Sensitive recognition of ractopamine using GQDs-DPA as organic fluorescent probe.

A novel spectrofluorimetric sensing platform was designed for Ractopamine measurement in aqueous and plasma samples. d-penicillamine functionalized graphene quantum dots (DPA-GQDs) was utilized as a fluorescence probe, which was synthesized through the pyrolysis of citric acid in the presence of DPA. This one-pot down-top strategy causes to high-yield controllable synthesis method. The reaction time and probe concentration were optimized. Then, the fluorescence intensity of aqueous samples containing different Ractopamine concentrations and 500 ppm DPA-GQDs were measured at 25°C with an excitation wavelength of 274 nm. The sensing platform was also applied to detect Ractopamine in untreated plasma samples. The fluorescence spectroscopy technique responses indicated a linear relationship between the peak fluorescence intensity and ractopamine concentration in the range of 0.25-15 ppm with low limit of quantification of 0.25 ppm was for aqueous and plasma samples, respectively.

Clinical and Toxicological Profile of NBOMes: A Systematic Review.

BACKGROUND: NBOMes are a new class of potent hallucinogens widely present in illicit drugs. Little is known about this class of drugs, regarding its detection and clinical manifestations of intoxication. OBJECTIVE: This study aims to enhance care involving NBOMes by reviewing the literature on their clinical manifestations and laboratorydetection. METHODS: A systematic review was performed on the clinical manifestations and laboratory tests of NBOMEs ingestion. Embase, Pubmed, PsycINFO, and Cochrane databases were employed in this analysis. RESULTS: Forty-five articles met the inclusion criteria out of the 2814 nonduplicated studies on the theme. Seventy case reports of intoxication were found in the analyzed articles (64.3% were men and 11.4% were women, mean age of 22.5). The technique most employed for NBOMes identification was chromatography of blood, urine, and oral fluids. Moreover, the studies identified 13 chemical structures differentfrom the NBOMes on their toxicological analyses.According to these studies, most of these drugs were ingested orally-nasal use was the second preferred administration route, followed by intravenous administration. CONCLUSION: Better identification of the clinicalmanifestations and laboratory profile of NBOMes is crucial to the recognition of intoxication as well as to its effective treatment.

A multidimensional 1H NMR lipidomics workflow to address chemical food safety issues.

INTRODUCTION: Although it is still at a very early stage compared to its mass spectrometry (MS) counterpart, proton nuclear magnetic resonance (NMR) lipidomics is worth being investigated as an original and complementary solution for lipidomics. Dedicated sample preparation protocols and adapted data acquisition methods have to be developed to set up an NMR lipidomics workflow; in particular, the considerable overlap observed for lipid signals on 1D spectra may hamper its applicability. OBJECTIVES: The study describes the development of a complete proton NMR lipidomics workflow for application to serum fingerprinting. It includes the assessment of fast 2D NMR strategies, which, besides reducing signal overlap by spreading the signals along a second dimension, offer compatibility with the high-throughput requirements of food quality characterization. METHOD: The robustness of the developed sample preparation protocol is assessed in terms of repeatability and ability to provide informative fingerprints; further, different NMR acquisition schemes-including classical 1D, fast 2D based on non-uniform sampling or ultrafast schemes-are evaluated and compared. Finally, as a proof of concept, the developed workflow is applied to characterize lipid profiles disruption in serum from ß-agonists diet fed pigs. RESULTS: Our results show the ability of the workflow to discriminate efficiently sample groups based on their lipidic profile, while using fast 2D NMR methods in an automated acquisition framework. CONCLUSION: This work demonstrates the potential of fast multidimensional 1H NMR-suited with an appropriate sample preparation-for lipidomics fingerprinting as well as its applicability to address chemical food safety issues.

Aggregated silver nanoparticles based surface-enhanced Raman scattering enzyme-linked immunosorbent assay for ultrasensitive detection of protein biomarkers and small molecules.

