Rapid nanomolar detection of cocaine in biofluids by electrochemical aptamer-based sensor with low-temperature effect for drugged driving screening.

Cocaine is one of the most abused illicit drugs, and its abuse damages the central nervous system and can even lead directly to death. Therefore, the development of simple, rapid and highly sensitive detection methods is crucial for the prevention and control of drug abuse, traffic accidents and crime. In this work, an electrochemical aptamer-based (EAB) sensor based on the low-temperature enhancement effect was developed for the direct determination of cocaine in bio-samples. The signal gain of the sensor at 10 °C was greatly improved compared to room temperature, owing to the improved affinity between the aptamer and the target. Additionally, the electroactive area of the gold electrode used to fabricate the EAB sensor was increased 20 times by a simple electrochemical roughening method. The porous electrode possesses more efficient electron transfer and better antifouling properties after roughening. These improvements enabled the sensor to achieve rapid detection of cocaine in complex bio-samples. The low detection limits (LOD) of cocaine in undiluted urine, 50% serum and 50% saliva were 70 nM, 30 nM and 10 nM, respectively, which are below the concentration threshold in drugged driving screening. The aptasensor was simple to construct and reusable, which offers potential for drugged driving screening in the real world.

Comparing the acute toxicities of co-exposure to cocaine and ethanol versus cocaine alone.

INTRODUCTION: Cocaine is commonly consumed with ethanol, which leads to the formation of cocaethylene through transesterification. Cocaethylene is an active metabolite of cocaine with a longer duration of action. Literature on the combined toxicity of cocaine, ethanol, and cocaethylene is conflicting. We aimed to compare the acute toxicities of co-exposure to cocaine and ethanol versus cocaine alone in Hong Kong. METHODS: This was a retrospective study on acute cocaine toxicities reported to the Hong Kong Poison Control Center from 1 January 2010 to 22 January 2023. Cocaine exposure was confirmed by urine immunoassays/laboratory tests and ethanol co-ingestion was confirmed by blood ethanol concentrations. A serious outcome was defined as a National Poison Data System outcome moderate or above. Univariate analyses and multivariable logistic regression were performed to compare the associations of clinical outcomes with and without ethanol, followed by subgroup analyses of cases with complete data. RESULTS: We analyzed 109 patients (median age 29 years, 71% men, 68% Chinese), of whom 20 had confirmed ethanol co-ingestion (mean blood ethanol concentration 1350 mg/L). Multivariable analysis showed that co-exposure to cocaine and ethanol was associated with a lower risk of serious outcomes (adjusted odds ratio 0.09, 95% confidence interval 0.01-0.77; p = 0.03) after adjusting for age, sex, ethnicity, route of cocaine administration, and physical health status. Subgroup analyses showed similar findings. CONCLUSIONS: In contrast to previous studies, we did not identify a higher risk of serious outcomes after co-exposure to cocaine and ethanol compared to cocaine alone in a predominantly Chinese cohort.

Label-free SERS-ML detection of cocaine trace in human blood plasma.

The widespread consumption of cocaine poses a significant threat to modern society. The most effective way to combat this problem is to control the distribution of cocaine, based on its accurate and sensitive detection. Here, we proposed the detection of cocaine in human blood plasma using a combination of surface enhanced Raman spectroscopy and machine learning (SERS-ML). To demonstrate the efficacy of our proposed approach, cocaine was added into blood plasma at various concentrations and drop-deposited onto a specially prepared disposable SERS substrate. SERS substrates were created by deposition of metal nanoclusters on electrospun polymer nanofibers. Subsequently, SERS spectra were measured and as could be expected, the manual distinguishing of cocaine from the spectra proved unfeasible, as its signal was masked by the background signal from blood plasma molecules. To overcome this issue, a database of SERS spectra of cocaine in blood plasma was collected and used for ML training and validation. After training, the reliability of proposed approach was tested on independently prepared samples, with unknown for SERS-ML cocaine presence or absence. As a result, the possibility of rapid determination of cocaine in blood plasma with a probability above 99.5% for cocaine concentrations up to 10-14 M was confirmed. Therefore, it is evident that the proposed approach has the ability to detect trace amounts of cocaine in bioliquids in an express and simple manner.

Development of an innovative analytical method for forensic detection of cocaine, antidepressants, and metabolites in postmortem blood using magnetic nanoparticles.

