Development of Carbon Paste Electrode Chemically Modified with Schiff Base Complexes for Forensic Analysis of Cocaine

In this article we have studied the electrochemical behavior of cocaine hydrochloride on the surface of a carbon paste electrode chemically modified with a Schiff base complex, namely [FeIII(salen)], [ZrOII(salen)], or [NiII(salen)], during voltametric analyses. Among the tested complexes, [NiII(salen)] provided amperometric and thermal stability and it was only degraded at temperatures above 400 ºC. To prepare the cocaine hydrochloride was used hydrochloric acid (HCl 1 mol L-1) after we tested the electrode, the HCl did not cause electrode passivation. In this study we can see that the voltammetric analyses revealed a satisfactory result, that the peak current obtained between 0.1 and 0.2 V (vs. Ag/AgCl) varied linearly with cocaine hydrochloride concentration and the average amperometric sensitivity, the LOD, and the LOQ were 5.5 μmol L-1, 0.945 μmol L-1, and 3.16 μmol L-1, respectively.

Use of Paper Microdevices in the Identification and Quantification of Cocaine in Seized Street Samples

The growing consumption of illicit drugs in Brazil is becoming increasingly problematic for society. It is therefore critical to develop technologies to combat drug trafficking that allow for rapid, non-invasive evaluation of drug samples. Microfluidics is a technology that manipulates and studies small amounts of fluids, using structures with dimensions from ten to hundreds of micrometers (microdevices). The main advantages of microfluidic approaches are its low cost, speed, and ability to provide results in loco. Here, paper microfluidics were developed to perform the modified Scott test to calculate the cocaine hydrochloride content in seized samples of cocaine (n = 30) and crack (n = 30). A smartphone with the Photometrix® app was used to construct a model for quantifying the samples. A factorial model was developed to optimize microfluidic analytical parameters such as spot size (6, 8 and 10 mm), reagent content (50, 75, and 100% cobalt thiocyanate II), cocaine hydrochloride concentration (4, 6 and 8 mg mL-1) and response time (or analyte detection; t = 0, 0.5 1, 12 and 24 h). After experimental planning, a diameter of ΜPADs = 8 mm - [Co(SCN)2] = 100% and a 1 h response time were identified as the best conditions. We observed that the cocaine hydrochloride concentration did not influence the model. A sample concentration of 15 mg mL-1 was used to quantify cocaine hydrochloride in street samples apprehended by the Forensic Police of Espírito Santo state (with n = 60). The quantification curve constructed to determine the cocaine hydrochloride concentration showed a determination coefficient, R2, of 0.98246 and RMSEC (root mean squares error calibration - mean square error of the calibration) of 0.39480, with a LOD and LOQ of 0.09 and 0.30 mg mL-1, respectively. For the crack samples, the cocaine hydrochloride concentrations ranged from 2.5 to 60.8 wt% with an average purity content of 21.3 ± 13.3 wt%. For the seized cocaine samples, variation in hydrochloride content from 1.2 to 22.6 wt% was observed with a mean percentage of 14.19 ± 6.92 wt%. Finally, chemometric tools such as principal component analysis were used to assess the similarity among the samples.

Cocaine-Induced Changes in Tonic Dopamine Concentrations Measured Using Multiple-Cyclic Square Wave Voltammetry in vivo

For over 40 years, in vivo microdialysis techniques have been at the forefront in measuring the effects of illicit substances on brain tonic extracellular levels of dopamine that underlie many aspects of drug addiction. However, the size of microdialysis probes and sampling rate may limit this technique’s ability to provide an accurate assessment of drug effects in microneural environments. A novel electrochemical method known as multiple-cyclic square wave voltammetry (M-CSWV), was recently developed to measure second-to-second changes in tonic dopamine levels at microelectrodes, providing spatiotemporal resolution superior to microdialysis. Here, we utilized M-CSWV and fast-scan cyclic voltammetry (FSCV) to measure changes in tonic or phasic dopamine release in the nucleus accumbens core (NAcc) after acute cocaine administration. Carbon-fiber microelectrodes (CFM) and stimulating electrodes were implanted into the NAcc and medial forebrain bundle (MFB) of urethane anesthetized (1.5 g/kg i.p.) Sprague-Dawley rats, respectively. Using FSCV, depths of each electrode were optimized by determining maximal MFB electrical stimulation-evoked phasic dopamine release. Changes in phasic responses were measured after a single dose of intravenous saline or cocaine hydrochloride (3 mg/kg; n = 4). In a separate group, changes in tonic dopamine levels were measured using M-CSWV after intravenous saline and after cocaine hydrochloride (3 mg/kg; n = 5). Both the phasic and tonic dopamine responses in the NAcc were augmented by the injection of cocaine compared to saline control. The phasic and tonic levels changed by approximately x2.4 and x1.9, respectively. These increases were largely consistent with previous studies using FSCV and microdialysis. However, the minimal disruption/disturbance of neuronal tissue by the CFM may explain why the baseline tonic dopamine values (134 ± 32 nM) measured by M-CSWV were found to be 10-fold higher when compared to conventional microdialysis. In this study, we demonstrated phasic dopamine dynamics in the NAcc with acute cocaine administration. M-CSWV was able to record rapid changes in tonic levels of dopamine, which cannot be achieved with other current voltammetric techniques. Taken together, M-CSWV has the potential to provide an unprecedented level of physiologic insight into dopamine signaling, both in vitro and in vivo, which will significantly enhance our understanding of neurochemical mechanisms underlying psychiatric conditions.

