD expression in both hippocampi and some cortical regions. However, lesions were also detected at the site of vector injection. Significance: This study shows that inhibition of the hippocampus using chemogenetics results in potent seizure‐suppressing effects in the intraperitoneal kainic acid rat model, even 1 year after viral transduction. Despite a need for further optimization, chemogenetic neuromodulation represents a promising treatment prospect for temporal lobe epilepsy. [ABSTRACT FROM AUTHOR]

New psychoactive substances continue to appear on the drug market. Until recently, new synthetic opioids, which are among the most dangerous new psychoactive substances, primarily encompassed analogs of the potent analgesic fentanyl. Lately, also other new synthetic opioids have increasingly started to surface. This is the first report on the identification and full chemical characterization of brorphine, a novel potent synthetic opioid with a piperidine benzimidazolone structure. A powder, identified as brorphine, was obtained from a patient seeking medical help for detoxification. Brorphine was also found in a serum sample of the patient. Liquid chromatography–high-resolution mass spectrometry (LC–HRMS) identified an exact mass of m/z 400.1020 and 402.1005 for the compound, corresponding to both bromine isotopes. Further chemical characterization was performed by gas chromatography–mass spectrometry, liquid chromatography–diode array detection and Fourier-transform infrared spectroscopy analyses. Finally, the structure was confirmed by performing 1H-NMR and 13C-NMR spectroscopy. In vitro biological activity of brorphine was determined by a cell-based µ-opioid receptor activation assay, resulting in an EC 50 of 30.9 nM (13.5 ng/mL) and an E max of 209% relative to hydromorphone, confirming the high potency and efficacy of this compound. In a serum sample of the patient, brorphine and a hydroxy-metabolite were found using the LC–HRMS screening method. The presence of opioid activity in the serum was also confirmed via the activity-based opioid screening assay. The occurrence of brorphine is yet another example of how the illicit drug market is continuously evolving in an attempt to escape international legislation. Its high potency poses a serious and imminent health threat for any user. [ABSTRACT FROM AUTHOR]

Abstract Objectives The antibiotic teicoplanin, used for the treatment of infections caused by Gram-positive bacteria, is highly bound to plasma proteins (percentage protein binding, %PB, around 90%) and therapeutic plasma levels of total teicoplanin are 10–100 mg/L. Because of the low free concentrations (i.e. <1–10 mg/L), current immunoassays are not able to quantify free teicoplanin concentrations, although they might be more relevant in therapeutic drug monitoring than total concentrations. Design and methods In this study, an ultra-high performance liquid chromatography – high resolution mass spectrometry (UHPLC-HRMS) method for the quantification of total and free teicoplanin in K 2 EDTA plasma samples was developed and validated. Furthermore, %PB obtained by ultrafiltration was compared with that obtained by equilibrium dialysis using spiked samples from healthy subjects. Analytes were separated using a phenylhexyl column, gradient mobile phase analysis was used, total run time was 4.5 min and teicoplanin was detected by orbitrap MS. Results The precision and accuracy were below 15% and within ±15%, respectively and teicoplanin was found to be stable for at least 14 days in plasma at 4 °C. The %PB of teicoplanin in spiked plasma from healthy subjects as obtained by ultrafiltration (94.1 ± 1.3%) was in good agreement with that obtained by equilibrium dialysis (93.6 ± 0.4%), whereas mean %PB of teicoplanin in samples from infected patients who received the antibiotic was 87.7 ± 4.2% (range: 79.6–95.4%). Conclusion A novel highly sensitive UHPLC-HRMS method was developed and validated for the quantification of total and free teicoplanin in human K 2 EDTA plasma samples. Amongst others, this method is suitable for therapeutic drug monitoring. [ABSTRACT FROM AUTHOR]

Background: Several population pharmacokinetic (PopPK) models for meropenem dosing in ICU patients are available. It is not known to what extent these models can predict meropenem concentrations in an independent validation dataset when meropenem is infused continuously.Patients and methods: A PopPK model was developed with concentration-time data collected from routine care of 21 ICU patients (38 samples) receiving continuous infusion meropenem. The predictability of this model and seven other published PopPK models was studied using an independent dataset that consisted of 47 ICU patients (161 samples) receiving continuous infusion meropenem. A statistical comparison of imprecision (mean square prediction error) and bias (mean prediction error) was conducted.Results: A one-compartment model with linear elimination and creatinine clearance as a covariate of clearance best described our data. The mean ± SD parameter estimate for CL was 9.89 ± 3.71 L/h. The estimated volume of distribution was 48.1 L. The different PopPK models showed a bias in predicting serum concentrations from the validation dataset that ranged from -8.76 to 7.06 mg/L. Imprecision ranged from 9.90 to 42.1 mg/L.Conclusions: Published PopPK models for meropenem vary considerably in their predictive performance when validated in an external dataset of ICU patients receiving continuous infusion meropenem. It is necessary to validate PopPK models in a target population before implementing them in a therapeutic drug monitoring program aimed at optimizing meropenem dosing. [ABSTRACT FROM AUTHOR]