Lowering the detection limit is critical to the design of bioassays required for medical diagnostics, environmental monitoring, and food safety regulations. The current sensitivity of standard color-based analyte detection limits the further use of enzyme-linked immunosorbent assays (ELISAs) in research and clinical diagnoses. Here, we demonstrate a novel method that uses the Raman signal as the signal-generating system of an ELISA and combines surface-enhanced Raman scattering (SERS) with silver nanoparticles aggregation for ultrasensitive analyte detection. The enzyme label of the ELISA controls the dissolution of Raman reporter-labeled silver nanoparticles through hydrogen peroxide and generates a strong Raman signal when the analyte is present. Using this assay, prostate-specific antigen (PSA) and the adrenal stimulant ractopamine (Rac) were detected in whole serum and urine at the ultralow concentrations of 10(-9) and 10(-6) ng/mL, respectively. The methodology proposed here could potentially be applied to other molecules detection as well as PSA and Rac.

Driving under the influence of synthetic phenethylamines: a case series.

New psychoactive drugs, so-called legal highs, have gained more and more popularity during the last years. One of the most important groups of these legal high substances are the synthetic phenethylamines that share a common phenethylamine moiety. Based on certain structural characteristics, these synthetic phenethylamines can be divided into further subclasses, among which the synthetic cathinones ('bath salts') are particularly noteworthy. Synthetic cathinones are characterized by an additional carbonyl group attached at the beta position on the amino alkyl chain. Consumption of synthetic phenethylamines can lead to impairments similar to those observed after the use of, for instance, amphetamine or 3,4-methylenedioxy-N-methylamphetamine (MDMA, 'ecstasy'). These impairments include diverse neurological and psychological symptoms which can affect a safe driving behaviour. Although several reports on clinical symptoms and poisonings due to these substances have been published, most of these publications do not contain any analytical data. Additionally, there is still a lack of information concerning pharmacological and toxicological effects of these rather new psychoactive substances. In particular, the knowledge of the impact on the ability to drive following consumption of synthetic phenethylamines is relevant for the police as well as for forensic toxicologists. In this publication, several cases of individuals driving under the influence (DUI) of synthetic phenethylamines (4-fluoroamphetamine, mephedrone (4-methylmethcathinone, 4-MMC), 2-DPMP (desoxypipradol), methylenedioxypyrovalerone (MDPV), benzedrone, N-ethylamphetamine (etilamfetamine), 3-methylmethcathinone (3-MMC)) are presented, focusing on analytical results and signs of impairment.

A data-independent acquisition workflow for qualitative screening of new psychoactive substances in biological samples.

Identification of new psychoactive substances (NPS) is challenging. Developing targeted methods for their analysis can be difficult and costly due to their impermanence on the drug scene. Accurate-mass mass spectrometry (AMMS) using a quadrupole time-of-flight (QTOF) analyzer can be useful for wide-scope screening since it provides sensitive, full-spectrum MS data. Our article presents a qualitative screening workflow based on data-independent acquisition mode (all-ions MS/MS) on liquid chromatography (LC) coupled to QTOFMS for the detection and identification of NPS in biological matrices. The workflow combines and structures fundamentals of target and suspect screening data processing techniques in a structured algorithm. This allows the detection and tentative identification of NPS and their metabolites. We have applied the workflow to two actual case studies involving drug intoxications where we detected and confirmed the parent compounds ketamine, 25B-NBOMe, 25C-NBOMe, and several predicted phase I and II metabolites not previously reported in urine and serum samples. The screening workflow demonstrates the added value for the detection and identification of NPS in biological matrices.

Pathological findings in 2 cases of fatal 25I-NBOMe toxicity.

The research compound 25I-NBOMe, also known as CIMBI-5 or INBMeO, was created in academic laboratories as a potent serotonin 2A receptor agonist. Because of its high affinity and ambiguous legal status, recreational drug enthusiasts have used this compound as a powerful alternative to other hallucinogenic drugs such as lysergic acid diethylamide. We report 2 deaths after 25I-NBOMe ingestion by decedents who attended separate "rave" parties. The first case involved a 21-year-old male who admitted taking "acid" to his friend. A sudden violent rage caused him to flail about, and he subsequently became unresponsive. The postmortem examination revealed numerous external injuries that were consistent with physical aggression. The second case involved a 15-year-old female who was socializing outside a rave party, became ill, and rapidly deteriorated as her friend transported her to the hospital. The postmortem assessment was similar to the first case in that external contusions featured prominently. Comprehensive toxicology screens in both cases revealed only evidence of marijuana use. A deeper analysis using time-of-flight mass spectrometry revealed the presence of 25I-NBOMe, which was further confirmed by tandem-mass spectrometry. The behavior and injuries in these cases reveal a consistent pattern preceding fatal 25I-NBOMe toxicity.