Cocaine and antidepressants rank high globally in substance consumption, emphasizing their impact on public health. The determination of these compounds and related substances in biological samples is crucial for forensic toxicology. This study focused on developing an innovative analytical method for the determination of cocaine, antidepressants, and their related metabolites in postmortem blood samples, using unmodified commercial Fe3O4 nanoparticles as a sorbent for dispersive magnetic solid-phase extraction (m-d-SPE), coupled with liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis. An aliquot of 100 µL of whole blood and 5 µL of the internal standard pool were added to 30 mg of nanoparticles. The nanoparticles were separated from the sample using a neodymium magnet inserted into a 3D-printed microtube rack. The liquid was then discarded, followed by desorption with 300 µL of 1/1/1 acetonitrile/methanol/ethyl acetate. The sample was vortexed and separated, and 1.5 µL of the organic supernatant was injected into the LC-MS/MS. The method was acceptably validated and successfully applied to 263 postmortem blood samples. All samples evaluated in this study were positive for at least one substance. The most frequent analyte was benzoylecgonine, followed by cocaine and cocaethylene. The most common antidepressants encountered in the analyzed samples were citalopram and fluoxetine, followed by fluoxetine's metabolite norfluoxetine. This study describes the first report of this sorbent in postmortem blood analysis, demonstrating satisfactory results for linearity, precision, accuracy, and selectivity for all compounds. The method's applicability was confirmed, establishing it as an efficient and sustainable alternative to traditional techniques for forensic casework.

Driving under the influence of cocaine and MDMA: Relationship between blood concentrations and results from clinical test of impairment.

The general use of cocaine is increasing in recent years, while the trend for 3,4-methylenedioxymethamphetamine (MDMA) is less clear. The relationship between blood concentrations and impairment is poorly understood, which complicates interpretation. The aims of this study were to report prevalence and blood concentrations of cocaine and MDMA in drugged drivers, and to investigate the relationship between blood concentrations and impairment. Samples of whole blood were collected from apprehended drivers in the period 2000-2022, and a clinical test of impairment (CTI) was simultaneously performed. The samples were initially analyzed for cocaine and MDMA using gas chromatography-mass spectrometry (until 2009 and 2012, respectively), and later using ultra-high-performance liquid chromatography-tandem mass spectrometry. Overall, cocaine was detected in 2,331 cases and MDMA in 2,569 cases. There were 377 and 85 mono cases of cocaine and MDMA, respectively. In the mono cases, the median cocaine concentration was 0.09 mg/L (range: 0.02-1.15 mg/L), and 54% of the drivers were clinically impaired. The median MDMA concentration was 0.19 mg/L (range: 0.04-1.36 mg/L), and 38% were clinically impaired. There was a statistically significant difference in the median cocaine concentration between drivers assessed as not impaired (0.07 mg/L) and drivers assessed as impaired (0.10 mg/L) (P = 0.009). There was also a significant effect of the blood concentration of cocaine (adjusted odds ratio [aOR] = 6.42, 95% confidence interval [CI] = 1.13-36.53, P = 0.036) and driving during the evening/night-time (aOR = 2.17, 95% CI = 1.34-3.51, P = 0.002) on the probability of being assessed as impaired on the CTI. No significant differences were found for MDMA. Many drivers are not assessed as impaired on a CTI following cocaine or especially MDMA use. For cocaine, a relationship between blood concentrations and impairment was demonstrated, but this could not be shown for MDMA.

A two-year review of cocaine findings in impaired driving investigations in Ontario, Canada.

Drug-impaired driving is an increasing public safety concern across Canada, particularly due to the demonstrated increase in use of recreational drugs such as cocaine. Cocaine is a central nervous system stimulant drug; however, it can impair an individual's driving ability in both the stimulant and crash phases. Despite the scientific consensus regarding cocaine's potential for driving impairment, there is relatively little information available regarding blood concentrations and associated observations of impairment in suspected impaired drivers. Retrospective data analysis was performed to evaluate suspected impaired driving cases in which cocaine and/or benzoylecgonine were detected alone, or in combination with other drugs, in blood and urine samples submitted to the Toxicology Section of the Centre of Forensic Sciences with incident dates between 2021 and 2022. Cocaine and/or benzoylecgonine were detected in 46% (blood) and 66% (urine) of the total impaired driving samples submitted. In 41 cases where cocaine and/or benzoylecgonine were the only drug finding in blood, concentrations of cocaine and benzoylecgonine ranged from 0.0073 to 0.26 mg/L (mean 0.096 mg/L) and 0.13 to 5.3 mg/L (mean 2.1 mg/L), respectively. Driving observations reported by the arresting officer in cases where cocaine and/or benzoylecgonine were the only drug finding in blood and urine included the driver being involved in a collision, the vehicle leaving the roadway, erratic driving and the driver being asleep at the wheel; observations of drug impairment reported by the drug recognition expert at the time of driver evaluation included abnormal speech patterns, poor balance/incoordination, abnormal body movements and the individual falling asleep. The results provide concentrations of cocaine and benzoylecgonine observed in suspected impaired drivers, insight into observations that may be associated with prior cocaine use and additional information to inform on the effects of cocaine on driving.