Background Several population pharmacokinetic (PopPK) models for meropenem dosing in ICU patients are available. It is not known to what extent these models can predict meropenem concentrations in an independent validation dataset when meropenem is infused continuously. Patients and methods A PopPK model was developed with concentration–time data collected from routine care of 21 ICU patients (38 samples) receiving continuous infusion meropenem. The predictability of this model and seven other published PopPK models was studied using an independent dataset that consisted of 47 ICU patients (161 samples) receiving continuous infusion meropenem. A statistical comparison of imprecision (mean square prediction error) and bias (mean prediction error) was conducted. Results A one-compartment model with linear elimination and creatinine clearance as a covariate of clearance best described our data. The mean ± SD parameter estimate for CL was 9.89 ± 3.71 L/h. The estimated volume of distribution was 48.1 L. The different PopPK models showed a bias in predicting serum concentrations from the validation dataset that ranged from −8.76 to 7.06 mg/L. Imprecision ranged from 9.90 to 42.1 mg/L. Conclusions Published PopPK models for meropenem vary considerably in their predictive performance when validated in an external dataset of ICU patients receiving continuous infusion meropenem. It is necessary to validate PopPK models in a target population before implementing them in a therapeutic drug monitoring program aimed at optimizing meropenem dosing. [ABSTRACT FROM AUTHOR]

Background: Harmonization of units is an important step to improve the comparability of clinical chemistry results, but few examples exist of successful harmonization efforts. We present the results of a pragmatic approach that was implemented in Belgium from 2012. Methods: After a large consultation and information of stakeholders, preferred units were proposed for 140 assays, including the 23 immunoassays discussed in more detail here. The change occurred in two phases, first involving assays for which there was no change in the numerical result, then changes involving a change in numerical results. Laboratories were invited to participate in this harmonization on a voluntary basis. The project was based on a bottom-up approach, large consultation and the pragmatic choice of the proposed units, including conventional and SI units. Results: The large heterogeneity of units was drastically reduced; adoption of the preferred units increased from 3% (insulin) – 45% (HCG) to 70% (insulin) – 96% (LH and FSH). Adoption of the preferred units was higher if it involved no change in numerical values (90%) than when there was a change (76%). Conclusions: We believe that the harmonization effort has reached its goals. Without aiming at implementing SI units for all parameters, our strategy was successful with a large majority of the laboratories switching to the proposed units. Moreover, the harmonization program is still progressing, with additional laboratories converting to the consensus units. [ABSTRACT FROM AUTHOR]

Dosing recommendations for continuous infusion of piperacillin, a broad-spectrum beta-lactam antibiotic, are mainly guided by outputs from population pharmacokinetic models constructed with intermittent infusion data. However, the probability of target attainment in patients receiving piperacillin by continuous infusion may be overestimated when drug clearance estimates from population pharmacokinetic models based on intermittent infusion data are used, especially when higher doses (e.g. 16 g/24 h or more) are simulated. Therefore, the purpose of this study was to describe the population pharmacokinetics of piperacillin when infused continuously in critically ill patients. For this analysis, 270 plasma samples from 110 critically ill patients receiving piperacillin were available for population pharmacokinetic model building. A one-compartment model with linear clearance best described the concentration–time data. The mean ± standard deviation parameter estimates were 8.38 ± 9.91 L/h for drug clearance and 25.54 ± 3.65 L for volume of distribution. Creatinine clearance improved the model fit and was supported for inclusion as a covariate. In critically ill patients with renal clearance higher than 90 mL/min/1.73 m 2 , a high-dose continuous infusion of 24 g/24 h is insufficient to achieve adequate exposure (pharmacokinetic/pharmacodynamic target of 100% f T >4 x MIC ) against susceptible Pseudomonas aerginosa isolates (MIC ≤16 mg/L). These findings suggest that merely increasing the dose of piperacillin, even with continuous infusion, may not always result in adequate piperacillin exposure. This should be confirmed by evaluating piperacillin target attainment rates in critically ill patients exhibiting high renal clearance. [ABSTRACT FROM AUTHOR]