The development of an indirect competitive immunomagnetic-proximity ligation assay for small-molecule detection.

The development of an indirect competitive immunomagnetic-proximity ligation assay (ICIPLA), which is a novel method for detecting small molecules, is described in this report. Free small molecules in samples can be detected using a proximity ligation assay (PLA); the detection is based on the proximity effect caused by a high concentration of small molecule-BSA conjugates bound to streptavidin magnetic beads. As an indirect format competitive immunoassay, the ICIPLA method has the advantage in that the quantity of monoclonal antibody (mAb) used for small-molecule detection is 8-fold lower than that required for the competitive immunomagnetic-proximity ligation assay (CIPLA) described in our previous work. Small molecules can be detected using a single monoclonal antibody, and the PLA method can be used to amplify high-performance signals. In this work, the small molecular compound ractopamine (RAC) was selected as a target for ICIPLA. The limit of detection (LOD) was 0.01 ng ml(-1), and the method exhibited a broad dynamic range of up to six orders of magnitude. We also employed the ICIPLA method to detect RAC in serum, urine, and muscle extracts; the results indicated that the LOD and dynamic range were not altered. The cross-reactivity studies showed that the cross-reactivity values for all RAC analogs were below 0.01%. These results suggest that ICIPLA is a sensitive, specific and practical method for small-molecule detection. This is the first report of the improved PLA technology for small-molecule detection by indirect competitive formats in the biological samples.

High-performance liquid chromatography tandem mass spectrometry method for the determination of 2CC-NBOMe and 25I-NBOMe in human serum.

2CC-NBOMe {4-chloro-2,5-dimethoxyphenethyl-N-[(2-methoxyphenyl) methyl] ethanamine} and 25I-NBOMe {2-(4-iodo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl) methyl] ethanamine} are of a class of N-benzyl phenethylamine derivatives whose synthesis was first reported in the scientific literature in 2011. Recent reports from 'personal drug experience websites' and in the popular press indicate these drugs are the latest in a series of designer 'Bath Salt' drugs of abuse. The presented high-performance liquid chromatography triple quadrupole mass spectrometry (HPLC/MS/MS) method was developed for the detection and quantification of 2CC-NBOMe and 25I-NBOMe in serum of intoxicated emergency department patients. The assay applies 2-​(2,​5-​dimethoxyphenyl)-​N-​(2-​methoxybenzyl) ethanamine (25H-NBOMe) as the internal standard. Samples were extracted using solid-phase extraction columns. The chromatographic separation was performed on a Luna 3 µ C8(2) 100 Å, 100 × 2.0 mm, column. Detection was accomplished by multiple-reaction monitoring via an electrospray ionization source operating in the positive ionization mode. The calibration curves were linear over the investigated concentration range, 30-2000 pg/mL, with a lower limit of detection of 10 pg/mL for both 2CC-NBOMe and 25I-NBOMe. The method proved suitable for serum clinical toxicology testing. Two severely intoxicated emergency department patients were determined to have serum concentrations of 250 and 2780 pg/mL of 25I-NBOMe using the presented method.

Ecto-5'-nucleotidase (CD73) attenuates allograft airway rejection through adenosine 2A receptor stimulation.