Study of cocaine seizures through spatial analysis

Cocaine trafficking and consumption continues to prosper despite the public policies that are in force in Brazil, despite its use for thousands of years, it is currently a public health problem. This study aimed to report the sociodemographic variables of individuals apprehended with cocaine and who were framed in Law n°. 11,343 of August 2006, in the municipality of Campina Grande, in 2017. It was a hybrid study, with a transversal, retrospective cut and ecological, with a quantitative approach. The neighborhood area variable was distributed in thematic maps and the spatial autocorrelation was measured by the Moran Global and Local indexes, which quantify the degree of autocorrelation. 210 cocaine seizures were recorded, of which 146 occurred in the municipality of Campina Grande, of these, only 94 presented all the data and were considered in this study. The months of September (n = 14) and October (n = 13) had the highest records of seizures. As for the pattern of use, crack in the yellowish stone form was predominant (n = 46), followed by cocaine hydrochloride in the form of white powder (n = 40). The profile of the individual apprehended with cocaine in the municipality was that of a young, single, unemployed and with low level of education. The predominant framework was drug trafficking (n = 75) according to Article nº. 33 of Law nº. 11,343 / 2006. The neighborhoods that registered the highest number of seizures were José Pinheiro (n = 15) and Pedregal (n = 8). The Moran General and Local indexis (p> 0.05), did not show spatial dependence between neighboring neighborhoods, that is, there is no autocorrelation for the analyzed variable.

Fatal N-Ethylhexedrone Intoxication

N-Ethylhexedrone [2-(ethyloamino)-1-phenylhexan-1-one; α-ethylaminohexanophenone (NEH)] is one of the most recent synthetic cathinones that appeared on the illegal market in late 2015. The majority of information concerning the model of consumption of NEH and its impact on the body originates only from self-reports from gray literature websites and drug forums. There are only limited data associated with the concentrations of NEH in blood samples available in the literature. This article presents a case of fatal NEH intoxication and a method for the determination of this substance in whole blood. A 21-year-old man without any diagnosed diseases was admitted to the hospital due to disorientation, aggression and finally loss of consciousness. Hyperthermia (>41°C), tachycardia (>160 beats per minute), tachypnea (20 breaths per minute), blood pressure (110/60 mmHg) and acute kidney failure were diagnosed. After a few hours of hospitalization, the patient died. A plastic bag with a white powder was found in his underwear. Analysis of the powder by another laboratory revealed cocaine hydrochloride; however, no cocaine or its metabolites were found in the biological material upon testing in our laboratory. Therefore, re-analysis of the powder was performed, and NEH was identified. Liquid–liquid extraction followed by liquid chromatography-triple quadrupole-mass spectrometry (LC-MS/MS) analysis were used for the determination of NEH in blood. The validation parameters were as follows: calibration range 1–250 ng/mL, accuracy 106.5–109.9%, precision 3.5–6.3%, recovery 90.1–96.9%, limit of detection 0.07 ng/mL and limit of quantification 1 ng/mL. NEH was quantified in the blood at a concentration of 145 ng/mL. Additionally, amphetamine at low concentrations and 11-nor-9-karboksy-Δ9-tetrahydrokannabinol (THC-COOH) were detected. Our study provided information on the possible lethal concentration and toxidrome that clinicians can observe for NEH-intoxicated patients and can be helpful during the preparation of toxicology analysis reports for a court of law for proper data interpretation.

Structural and functional signatures of executive deficits after early use of cocaine depend upon route of administration

BackgroundThere is growing evidence linking cocaine consumption with a broad spectrum of neurocognitive deficits. Despite of evidence suggesting that the route of administration should be taken into account to assess the short and long term effects of cocaine consumption, to our knowledge no study to date has characterized clinically relevant neuropsychological variables along with physiological variables separately in populations of individuals with histories of smoked cocaine dependence (SCD) and insufflated cocaine hydrochloride dependence (ICD).MethodsThe present study examined a sample of (a) 25 participants who fulfilled criteria for SCD, (b) 22 participants who fulfilled criteria for ICD, and (c) 25 healthy controls matched by age, gender, education, and socioeconomic status. An exhaustive neuropsychological battery was used to assess different cognitive domains (attention, executive functions, fluid intelligence, memory, language and social cognition). We complemented this neuropsychological assessment with the acquisition and analysis of structural (MRI) and functional (fMRI) neuroimaging data.ResultsDifferent routes of administration led to equally different profiles of neurocognitive impairment, with the SCD group being specifically associated with deficits in attention and executive functions. Consistent with risk models, executive function-attention deficit is better explained for age and age onset of consumption initiation. SCD also presented reduced grey matter density relative to ICD in the bilateral caudate, a key area for executive functions and attention. Connectivity between left caudate and inferior frontal regions mediates performance-structure association.ConclusionsCocaine routes of administration are associated to a differential profile that may not be due direct effects of stimulant action but also driven by cognitive and biological differences in key executive functioning and attention areas. This point the critical importance of the routes of administration. This information could inform clinical management and should be taken into account in clinical research.