Objectives: Antibiotic therapy is of vital importance for the control of infectious exacerbations in cystic fibrosis (CF) patients. However, very little is known regarding the fraction of systemically administered antibiotics reaching the lower respiratory tract secretions. We developed and validated a method to measure the concentrations of piperacillin, ceftazidime, meropenem and aztreonam in CF sputum, and present the validation data.Methods: Ultra-performance LC coupled to tandem MS was used. A single sample can be measured in 2.5 min with multiple reaction monitoring in positive electrospray ionization mode. Deuterated internal standards were used and a concentration range of 0.7-160 mg/L was covered. The method was validated according to the EMA guideline on analytical method validation.Results: The boundaries within which a reliable measurement in CF sputum can be performed were determined. A few constraints are linked to the instability of the antibiotics in sputum. Piperacillin showed limited stability at room temperature and during freeze-thaw cycles. Autosampler instability was observed after 15 h for aztreonam at low concentrations.Conclusions: The method allows a reliable measurement of the selected antibiotics, if precautions are taken regarding the limited stability of piperacillin at room temperature. Due to freeze-thaw instability, piperacillin should always be analysed on the day of sampling. Quick review of the analytical data and reanalysis are needed as low concentrations of aztreonam are not stable in the autosampler. [ABSTRACT FROM AUTHOR]

Objectives: To characterize the population pharmacokinetics of piperacillin and tazobactam in critically ill infants and children, in order to develop an evidence-based dosing regimen.Patients and methods: This pharmacokinetic study enrolled patients admitted to the paediatric ICU for whom intravenous piperacillin/tazobactam (8:1 ratio) was indicated (75 mg/kg every 6 h based on piperacillin). Piperacillin/tazobactam concentrations were measured by an LC-MS/MS method. Pharmacokinetic data were analysed using non-linear mixed effects modelling.Results: Piperacillin and tazobactam blood samples were collected from 47 patients (median age 2.83 years; range 2 months to 15 years). Piperacillin and tazobactam disposition was best described by a two-compartment model that included allometric scaling and a maturation function to account for the effect of growth and age. Mean clearance estimates for piperacillin and tazobactam were 4.00 and 3.01 L/h for a child of 14 kg. Monte Carlo simulations showed that an intermittent infusion of 75 mg/kg (based on piperacillin) every 4 h over 2 h, 100 mg/kg every 4 h given over 1 h or a loading dose of 75 mg/kg followed by a continuous infusion of 300 mg/kg/24 h were the minimal requirements to achieve the therapeutic targets for piperacillin (60% f T >MIC >16 mg/L).Conclusions: Standard intermittent dosing regimens do not ensure optimal piperacillin/tazobactam exposure in critically ill patients, thereby risking treatment failure. The use of a loading dose followed by a continuous infusion is recommended for treatment of severe infections in children >2 months of age. [ABSTRACT FROM AUTHOR]

Objectives Δ 9 -Tetrahydrocannabinol (THC) can be measured in exhaled breath by using an aerosol particle collection device. The sampling procedure is simple, non-invasive and takes only 2–3 min. In the present study we measured the amount of THC in exhaled breath of cannabis users at specific time intervals up to 3 h after smoking one cannabis cigarette. Design and methods The breath concentration-effect relationship was studied by measuring the pulse rate and the pupil diameter to assess physiological changes. THC and the main metabolite 11-nor-9-carboxy-Δ 9 -tetrahydrocannabinol were analyzed in exhaled breath by a liquid chromatography-tandem mass spectrometry method. Thirteen subjects (9 males and 4 females, aged 23–24 years) participated. Five of those were using cannabis more frequently than monthly. Results THC was detected in most subjects already at baseline, concentrations increased following smoking and remained detectable for over 3 h (mean THC concentration in breath at 3 h: 1479 pg/sample). Pulse rate (p = 0.015) and pupil diameter (p = 0.044) were significantly altered up to 30 min after smoking. The detection window of cannabis in breath after smoking one cannabis cigarette in occasional and chronic smokers was at least 3 h. Only THC was detected, and not the metabolite. The THC concentration in exhaled breath was related to the physiological changes that occur over time. Conclusions Exhaled breath can be used to detect recent cannabis exposure. [ABSTRACT FROM AUTHOR]