There are multiple drivers of leukocyte recruitment in lung allografts that contribute to lymphocytic bronchitis (LB) and bronchiolitis obliterans (BO). The innate mechanisms driving (or inhibiting) leukocyte trafficking to allografts remain incompletely understood. This study tested the hypothesis that CD73 (ecto-5'nucleotidase), an enzyme that catalyzes the conversion of AMP to adenosine, is a critical negative regulator of LB and BO. Implantation of tracheal allografts from wild type (WT) mice into CD73(-/-) recipients revealed a striking increase in airway luminal obliteration at 7 d (62 +/- 4% and 47 +/- 5% for CD73(-/-) and WT allograft recipients, respectively; p = 0.046). There was also a concordant increase in CD3(+) lymphocytic infiltration (523 +/- 41 cells and 313 +/- 43 cells for CD73(-/-) and WT allograft recipients, respectively; p = 0.013). Because real-time PCR revealed a 43-fold upregulation of mRNA for the adenosine A2A receptor (A2AR) in WT allografts compared with WT isografts (p = 0.032), additional experiments were performed to determine whether the protective effect of CD73 was due to generation of adenosine and its stimulation of the A2AR. Treatment of WT recipients with an A2AR agonist significantly reduced CD3(+) lymphocyte infiltration and airway luminal obliteration; similar treatment of CD73(-/-) recipients rescued them from LB and airway obliteration. These data implicate CD73 acting through adenosine generation and its stimulation of the A2AR as a critical negative modulator of lymphocyte recruitment into airway allografts. The CD73/adenosine axis might be a new therapeutic target to prevent BO.

Fiber-based liquid-phase micro-extraction of mebeverine enantiomers followed by chiral high-performance liquid chromatography analysis and its application to pharmacokinetics study in rat plasma.

The applicability of two-phase liquid-phase micro-extraction (LPME) in porous hollow polypropylene fiber for the sample preparation and the stereoselective pharmacokinetics of mebeverine (MEB) enantiomers (an antispasmodic drug) in rat after intramuscular administration were studied. Plasma was assayed for MEB enantiomer concentrations using stereospecific high-performance liquid chromatography with ultraviolet detection after a simple, inexpensive, and efficient preconcentration and clean-up hollow fiber-based LPME. Under optimized micro-extraction conditions, MEB enantiomers were extracted with 25 µl of 1-octanol within a lumen of a hollow fiber from 0.5 ml of plasma previously diluted with 4.5 ml alkalized water (pH 10). The chromatographic analysis was carried out through chiral liquid chromatography using a DELTA S column and hexane-isopropyl alcohol (85:15 v/v) containing 0.2% triethylamine as mobile phase. The mean recoveries of (+)-MEB and (-)-MEB were 75.5% and 71.0%, respectively. The limit of detection (LOD) was 3.0 ng/ml with linear response over the concentration range of 10-2500 ng/ml with correlation coefficient higher than 0.993 for both enantiomers. The pharmacokinetic studies showed that the mean plasma levels of (+)-MEB were higher than those of (-)-MEB at almost all time points. Also, (+)-MEB exhibited greater t(max) (peak time in concentration-time profile), C(max) (peak concentration in concentration-time profile), t(1/2) (elimination half-life), and AUC(0-240 min) (area under the curve for concentration versus time) and smaller CL (clearance) and V(d) (apparent distribution volume) than its antipode. The obtained results implied that the absorption, distribution, and elimination of (-)-MEB were more rapid than those of (+)-MEB and there were stereoselective differences in pharmacokinetics.

Determination of New Psychoactive Substances in Whole Blood Using Microwave Fast Derivatization and Gas Chromatography/Mass Spectrometry.

The production and consumption of new psychoactive substances (NPSs) has been raising a major concern worldwide. Due to easy access and available information, many NPSs continue to be synthesized with an alarming increase of those available to purchase, despite all the control efforts created. A new analytical method was developed and validated to determine a group of phenethylamines and synthetic cathinones: cathinone, flephedrone, buphedrone, 4-MTA, α-PVP, methylone, 2C-P, ethylone, pentylone, MDPV and bromo-dragonFLY in whole blood. A mixed-mode solid phase extraction was applied to 250 µL of sample, and the extracts were derivatized with fast microwave technique before being analyzed by gas chromatography-mass spectrometry (GC-MS). The validation procedure followed the Scientific Working Group for Forensic Toxicology (SWGTOX) guidelines with parameters that included selectivity, linearity, limits of detection and quantification, intra- and inter-day precision and accuracy, recoveries and stability. The method presented linearity between 5 and 500 ng/mL for cathinone, buphedrone, 4-MTA, methylone, 2C-P and bromo-dragonFLY, 10-500 ng/mL for flephedrone, ethylone, pentylone and MDPV, and 40-500 ng/mL for α-PVP, with determination coefficients above 0.99 for all analytes. Recoveries ranged between 70.3% and 116.6%, and regarding intra- and inter-day precision, the relative mean errors were typically lower than 8.6%. The method was successfully applied to over 100 authentic samples from the Laboratory of Chemistry and Forensic Toxicology, Centre Branch, of the National Institute of Legal Medicine and Forensic Sciences, Portugal.