Relationship between cocaine and cocaethylene blood concentration with the severity of clinical manifestations.

BACKGROUND: Poisonings resulting from the abuse of drugs currently represent a serious problem for public health. Among the main agents involved, cocaine stands out. It became one of the most abused drugs around the world, and one of the main reasons for visits to the emergency department due to the use of illicit substances. The use of cocaine is primarily in combination with alcoholic beverages. There are few studies that correlate cocaine blood concentration and the severity of clinical manifestations in patients evaluated at Emergency Department. The aim of the present study was to verify the possible relationship between the blood concentration of cocaine and cocaethylene (product of the interaction of cocaine with ethanol) with the severity of the clinical manifestations presented by patients with cocaine intoxication. METHODS: Blood levels were measured by high-performance liquid chromatography (HPLC) and the severity of clinical manifestations was assessed using the Stimulant Intoxication Score (SIS). To establish this relationship, Pearson's chi-square statistical test (x2) was used for categorical variables and Student's t for continuous variables, with statistical significance of 5% (p < 0.05). RESULTS: Of the 81 patients included in the study, 77.8% were men with a mean age of 32.5 years ± 8.5 and mean of SIS 3.4 ± 2.5. Considering the toxicological analysis results, 24.7% of the blood samples were positive. The mean of cocaine and cocaethylene concentrations were 0.34 µg/mL ± 0.45 and 0.38 µg/mL ± 0.34, respectively. The blood concentration of cocaine and cocaethylene has not been shown to be useful information for the treatment and prognosis of patients, but blood levels of these substances at the time of treatment, regardless of their concentration, may be an indicator of severity, showing that any concentrations of these substances should be considered as potentially toxic. CONCLUSION: The application of the SIS score proved to be an important alternative capable of predicting the severity of the patients due to cocaine intoxication in a fast and simplified way.

Planned complex suicide involving combined drug intoxication and femoral catheterization.

Complex planned suicide is characterized by the simultaneous use of two or more methods to ensure that death occurs even if one method fails. The authors present an original combination of two self-killing methods. A 42-year-old cardiologist, with a major depressive syndrome and several suicide attempts, as well as cocaine addiction, was found dead at his home with a femoral catheter inserted in the right femoral artery. The autopsy concluded that death was due to major hemorrhagic process in a context of suicide. Toxicological analyses, performed in peripheral blood by gas chromatography coupled to mass spectrometry and by liquid chromatography-diode array detection, revealed the presence of ethanol (0.13 g/L), cocaine, and metabolites (cocaine: 432 µg/L, benzoylecgonine: 3286 µg/L, ecgonine methyl ester: 1195 µg/L, cocaethylene: 41 µg/L), a potentially lethal concentration of citalopram (1.03 mg/L), toxic concentrations of hydroxyzine (0.11 mg/L), bromazepam (2.06 mg/L), and lidocaine (7.30 mg/L). At the end of these analyses, the death was reclassified as planned complex suicide combining drug intoxication and catheterization of the femoral artery. The authors discuss the main aspects of this case and stress the importance of meticulous analysis of all available evidence: witness reports, victim's medical history and occupation, findings of at-the-scene examination, autopsy, and toxicological analyses, in order to exclude homicide and to understand the sequence of events that led to death.

Pharmacokinetic and pharmacodynamic analyses of cocaine and its metabolites in behaviorally divergent inbred mouse strains.