Aim: To assess whether analysis of oral fluid can be used to identify individual drivers with drug concentrations in blood above 25ng/mL for amphetamine and methamphetamine, 10ng/mL for cocaine and 1.0ng/mL for tetrahydrocannabinol (THC), which are the cut-off concentrations used in the European DRUID Project, by calculating the diagnostic accuracies when using the analytical cut-off concentrations in oral fluid as well as for the optimal cut-off concentrations.Methods: Paired samples of whole blood and oral fluid collected with the Statsure SalivaSampler were obtained from 4080 drivers in four European countries and analysed for amphetamine, methamphetamine, cocaine and THC using GC-MS or LC-MS. The vast majority (89%) were random drivers not suspected of drug-impaired driving. Receiver-Operating Characteristic analysis was used to evaluate the analytical results.Results: The prevalence of drug findings above the cut-off concentrations in blood was 1.3% for amphetamine, 1.0% for methamphetamine, 0.6% for cocaine and 1.3% for THC. The cut-off concentrations in oral fluid that gave the highest diagnostic accuracy were for amphetamine 130ng/mL (accuracy 99.8%), methamphetamine 280ng/mL (accuracy 99.9%), cocaine 570ng/mL (accuracy 99.6%), and THC 38ng/mL (accuracy 98.3%). The proportion of false positives were 0.2%, 0.1%, 0.1% and 0.9%; and the proportion of false negatives were 0.1%, 0.0%, 0.3% and 0.8%, respectively, when using those cut-offs. The positive predictive values were 87.9%, 92.9%, 84.6% and 35.7% for amphetamine, methamphetamine, cocaine and THC, respectively.Conclusions: Analysis of concentrations of illicit drugs in oral fluid could not be used to accurately identify drivers with drugs concentrations above the selected cut-offs in blood in a cohort of drivers with low prevalence of drugs. [ABSTRACT FROM AUTHOR]

In some patient groups, including critically ill patients, the pharmacokinetics of β-lactam antibiotics may be profoundly disturbed due to pathophysiological changes in distribution and elimination. Therapeutic drug monitoring (TDM) is a strategy that may help to optimise dosing. The aim of this review was to identify and analyse the published literature on the methods used for β-lactam quantification in TDM programmes. Sixteen reports described methods for the simultaneous determination of three or more β-lactam antibiotics in plasma/serum. Measurement of these antibiotics, due to low frequency of usage relative to some other tests, is generally limited to in-house chromatographic methods coupled to ultraviolet or mass spectrometric detection. Although many published methods state they are fit for TDM, they are inconvenient because of intensive sample preparation and/or long run times. Ideally, methods used for routine TDM should have a short turnaround time (fast run-time and fast sample preparation), a low limit of quantification and a sufficiently high upper limit of quantification. The published assays included a median of 6 analytes [interquartile range (IQR) 4-10], with meropenem and piperacillin being the most frequently measured β-lactam antibiotics. The median run time was 8 min (IQR 5.9-21.3 min). There is also a growing number of methods measuring free concentrations. An assay that measures antibiotics without any sample preparation would be the next step towards real-time monitoring; no such method is currently available. [ABSTRACT FROM AUTHOR]

The article discusses a study which evaluated the efficacy of voriconazole (VRC) in treating fungal infections. Topics covered include the major determinants of variability of VRC plasma concentrations such as oral bioavailability and VRC pharmacokinetics, an overview of the analytical methods for measuring VRC in plasma including bioassays, and the linearity of the VRC assay.

There is an increasing interest in monitoring plasma concentrations of β-lactam antibiotics. The objective of this work was to develop and validate a fast ultra-performance liquid chromatographic method with tandem mass spectrometric detection (UPLC–MS/MS) for simultaneous quantification of amoxicillin, cefuroxime, ceftazidime, meropenem and piperacillin with minimal turn around time. Sample clean-up included protein precipitation with acetonitrile containing 5 deuterated internal standards, and subsequent dilution of the supernatant with water after centrifugation. Runtime was only 2.5 min. Chromatographic separation was performed on a Waters Acquity UPLC system using a BEH C 18 column (1.7 μm, 100 mm × 2.1 mm) applying a binary gradient elution of water and methanol both containing 0.1% formic acid and 2 mmol/L ammonium acetate on a Water TQD instrument in MRM mode. All compounds were detected in electrospray positive ion mode and could be quantified between 1 and 100 mg/L for amoxicillin and cefuroxime, between 0.5 and 80 mg/L for meropenem and ceftazidime, and between 1 and 150 mg/L for piperacillin. The method was validated in terms of precision, accuracy, linearity, matrix effect and recovery and has been compared to a previously published UPLC–MS/MS method. [ABSTRACT FROM AUTHOR]