Multivariate optimization of mebeverine analysis using molecularly imprinted polymer electrochemical sensor based on silver nanoparticles.

Thin film of a moleculary imprinted polymer (MIP) based on electropolymerization method with sensitive and selective binding sites for mebeverine (MEB) was developed. This film was cast on pencil graphite electrode (PGE) by electrochemical polymerization in solution of pyrrole (PY) and template MEB via cyclic voltammetry scans and further electrodeposition of silver nanoparticles (AgNPs). Several parameters controlling the performance of the silver nano particles MIP pencil graphite electrode (AgNPs-MIP-PGE) including concentration of PY(mM) concentration of mebeverine (mM), number of cycles in electropolymerization, scan rate of CV process (mV. s-1), deposition time of AgNPs on to the MIP surface (s), stirring rate of loading solution (rpm), electrode loading time (min), pH of Britton-Robinson Buffer (BRB) solution were examined and optimized using multivariate optimization methods such as Plackett-Burman design (PBD) and central composite design (CCD). Two dynamic linear ranges of concentration for the MIP sensor were obtained as. 1 × 10 -8 to 1 × 10 -6 and 1 × 10 -5 to1 × 10-3 M with the limit of detection (LOD) of 8.6 × 10 -9M (S/N = 3). The proposed method was successfully intended for the determination of MEB in real samples (serum, capsule). The sensor was showed highly reproducible response (RSD 1.1%) to MEB concentration.

Development and validation of a UPLC-MS/MS analytical method for dofetilide in mouse plasma and urine, and its application to pharmacokinetic study.

A novel method using UPLC with tandem mass-spectrometric detection (UPLC-MS/MS) with positive electrospray ionization was developed for the detection of the antiarrhythmic drug, dofetilide, in mouse plasma and urine. Protein precipitation was performed on 10 µL of plasma and 2 µL of urine samples using dofetilide-D4 as an internal standard, and separation of the analyte was accomplished on a C18 analytical column with the flow of 0.40 mL/min. Subsequently, the method was successfully applied to determine the pharmacokinetic parameters of dofetilide following oral and intravenous administration. The calibration curve was linear over the selected concentration range (R2 ≥ 0.99), with a lower limit of quantitation of 5 ng/mL. The intra-day and inter-day precisions, and accuracies obtained from a 5-day validation ranged from 3.00 to 7.10%, 3.80-7.20%, and 93.0-106% for plasma, and 3.50-9.00%, 3.70-10.0%, 87.0-106% for urine, while the recovery of dofetilide was 93.7% and 97.4% in plasma and urine, respectively. The observed pharmacokinetic profiles revealed that absorption is the rate-limiting step in dofetilide distribution and elimination. Pharmacokinetic studies illustrate that the absolute bioavailability of dofetilide in the FVB strain mice is 34.5%. The current developed method allows for accurate and precise quantification of dofetilide in micro-volumes of plasma and urine, and was found to be suitable for supporting in vivo pharmacokinetic studies.

Skinfold thickness for rivastigmine patch application in Alzheimer's disease.

RATIONALE: Rivastigmine patches are used for patients with Alzheimer's disease (AD), but little is known about the serum concentration of rivastigmine and its metabolite or clinical adherence in relation to skinfold thickness after rivastigmine patch application. OBJECTIVES: The aim of this study was to examine the association between rivastigmine and NAP 226-90 serum concentration and skinfold thickness and to determine the appropriate skinfold thickness for the use of rivastigmine patch in patients with AD. METHODS: Patients with AD who continuously used rivastigmine patches (4.6 mg/24 h, 5 cm2) for more than 6 months were recruited. The serum concentrations of rivastigmine and NAP 226-90 were measured. Skinfold thickness was measured using a Lange Skinfold Caliper. RESULTS: In total, 91 patients with AD (40 men and 51 women) participated in this study on skinfold thickness measurement. Among them, 27 patients were examined for rivastigmine and NAP 226-90 serum concentrations, with mean concentrations of 1.0 ± 0.6 ng/mL and 3.6 ± 3.6 ng/mL, respectively. The skinfold thickness in the subscapular area was significantly negatively correlated with the NAP 226-90 serum concentration (Spearman's rank correlation coefficient = - 0.47, P = .01). In addition, patients with AD and a subscapular skinfold thickness of ≥25 mm exhibited a significantly high risk of decreased Mini-Mental Status Examination score and nonadherence to a rivastigmine patch (odds ratio 3.00; 95% confidence interval = 1.076-8.366, P = .03). CONCLUSIONS: Subscapular skinfold thickness was significantly negatively correlated with the NAP 226-90 serum concentration and may be considered an appropriate predictor of response and adherence to clinical application of a rivastigmine patch.