Cocaine (COC) is a psychostimulant with a high potential for abuse and addiction. Risk for COC use disorder is driven, in part, by genetic factors. Animal models of addiction-relevant behaviors have proven useful for studying both genetic and nongenetic contributions to drug response. In a previous study, we examined initial locomotor sensitivity to COC in genetically diverse inbred mouse strains. That work highlighted the relevance of pharmacokinetics (PK) in initial locomotor response to COC but was limited by a single dose and two sampling points. The objective of the present study was to characterize the PK and pharmacodynamics of COC and its metabolites (norcocaine and benzoylecgonine) in six inbred mouse strains (I/LnJ, C57BL/6J, FVB/NJ, BTBR T+ tf/J, LG/J and LP/J) that exhibit extreme locomotor responses to cocaine. Mice were administered COC at one of four doses and concentrations of cocaine, norcocaine and benzoylecgonine were analyzed in both plasma and brain tissue at 5 different time points. Initial locomotor sensitivity to COC was used as a pharmacodynamic endpoint. We developed an empirical population PK model that simultaneously characterizes cocaine, norcocaine and benzoylecgonine in plasma and brain tissues. We observed interstrain variability occurring in the brain compartment that may contribute to pharmacodynamic differences among select strains. Our current work paves the way for future studies to explore strain-specific pharmacokinetic differences and identify factors other than PK that are responsible for the diverse behavioral response to COC across these inbred mouse strains.

Optimization of cloned enzyme donor immunoassay cut-offs for drugs of abuse in post-mortem whole blood.

INTRODUCTION: Immunoassay (IA) tests are not widely applied in post-mortem samples, since they are based on technologies requiring relatively non-viscous specimens, and compounds originating from the degradation of proteins and lipids during the post-mortem interval can alter the efficiency of the test. However, since the extraction techniques for IA tests are normally rapid and low-cost, IA could be used as near-body drug-screening for the classes of drugs most commonly found in Italy and Europe. In this study, semi-quantitative results on post-mortem whole blood samples obtained through CEDIA analysis (cannabinoids, cocaine, amphetamine compounds, opiates and methadone), were compared with results of confirmatory analysis obtained using GC-MS. Screening cut-offs for all drugs were retrospectively optimized. METHODS: Post-mortem whole blood samples from autopsy cases of suspected fatal intoxication were collected over 3 years. Samples were initially analyzed through CEDIA (CEDIA, ILab 650, Werfen). Confirmatory analyses were then performed by GC-MS (QP 2010 Plus, Shimadzu). Screening cut-offs were retrospectively optimized using Receiver Operating Characteristic (ROC) analysis. RESULTS: CEDIA results were available for 125 samples. Two-hundred-eighty-nine (289) positive screening results were found. Among these, 162 positive confirmation results were obtained. Optimized screening cut-offs were as follows: 6.5ng/ml for THC; 4.2ng/ml for THC-COOH; 12.0ng/ml for cocaine; 6.6ng/ml for benzoylecgonine; 6.4ng/ml for opiates; 2.0ng/ml for methadone. Analysis of ROC-curves showed a satisfying degree of separation in all tests except for amphetamine compounds, with areas under the curve (AUC) between 0.915 (THC) and 0.999 (for benzoylecgonine and methadone). DISCUSSION: The results of the study showed that CEDIA screening at the optimized cut-offs exhibits a very high sensitivity and good specificity and positive predictive value (PPV) for cannabinoids, cocaine and metabolites, opiates and methadone. A high number of false positives (n=19) for amphetamine compounds was observed at the optimized cut-off, resulting in a very low PPV, which is also influenced by the very low number of TP (n=4). CONCLUSION: The results of the study show that the CEDIA is a valuable screening test on post-mortem whole blood for cannabinoids, cocaine and metabolites, opiates and methadone, but it is not recommended for amphetamine compounds, due to the high number of false positives. The strengths of the study are the large sample size, the inclusion of post-mortem cases only and the high level of sensitivity and specificity obtained at the optimized cut-offs.

Do dried blood spots (DBS) have the potential to support result management processes in routine sports drug testing?

Dried blood spots (DBS) have been considered as complementary matrix in sports drug testing for many years. Especially concerning substances prohibited in-competition only, the added value of DBS collected concomitantly with routine doping control urine samples has been debated, and an increasing potential of DBS has been discussed in the scientific literature. To which extent and under which prerequisites DBS can contribute to enhanced anti-doping efforts is currently evaluated. As a proof-of-principle, two analytical applications, one targeting cocaine/benzoyl ecgonine and the other prednisone/prednisolone, are presented in this perspective to indicate potential added value but also presently existing limitations of the DBS approach.