Objectives To investigate the population pharmacokinetics of cefuroxime in critically ill patients. Methods In this observational pharmacokinetic study, multiple blood samples were taken over one dosing interval of intravenous cefuroxime. Blood samples were analysed using a validated ultra HPLC tandem mass spectrometry technique. Population pharmacokinetic analysis and dosing simulations were performed using non-linear mixed-effects modelling. Results One hundred and sixty blood samples were collected from 20 patients. CLCR ranged between 10 and 304 mL/min. A two-compartment model with between-subject variability on CL, V of the central compartment and V of the peripheral compartment described the data adequately. Twenty-four hour urinary CLCR was supported as a descriptor of drug CL. The population model for CL was CL = θ1 × CLCR/100, where θ1 is the typical cefuroxime CL in the population, which is 9.0 L/h. The mean V was 22.5 L. Dosing simulations showed failure to achieve the pharmacokinetic/pharmacodynamic target of 65% fT>MIC for an MIC of 8 mg/L with standard dosing regimens for patients with CLCR ≥50 mL/min. Conclusions Administration of standard doses by intermittent bolus is likely to result in underdosing for many critically ill patients. Continuous infusion of higher than normal doses after a loading dose is more likely to achieve pharmacokinetic/pharmacodynamic targets. However, even continuous infusion of high doses (up to 9 g per day) does not guarantee adequate levels for all patients with a CLCR of ≥300 mL/min if the MIC is 8 mg/L. [ABSTRACT FROM PUBLISHER]

Background Tacrolimus (TAC) is a post-transplantation immunosuppressant drug used in patients for whom careful monitoring of TAC concentration is essential. A new semi-automated immunoassay for TAC measurement, the Elecsys Tacrolimus assay, is available and has been assessed in a multi-center evaluation. Methods Residual whole blood samples from patients undergoing TAC therapy after organ transplant were used in assay evaluation at five clinical laboratories in Europe. Experiments included imprecision according to CLSI EP5-A2 (within-run and intermediate), functional sensitivity, linearity according to CLSI EP6-A, and recovery from external quality assessment scheme (EQAS) samples. The assay was compared to LC-MS/MS used routinely at each investigational site, and to the Abbott Architect immunoassay. Results Linearity from 0.5 to 40μg/L was observed and functional sensitivity of 0.3μg/L (CV↜20%) was determined. Within-run imprecision was ↜ 5.1% on cobas e 602 (5.1% at 1.5μg/L) and ↜ 8.9% (8.9% at 0.8μg/L) on cobas e 411. The intermediate imprecision for TAC concentrations ≥ 6.8μg/L was ↜ 6.5%. At lower therapeutic concentrations (to 1.5μg/L) it was consistently ↜ 10%. Deming regression analysis of method comparison to LC-MS/MS yielded slopes of 1.07 (95%CI: 1.05/1.10) for heart transplant samples, 1.13 (95%CI: 1.09/1.16) for kidney, and 1.05 (95%CI: 1.02/1.08) for lung transplant samples. Conclusions The Elecsys Tacrolimus assay has good linearity, functional sensitivity and intermediate imprecision and is comparable to LC-MS/MS methods. The over-all performance of ECLIA demonstrates a modern generation TAC assay that meets the demands of monitoring drug concentrations in current immunosuppressive regimens. [ABSTRACT FROM AUTHOR]

Abstract: Piperacillin plasma concentrations are known to vary between critically ill patients. However, there are no comprehensive data on the variability of antibiotic concentrations within the same patient. The purpose of this study was to investigate the adequacy of dosing during an entire 7-day antibiotic course and to investigate the variability in antibiotic trough concentrations both between patients and within the same patient. Piperacillin trough concentrations were measured daily in critically ill patients with normal renal function. The drug assay was performed using UPLC–MS/MS. The pharmacokinetic/pharmacodynamic target was 100% fT>MIC of the Pseudomonas aeruginosa EUCAST breakpoint. Within- and between-patient variability were calculated as percent coefficient of variation (CV). Eleven patients treated for pneumonia were included in this nested prospective observational cohort study. The median (range) age was 67 (18–79) years, weight was 75 (57–90)kg and BMI was 23.5 (22.3–26.4). The median (range) creatinine clearance on Day 1 of antibiotic treatment was 102 (62–154)mL/min. Trough concentrations were variable, ranging from 4.9mg/L to 98.0mg/L. A median CV of 40% for within-patient variability and 57% for between-patient variability was found. Within-patient variability was inversely correlated with SOFA score (R =0.65, P =0.027) and APACHE II score on admission (R =0.73, P =0.009). In conclusion, piperacillin concentrations varied widely both between patients and within the same patient. Within-patient variability was inversely correlated with disease severity. Consistent dosing of piperacillin/tazobactam does not result in consistent piperacillin concentrations throughout the entire treatment period. [Copyright &y& Elsevier]