Cross-linked chitosan/thiolated graphene quantum dots as a biocompatible polysaccharide towards aptamer immobilization.

Chitosan has a number of commercial and possible biomedical uses. Chitosan as a polysaccharide is a bioactive polymer with a variety of applications due to its functional properties such as antibacterial activity, non-toxicity, ease of modification, and biodegradability. In this work, cross-linked chitosan/thiolated graphene quantum dot as a biocompatible polysaccharide was modified by gold nanoparticle and used for immobilization of ractopamine (RAC) aptamer. A highly specific DNA-aptamer (5'-SH-AAAAAGTGCGGGC-3'), selected to RAC was immobilized onto thiolated graphene quantum dots (GQDs)-chitosan (CS) nanocomposite modified by gold nanostructures (Au NSs) and used for quantification of RAC. Different shapes of gold nanostructures with various sizes from zero-dimensional nanoparticles to spherical structures were prepared by one-step template-assistant green electrodeposition method. Fully electrochemical methodology was used to prepare a new transducer on a glassy carbon surface which provided a high surface area to immobilize a high amount of the aptamer. Therefore, a label free electrochemical (EC) apta-assay for ultrasensitive detection of RAC was developed. A special immobilization media consisting of Au NSs/GQDs-CS/Cysteamine (CysA) was utilized to improve conductivity and performance of the biosensor. The RAC aptamer was attached on the Au NSs of the composite membrane via AuS bond. The fabrication process of the EC aptamer based assay was characterized by some electrochemical techniques. The peak currents obtained by differential pulse voltammetry decreased linearly with the increasing of RAC concentrations and the apta-assay responds approximately over a wide dynamic range of RAC concentration from 0.0044 fM to 19.55 µM. The low limit of quantification was 0.0044 fM.

The use of hair as a long-term indicator of low-dose ß2 agonist treatments in cattle: Implications for growth-promoting purposes monitoring.

The objective of this study was to assess the feasibility of using hair as a long-term indicator of cocktail (low-dose ß2 agonists) treatments in cattle. Six male Simmental cattle were treated with a mixture of low-dose clenbuterol, ractopamine, and salbutamol at dosages of 5.3, 223.3, and 50.0 µg/kg, respectively. The trial lasted for 112 days and included 28 days of treatment and 84 days of withdrawal. Plasma and urine samples taken during the treatment period contained the highest residues, with maximum concentrations of clenbuterol, ractopamine, and salbutamol in plasma of 1.49 ng/mL (Day 21), 43.78 (Day 14) ng/mL, and 8.07 ng/mL (Day 7), respectively, and in urine of 62.40 ng/mL (Day 28), 3995.77 ng/mL (Day 28), and 503.72 ng/mL (Day 1), respectively. On day 42 of withdrawal, the residues of all three ß2 agonists in plasma were below the limit of quantification (LOQ; 0.3 ng/mL for clenbuterol, and 0.5 ng/mL for ractopamine and salbutamol), and in urine samples were below or near the LOQ (the highest being ractopamine at 1.10 ng/mL). The highest concentrations of clenbuterol, ractopamine, and salbutamol in hair were 88.36, 1351.92, and 100.58 ng/g, respectively, on day 14 of withdrawal; and the residues were long-lasting, with 7.64, 28.55, and 8.77 ng/g, respectively, on day 84 of withdrawal. The results of this study demonstrate that hair could be utilized as a long-term indicator of the use of a combination of low-dose ß2 agonists in cattle, which could have implications for growth-promoting purposes monitoring.