Blood and Plasma Volumetric Absorptive Microsampling (VAMS) Coupled to LC-MS/MS for the Forensic Assessment of Cocaine Consumption.

Reliable, feasible analytical methods are needed for forensic and anti-doping testing of cocaine and its most important metabolites, benzoylecgonine, ecgonine methyl ester, and cocaethylene (the active metabolite formed in the presence of ethanol). An innovative workflow is presented here, using minute amounts of dried blood or plasma obtained by volumetric absorptive microsampling (VAMS), followed by miniaturized pretreatment by dispersive pipette extraction (DPX) and LC-MS/MS analysis. After sampling 20 µL of blood or plasma with a VAMS device, the sample was dried, extracted, and loaded onto a DPX tip. The DPX pretreatment lasted less than one minute and after elution with methanol the sample was directly injected into the LC-MS/MS system. The chromatographic analysis was carried out on a C8 column, using a mobile phase containing aqueous formic acid and acetonitrile. Good extraction yield (> 85%), precision (relative standard deviation, RSD < 6.0%) and matrix effect (< 12%) values were obtained. Analyte stability was outstanding (recovery > 85% after 2 months at room temperature). The method was successfully applied to real blood and plasma VAMS, with results in very good agreement with those of fluid samples. The method seems suitable for the monitoring of concomitant cocaine and ethanol use by means of plasma or blood VAMS testing.

A machine learning approach for handling big data produced by high resolution mass spectrometry after data independent acquisition of small molecules - Proof of concept study using an artificial neural network for sample classification.

Liquid chromatography coupled to high-resolution mass spectrometry (HRMS) enables data independent acquisition (DIA) and untargeted screening. However, to avoid the handling of the resulting large dataset, most laboratories in that field still use targeted screening methods, which offer good sensitivity and specificity but are limited to known compounds. The promising field of machine learning offers new possibilities such as artificial neural networks that can be trained to classify large amounts of data. In this proof of concept study, we exemplify such a machine learning approach for raw HRMS-DIA data files. We evaluated a machine learning model using training, validation, and test sets of solvent and whole blood samples containing drugs (of abuse) common in forensic toxicology. For that purpose, different platforms were used. With a feedforward neural network model architecture, a category prediction (blank sample vs. drug containing sample) was aimed for. With the applied machine learning approaches, the sensitivity and specificity, of the validation and test set, for the prediction of sample classes were in a suitable range for an actual use in a (routine) laboratory (e.g. workplace drug testing). In conclusion, this proof of concept study clearly demonstrated the huge potential of machine learning in the analysis of HRMS-DIA data.

Selective extraction of cocaine from biological samples with a miniaturized monolithic molecularly imprinted polymer and on-line analysis in nano-liquid chromatography.

We report the on-line coupling of a monolithic molecularly imprinted polymer to nano-liquid chromatography for the selective analysis of cocaine and its main metabolite, benzoylecgonine, in complex biological samples. After the screening of different synthesis conditions, a monolithic molecularly imprinted polymer was in situ synthesized into a 100 µm internal diameter fused-silica capillary using cocaine as template, methacrylic acid as functional monomer, and trimethylolpropane trimethacrylate as cross-linker. Scanning electron microscopy was used to assess the homogeneous morphology of the molecularly imprinted polymer and its permeability was measured. Its selectivity was evaluated by nano-liquid chromatography-ultraviolet, leading to imprinting factors of 3.2 ±â€¯0.5 and 2.2 ±â€¯0.3 for cocaine and benzoylecgonine, respectively, on polymers resulting from three independent syntheses, showing the high selectivity and the repeatability of the synthesis. After optimizing the extraction protocol to promote selectivity, the monolithic molecularly imprinted polymer was successfully on-line coupled with nano-liquid chromatography-ultraviolet for the direct extraction and analysis of cocaine present in spiked human plasma and saliva samples. The repeatability of the obtained extraction recovery, between 85.4 and 98.7% for a plasma sample spiked at 100 ng mL-1, was high with relative standard deviation values lower than 5.8% for triplicate analyses on each of the three independently synthesized molecularly imprinted polymers. A linear calibration range was achieved between 100 and 2000 ng mL-1 (R2 = 0.999). Limits of quantification of 14.5 ng mL-1 and 6.1 ng mL-1 were achieved in plasma and urine samples, respectively. The very clean-baseline of the resulting chromatogram illustrated the high selectivity brought by the monolithic molecularly imprinted polymer that allows the removal of a huge peak corresponding to the elution of interfering compounds and the easy determination of the target analyte in these complex biological samples.