Oral fluid is an easily available specimen for studying drug use in a cohort or population. The prevalence of drugs in samples of oral fluid is the same as the prevalence in blood if using equivalent cutoff concentrations. The cutoffs in oral fluid may be higher or lower than that in blood in accordance with the median oral fluid-to-blood (OF/B) concentration ratio, but it is also influenced by the skewness of the distribution of OF/B ratios. The aim of this study was to determine formulae for the estimation of equivalent cutoff concentrations in oral fluid and blood for 12 commonly used illegal and medicinal psychoactive drugs when oral fluid was collected with Statsure Saliva·SamplerTM. Paired samples from 4,080 persons were collected and analyzed with chromatographic methods and mass spectroscopic detection. Regression formulae for the concentrations corresponding to selected percentiles in oral fluid versus the same concentration percentiles in blood were determined. The accuracy when multiplying the cutoff thresholds in blood with the average and median OF/B ratios to estimate equivalent cutoffs in oral fluid was also investigated. Prevalence regression gave the most accurate results. The regression formulae can be used to estimate equivalent cutoff concentrations in oral fluid and blood. [ABSTRACT FROM AUTHOR]

The article examines the analytical characteristics of the ARK methotrexate (MTX) immunoassay for the quantitative examination of MTX in human plasma on automated clinical chemistry analyzers. Topics discussed include the purpose of the antifolate MTX, results of the accuracy evaluation of the immunoassay and functional sensitivity and linearity of the ARK MTX immunoassay. Also discussed is the potential of the ARK Assay as an alternative to fluorescence polarization immunoassay (FPIA).

Objectives The objective of this study was to investigate the population pharmacokinetics and pharmacodynamics of amoxicillin and clavulanic acid in critically ill patients. Methods In this observational pharmacokinetic study, multiple blood samples were taken over one dosing interval of intravenous amoxicillin/clavulanic acid (1000/200 mg). Blood samples were analysed using a validated ultra HPLC–tandem mass spectrometry technique. Population pharmacokinetic analysis and dosing simulations were performed using non-linear mixed-effects modelling. Results One-hundred-and-four blood samples were collected from 13 patients. For both amoxicillin and clavulanic acid, a two-compartment model with between-subject variability for both the clearance and the volume of distribution of the central compartment described the data adequately. For both compounds, 24 h urinary creatinine clearance was supported as a descriptor of drug clearance. The mean clearance of amoxicillin was 10.0 L/h and the mean volume of distribution was 27.4 L. For clavulanic acid, the mean clearance was 6.8 L/h and the mean volume of distribution was 19.2 L. Dosing simulations for amoxicillin supported the use of standard dosing regimens (30 min infusion of 1 g four-times daily or 2 g three-times daily) for most patients when using a target MIC of 8 mg/L and a pharmacodynamic target of 50% fT>MIC, except for those with a creatinine clearance >190 mL/min. Dosing simulations for clavulanic acid showed little accumulation when high doses were administered to patients with high creatinine clearance. Conclusions Although vast pharmacokinetic variability exists for both amoxicillin and clavulanic acid in intensive care unit patients, current dosing regiments are appropriate for most patients, except those with very high creatinine clearance. [ABSTRACT FROM PUBLISHER]

Abstract: Between 2006 and 2010, six population based case–control studies were conducted as part of the European research-project DRUID (DRiving Under the Influence of Drugs, alcohol and medicines). The aim of these case–control studies was to calculate odds ratios indicating the relative risk of serious injury in car crashes. The calculated odds ratios in these studies showed large variations, despite the use of uniform guidelines for the study designs. The main objective of the present article is to provide insight into the presence of random and systematic errors in the six DRUID case–control studies. Relevant information was gathered from the DRUID-reports for eleven indicators for errors. The results showed that differences between the odds ratios in the DRUID case–control studies may indeed be (partially) explained by random and systematic errors. Selection bias and errors due to small sample sizes and cell counts were the most frequently observed errors in the six DRUID case–control studies. Therefore, it is recommended that epidemiological studies that assess the risk of psychoactive substances in traffic pay specific attention to avoid these potential sources of random and systematic errors. The list of indicators that was identified in this study is useful both as guidance for systematic reviews and meta-analyses and for future epidemiological studies in the field of driving under the influence to minimize sources of errors already at the start of the study. [Copyright &y& Elsevier]