Molecular modeling of a PAMAM-CGS21680 dendrimer bound to an A2A adenosine receptor homodimer.

The theoretical possibility of bivalent binding of a dendrimer, covalently appended with multiple copies of a small ligand, to a homodimer of a G protein-coupled receptor was investigated with a molecular modeling approach. A molecular model was constructed of a third generation (G3) poly(amidoamine) (PAMAM) dendrimer condensed with multiple copies of the potent A(2A) adenosine receptor agonist CGS21680. The dendrimer was bound to an A(2A) adenosine receptor homodimer. Two units of the nucleoside CGS21680 could occupy the A(2A) receptor homodimer simultaneously. The binding mode of CGS21680 moieties linked to the PAMAM dendrimer and docked to the A(2A) receptor was found to be similar to the binding mode of a monomeric CGS21680 ligand.

Development of a quantitative approach in blood plasma for low-dosed hallucinogens and opioids using LC-high resolution mass spectrometry.

The WHO annually reports an increasing abuse of new psychoactive substances (NPS), which are a heterogeneous group of synthetic drugs and are consumed as substitute for controlled drugs of abuse. In this work, we focused on highly potent derivatives such those of phenethylamine (2C), N-2-methoxybenzyl phenethylamine (NBOMes), lysergic acid diethylamide (LSD), and fentanyl. Severe to fatal intoxications were described due to their high potency. Therefore, they have to be taken at very low doses resulting in low blood concentration in the low ng/mL range, which is a challenge for reliable analytical detection and quantification. The aim of this work was therefore to design a simple, robust, and fast method for simultaneous detection and quantification of multiple substances of the different classes in human blood plasma using liquid chromatography (LC) high resolution (HR) mass spectrometry (MS) with alternating HR full-scan (HRFS) MS and "All-ions fragmentation" (AIF) MS. The paper contains results of the method validation according to the EMA guideline, including intra-/interday accuracy and precision, matrix effects, storage and benchtop analyte stability as well as selectivity and carryover. All validation criteria were fulfilled for most tested compounds except for the NBOMe derivatives, one out of ten 2C-derivatives and butyryl fentanyl, which failed at accuracy and/or precision or at the acceptance criteria for matrix effect. Reasons for this are discussed and solutions presented. Despite some limitations, the HRFS + AIFMS analysis allowed detection of most of the analytes down to 0.1ng/mL, seamless integration of new or unexpected analytes, identification and quantification with no limitations on the number of monitored compounds, and reevaluation of the acquired data also concerning metabolism studies using group-indicating fragment ions.

Noninvasive assessment of dofetilide plasma concentration using a deep learning (neural network) analysis of the surface electrocardiogram: A proof of concept study.

BACKGROUND: Dofetilide is an effective antiarrhythmic medication for rhythm control in atrial fibrillation, but carries a significant risk of pro-arrhythmia and requires meticulous dosing and monitoring. The cornerstone of this monitoring, measurement of the QT/QTc interval, is an imperfect surrogate for plasma concentration, efficacy, and risk of pro-arrhythmic potential. OBJECTIVE: The aim of our study was to test the application of a deep learning approach (using a convolutional neural network) to assess morphological changes on the surface ECG (beyond the QT interval) in relation to dofetilide plasma concentrations. METHODS: We obtained publically available serial ECGs and plasma drug concentrations from 42 healthy subjects who received dofetilide or placebo in a placebo-controlled cross-over randomized controlled clinical trial. Three replicate 10-s ECGs were extracted at predefined time-points with simultaneous measurement of dofetilide plasma concentration We developed a deep learning algorithm to predict dofetilide plasma concentration in 30 subjects and then tested the model in the remaining 12 subjects. We compared the deep leaning approach to a linear model based only on QTc. RESULTS: Fourty two healthy subjects (21 females, 21 males) were studied with a mean age of 26.9 ± 5.5 years. A linear model of the QTc correlated reasonably well with dofetilide drug levels (r = 0.64). The best correlation to dofetilide level was achieved with the deep learning model (r = 0.85). CONCLUSION: This proof of concept study suggests that artificial intelligence (deep learning/neural network) applied to the surface ECG is superior to analysis of the QT interval alone in predicting plasma dofetilide concentration.