Simultaneous Determination of Cocaine and Metabolites in Human Plasma Using Solid Phase Micro-Extraction Fiber Tips C18 and UPLC-MS/MS.

The determination of cocaine (COC) and its metabolites ecgonine methyl ester (EME), benzoylecgonine (BZE), norcocaine (NCOC) and cocaethylene (CE) in human plasma is relevant in clinical and forensic toxicology. An efficient extraction and clean-up of plasma specimens for the simultaneous determination of BZE along with COC and basic metabolites is challenging due to their widely different polarities and ionization characteristics. Recently, biocompatible SPME LC tips C18 became commercially available. We applied SPME LC tips C18 to the simultaneous extraction of COC, BZE, EME, NCOC, and CE by direct immersion of the fiber in plasma diluted with a buffer at pH 8.0. Analytes were desorbed from the fiber to methanol containing formic acid and injected into a UPLC-MS/MS system. The assay was linear from 5 to 500 ng mL-1. Precision assays presented CV% in the range of 2.22 to 10.54%, and accuracy was in the range of 93.4-108.1%. The assay requires minimal quantities of plasma and organic solvents, allowing multiple extractions in parallel. Biocompatible SPME is a promising alternative for preparing biological samples prior to drug measurement by UPLC-MS/MS.

Microsampling with cotton thread: Storage and ultra-sensitive analysis by thread spray mass Spectrometry.

Storage and quantitative analysis of small volumes of biofluids are challenging, especially when low concentrations of analytes are to be detected in the presence of complex matrices. In this study, we describe an integrated thread-based approach for stabilizing small blood volumes in the dry-state at room temperature, while also offering direct analysis capabilities via thread spray mass spectrometry. The analytical merits of this novel microsampling platform was demonstrated via the direct analysis of diazepam and cocaine in dried blood samples stored for 42 days. In-situ in-capillary blood processing from hydrophobic threads enabled limits of detection as low as parts-per-quadrillion to be reached. We validated this ultra-sensitivity by analyzing small tissue-like residues collected after pushing a thread through the sample once. The implications of this sample collection, storage, and analysis platform can be extensive with direct applications in forensics and clinical studies.

Prevention of Alcohol and Other Drug Overuse Among Nightclub Patrons: A Randomized Trial of a Group-Based Mobile Intervention at Nightclubs.

OBJECTIVE: Electronic music dance events (EMDEs) at nightclubs attract young adults engaging in high-risk alcohol and other drug (AOD) use. Studies show that most patrons arrive at clubs in groups and that these peer groups influence drinking. Therefore, peer groups are a natural context for preventing risk behaviors. This article examined outcomes of a randomized controlled trial of a group-based mobile intervention at nightclubs, Nightlife Safety Plans (NSP). METHOD: The sample comprised 352 groups, consisting of 959 participants (45.3% female) at 41 events across seven nightclubs hosting EMDEs. Club patrons were surveyed anonymously and completed breath tests as they entered and exited clubs. Oral fluid samples collected from patrons at exit assessed drug use. Analyses examining assignment to NSP versus a control condition on fire safety predicted individual- and group-level protective strategy use and AOD use, controlling for background variables. RESULTS: At the individual level, participation in NSP was related to increased protective actions to keep group members safe. No effects were found on actions to keep oneself safe or in response to overuse. At the group level, assignment to NSP was related to a higher average number of group safety strategies. Participation in NSP was associated with lower blood alcohol concentration but unrelated to tetrahydrocannabinol and cocaine. CONCLUSIONS: NSP appears to be efficacious for increased protective actions to keep group members safe from overuse and for reduced blood alcohol concentration among EMDE patrons. The findings support the use of an intervention utilizing group-based strategies presented proximal to risk settings.

Detection of cocaine and its metabolites in whole blood and plasma following a single dose, controlled administration of intranasal cocaine.