Abstract: There is an increasing interest in monitoring plasma concentrations of β-lactam antibiotics. The objective of this work was to develop and validate a rapid ultra-performance liquid chromatographic method with tandem mass spectrometric detection (UPLC-MS/MS) for simultaneous quantification of amoxicillin, ampicillin, cefuroxime, cefazolin, ceftazidime, meropenem, piperacillin, clavulanic acid and tazobactam. Sample clean-up included protein precipitation with acetonitrile and back-extraction of acetonitrile with dichloromethane. Six deuterated β-lactam antibiotics were used as internal standards. Chromatographic separation was performed on a Waters ACQUITY UPLC system using a BEH C18 column (1.7μm, 100mm×2.1mm) applying a binary gradient elution of water and acetonitrile both containing 0.1% formic acid. The total run time was 5.5min. The developed method was validated in terms of precision, accuracy, linearity, matrix effect and recovery. The assay has now been successfully used to determine concentrations of amoxicillin/clavulanic acid, cefuroxime and meropenem in plasma samples from intensive care patients. [Copyright &y& Elsevier]

Objective. The purpose of this study was to compare the prevalence of psychoactive substances in general traffic in The Netherlands and Belgium. Method: Randomly selected car drivers and drivers of small vans in six police regions in The Netherlands and five police regions in Belgium were included between January 2007 and August 2009. Blood and oral fluid samples were analyzed for 23 substances, including ethanol (alcohol), by means of ultra performance liquid chromatography--tandem mass spectrometry or gas chromatography--mass spectrometry analysis. Samples were weighted according to the distribution of traffic over eight 6-hour periods. Substance groups were categorized in five mutually exclusive classes: single alcohol use, single illicit drug use, single medicinal drugs use, multiple drug use (including drugs from two or more separate substance groups but excluding alcohol), and drug use (either single or multiple) in combination with alcohol. Results: In total, 7,771 drivers (4,822 in The Netherlands and 2,949 in Belgium) were included in the study. In Belgium, the prevalence of single alcohol (6.4%) and single medicinal drugs (3.0%) was much higher than in The Netherlands (2.2% and 0.6%, respectively), whereas the single illicit drugs were more common in Dutch traffic (2.2%) than in Belgian traffic (0.6%). Compared with the estimated prevalence of psychoactive substances in the general driving public in Europe, the prevalence in Belgium (10.7%) was greater than the European average (7.4%), and the prevalence in The Netherlands was below the European average (5.5%). Conclusions: The observed prevalence of psychoactive substances varies largely between The Netherlands and Belgium. Probable reasons for the differences are the higher level of alcohol enforcement in The Netherlands and nonresponse bias in the Belgian study (for illicit drugs in particular). Furthermore, cultural differences and variances in prescription policy could also be influential. (J. Stud. Alcohol Drugs, 73, 951-960, 2012) [ABSTRACT FROM AUTHOR]

Abstract: Study objective: To compare the prevalence of alcohol and (il)licit drugs in seriously injured drivers in Belgium (BE) and the Netherlands (NL). Methods: Injured car and van drivers admitted to the emergency departments of five hospitals in Belgium and three in the Netherlands from January 2008 to May 2010 were included. Blood samples were taken and analysed for ethanol (with an enzymatic method) and 22 other psychoactive substances (UPLC–MS/MS or GC–MS). Results: In total 535 injured drivers were included in the study (BE: 348; NL: 187). More drivers were found positive for alcohol and drugs in Belgium (52.6%) than in the Netherlands (33.9%). Alcohol (≥0.1g/L) was the most prevalent substance in both countries (BE: 42.5%; NL: 29.6%). A similar prevalence was found for amphetamine (BE: 2.6%; NL: 2.2%) and cocaine (BE: 2.3%; NL: 2.1%). In the Netherlands almost no positive findings for cannabis were recorded (0.5%). No driver tested positive for benzodiazepines in the Netherlands compared to 7.3% in Belgium. More injured drivers tested positive for Z-drugs (BE: 1.8%; NL: 0.5%) and medicinal opioids (BE: 3.3%; NL: 0.5%) in Belgium. Conclusions: The prevalence of alcohol in seriously injured drivers was 12% higher found in Belgium than in the Netherlands. The prevalence of drugs was similar in both countries except for THC and medicinal drugs, particularly benzodiazepines, with a much higher prevalence in Belgium. In comparison to previous survey there were differences in the prevalence of THC, benzodiazepines and combinations of drugs. Possible explanations are the different matrix used, a bias in study population, or in case of illicit opiates and benzodiazepines a different consumption pattern in the two countries. Alcohol is still the most prevalent substance among the injured driver population and this increased the last 15 years. [Copyright &y& Elsevier]