The disposition of drugs and their metabolites have been extensively described in the literature, based primarily on the analysis of plasma and urine. However, there are more limited data on their disposition in whole blood, which is often the only specimen available in forensic investigations and cases of driving under the influence of drugs. In this study, we have, for the first time, established pharmacokinetic properties of cocaine (COC) and its metabolites from concurrently collected whole blood and plasma samples, following a single 100 mg dose of cocaine hydrochloride administered via nasal insufflation to seven healthy volunteers. The median Cmax of COC and its major metabolites, benzoylecgonine (BZE) and ecgonine methyl ester (EME), were closely related in whole blood and plasma. The median Cmax for COC in plasma was 379.7 ng/mL (347.5-517.7) and 344.24 ng/mL (271.6-583.2) in whole blood. The median Cmax for BZE in plasma was 441.2 ng/mL (393.6-475. and 371.18 ng/mL (371.1-477.3) in whole blood, EME was 105.5 ng/mL (93.6-151.8) in plasma and 135.5 ng/mL (87.8-183) in whole blood. Calculated medians of the whole blood to plasma ratio of COC (0.76), BZE (0.98) and EME (1.02) of approximately 1, strongly suggesting that the erythrocyte cell wall presents no barrier to COC and its metabolites. Furthermore, whole blood and plasma concentrations of COC were strongly correlated (R2  = 0.0914 R = 0.956, p < 0.0001), as was BZE (R2  = 0.0932 R = 0.965, p < 0.0001) and EME (R2  = 0.0964R = 0.928, p < 0.0001). The minor oxidative metabolite norcocaine (NCOC) was detected in both whole blood and plasma at concentrations between 1 and 5 ng/mL within 60-180 minutes, suggesting that NCOC could be indicator of recent COC administration. Data from this study have shown for the first time that COC and its metabolites BZE and EME are evenly distributed between plasma and whole blood following controlled single-dose intranasal COC administration.

Simultaneous determination of cocaine, ecgonine methyl ester, benzoylecgonine, cocaethylene and norcocaine in dried blood spots by ultra-performance liquid chromatography coupled to tandem mass spectrometry.

Cocaine (COC) is one of the most widely abused drugs in the world and its sensitive and its reliable measurement in blood is of great importance in the field of forensic and clinical toxicology. Additionally, the determination of COC metabolites such as benzoylecgonine (BZE), cocaethylene (CE), ecgonine methyl ester (EME), and norcocaine (NCOC) are also of complementary diagnostic value. The quantification of COC and metabolites in dried blood spots (DBS) may be an alternative to conventional collection methods with several advantages, including easier, on-site, collection, transportation and storage. In this study, we present a simple and comprehensively validated UPLC-MS/MS assay to measured COC, BZE, EME, NCOC and CE in DBS. The evaluated assay was linear from 5-500 ng mL-1. Precision assays presented CV% of 1.27-6.82, and accuracy in the range of 97-113.78%. Low haematocrit values had a negative impact in the assay accuracy. COC, BE, NCOC and CE measurements can be made reliably in DBS stored for 14 days at room temperature, as well as at -20 °C and 45 °C. All evaluated compounds can be measured in DBS maintained at -20 °C for 14 days. DBS sampling can be used for the clinical evaluation of the exposure to COC, being an alternative for collection, short-term storage and transportation of blood at room and high temperatures.

False-Positive Serum Cocaine Screening Results in Patients Undergoing Evaluation for Renal Transplant.

Drug screening during pre-transplant evaluations can have major implications for patient care, particularly because drug abuse has been associated with poor transplant outcomes. Although urine drug screening is usually preferred, serum testing is available for situations such as anuria due to end stage renal disease. However, there are few studies evaluating serum drug screening in specific populations such as patients undergoing kidney transplant evaluation. All serum drug screens ordered between January 2015 and November 2017 on patients being evaluated for renal transplant were compared against a large population of serum drug screens ordered from other institutions. Cocaine screening and confirmation results were evaluated to determine false positives. Cocaine screens were positive in 23 of 537 (4.3%) pre-transplant samples, and 211 of 5,115 (4.1%) comparison samples. Confirmation testing demonstrated that 14 (60.9%) pre-transplant samples were false positives, which was significantly (P < 0.01) higher than the rate of false positives in the comparison group (47/211, 22.3%). No common medication or other cross-reacting substance could be identified in the pre-transplant cohort to explain the false-positive results. Although serum cocaine screening had a low overall false-positive rate, the proportion of false positives was significantly higher in pre-transplant patients. Given the poor transplant outcomes associated with drug abuse, failure to properly interpret screening results as being false positives could negatively affect patient care. All members of the transplant team should recognize the importance of confirmation testing in this setting, to avoid unintended consequences due to false-positive screening results.