The article presents a study which compares the number of drivers in Belgium who had consumed drug above the legal cutoffs for driving under influence of illicit substances in oral fluids and blood. It mentions that the samples were analyzed by ultra-performance liquid chromatography-tandem mass spectrometry along with gas chromatography-tandem mass spectrometry. It concludes more positive results were obtained based on oral fluid analysis as compared to blood analysis.

Background: Mycophenolic acid (MPA) is an immunosuppressant for which therapeutic drug monitoring (TDM) is performed for optimal prophylaxis and avoidance of toxicity in transplant patients. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is ideally suited for TDM of MPA. There have been several method comparisons of the Roche Total MPA assay, but none have been performed with respect to liver transplant patients. Methods: We validated the Roche Total MPA assay on the Cobas Integra 400 and Cobas 6000 and compared it to a validated LC-MS/MS (API 2000™) method. Fifty-five EDTA plasma samples from liver transplant patients were measured with the Roche assay on these platforms and compared to the LC-MS/MS results. Results: Validation of the LC-MS/MS, Cobas Integra 400 and 6000 was performed with good results. The LC-MS/MS/Integra 400/Cobas 6000 were linear up to 30, 15 and 17 mg/L, respectively. Imprecision was <10% for LC-MS/MS and <7% for the Roche assay on both platforms. The samples showed good agreement with LC-MS/MS. Passing-Bablok regression analysis showed Cobas Integra (mg/L)=1.02×LC-MS/MS (mg/L)-0.50 and Cobas 6000 (mg/L)=0.98×LC-MS/MS-0.47. Conclusions: The Roche Total Mycophenolic Acid-assay is suitable for measuring total MPA in plasma from liver transplant patients and is a good alternative for LC-MS/MS. [ABSTRACT FROM AUTHOR]

Case reports mention a sudden awakening from GHB-associated coma but do not specify its time course. The aim of the present case series was to investigate the time course of the awakening from GHB intoxication and the relationship to plasma concentrations of GHB and the presence of other drugs. Unconscious (GCS ≤8) participants at six large rave parties who were treated at medical stations were included. Serial blood samples were taken every 10 to 30 minutes for toxicological analysis. At the same time-points, the depth of coma was scored with the Glasgow Coma Score (GCS). Fifteen out of 21 unconscious patients proved to be positive for GHB. Fourteen of these had ingested one or more other drugs. The median GHB plasma concentration upon arrival in the medical station was 212 μg/ml (range 112 to 430 μg/ml). In 10 patients the GCS was scored more than twice, allowing study of the time course. The GCS of these patients remained ≤8 for a median time of 90 minutes (range 30 to 105 minutes). The duration of the transition between GCS of ≤8 and ≥12 was 30 minutes (range 10 to 50 minutes). A subgroup of five patients had a GCS of 3 upon arrival and remained at 3 for a median time of 60 minutes (range 30 to 110 minutes), while the median time for the transition between the last point with GCS 3 and the first with GCS 15 was 30 minutes (range 20 to 60 minutes). This case series illustrates that patients with GHB intoxications remain in a deep coma for a relatively long period of time, after which they awaken over about 30 minutes. This awakening is accompanied by a small change in GHB concentrations. A confounding factor in these observations is co-ingested illicit drugs. [ABSTRACT FROM AUTHOR]

We report three patients with anticholinergic poisoning caused by the substitution of hyoscine hydrobromide for hyoscine butylbromide in preparations compounded by two different pharmacists. The patients took the preparations for gastrointestinal discomfort and presented with altered mental status, tachycardia, facial flushing, dilated pupils, and dry skin shortly after the ingestion. In one patient the intoxication was initially not recognized and he was treated as suffering from an acute cerebrovascular accident. Two patients experienced long-lasting effects such as decreased ability to concentrate, memory disturbances, tremor, and photo- and phonophobia. It was obviously impossible to elucidate the exact nature of the relationship between the intoxication and these long-lasting complaints. Information from the Belgian poison control center revealed that cases of substitution error with hyoscine hydrobromide are not unique. The Belgian authorities issued a warning to all pharmacists. [ABSTRACT FROM AUTHOR]