What's in drugs freely used by Brazilian truck drivers - "Rebites"? Determination of target and nontarget compounds by high-resolution mass spectrometry and nuclear magnetic resonance.

Highways, the lifeline of the Brazilian economy, transport approximately 75% of the country's economic activity, highlighting its importance. However, professional drivers, accustomed to long daily journeys, make use of tablets widely available in Gas Station, which are known as "Rebites," which could contain a mixture of legal and illegal compounds. Thus, this study aims at the chemical characterization of these through different analytical methods. Initially, we performed a comprehensive screening of compounds present in seven samples collected across the country using high-resolution mass spectrometry (HRMS). The findings revealed caffeine as the main compound, alongside theophylline, lidocaine, and clobenzorex, among others. In the next step, we employ quantitative nuclear magnetic resonance (qNMR) to quantify the caffeine content in the tablets. The results indicated a caffeine concentration ranging between 14% and 31% (m/m), which may imply a daily overdose of this compound from around four tablets. In summary, this investigation provides a chemical characterization of real samples of "Rebites" freely obtained along Brazilian highways. Caffeine emerged as the predominant active compound, with its concentration determined by qNMR analysis. The notable presence of caffeine, combined with other stimulants, depressants, and hallucinogens, underscores the need for strict quality control measures regarding "Rebites" to safeguard public health.

Hollow-fiber liquid-phase microextraction and gas chromatography-mass spectrometry of barbiturates in whole blood samples.

Here, we present a method for measuring barbiturates (butalbital, secobarbital, pentobarbital, and phenobarbital) in whole blood samples. To accomplish these measurements, analytes were extracted by means of hollow-fiber liquid-phase microextraction in the three-phase mode. Hollow-fiber pores were filled with decanol, and a solution of sodium hydroxide (pH 13) was introduced into the lumen of the fiber (acceptor phase). The fiber was submersed in the acidified blood sample, and the system was subjected to an ultrasonic bath. After a 5 min extraction, the acceptor phase was withdrawn from the fiber and dried under a nitrogen stream. The residue was reconstituted with ethyl acetate and trimethylanilinium hydroxide. An aliquot of 1.0 µL of this solution was injected into the gas chromatograph/mass spectrometer, with the derivatization reaction occurring in the hot injector port (flash methylation). The method proved to be simple and rapid, and only a small amount of organic solvent (decanol) was needed for extraction. The detection limit was 0.5 µg/mL for all the analyzed barbiturates. The calibration curves were linear over the specified range (1.0 to 10.0 µg/mL). This method was successfully applied to postmortem samples (heart blood and femoral blood) collected from three deceased persons previously exposed to barbiturates.

Enzymatic-spectrophotometric determination of paraquat in urine samples: a method based on its toxic mechanism.

Paraquat is a broad-spectrum contact herbicide that has been encountered worldwide in several cases of accidental, homicidal, and suicidal poisonings. The pulmonary toxicity of this compound is related to the depletion of NADPH in the pneumocytes, which is continuously consumed by the reduction/oxidation of paraquat and reductase enzyme systems in the presence of O(2) (redox cycling). Based on this mechanism, an enzymatic-spectrophotometric method was developed for the determination of paraquat in urine samples. The velocity of NADPH consumption was monitored at 340 nm, every 10 s during 15 min. The velocity of NADPH oxidation correlated with the paraquat levels found in samples. The enzymatic-spectrophotometric method showed to be sensitive, making possible the detection of paraquat in urine samples at concentrations as low as 0.05 mg/L.

Gas chromatographic-mass spectrometric method for the determination of the herbicides paraquat and diquat in plasma and urine samples.

In the present work, a method was developed and optimized aiming to determinate the herbicides paraquat (PQ) and diquat (DQ) in human plasma and urine samples. An initial procedure of chemical reduction of the analytes by adding NaBH4 directly in the buffered samples (pH 8.0) was performed. This procedure was necessary to convert the quaternary ammonium substances into more volatile compounds for gas chromatographic analysis. The reduction compounds were extracted with C18 cartridges (solid-phase extraction). Ethyl paraquat (EPQ) was used as internal standard (IS). Gas chromatography-mass spectrometry (GC-MS) was used to identify and quantify the analytes in selected ion monitoring (SIM) mode. The limits of detection were 0.05 mg/l for both PQ and DQ. By using the weighted least squares linear regression (1/x1/2 for plasma and 1/y for urine), the accuracy of the analytical method was improved at the lower end of the calibration curve (from 0.1 to 50 mg/l; r>0.98). This method can be readily utilized as an important tool to confirm the suspicion of PQ and/or DQ poisoning and evaluate the extent of the intoxication.

Determination of low levels of benzodiazepines and their metabolites in urine by hollow-fiber liquid-phase microextraction (LPME) and gas chromatography-mass spectrometry (GC-MS).

In this study, it is shown a method for the determination of benzodiazepines and their main metabolites in urine samples by hollow-fiber liquid-phase microextraction (LPME) in the three-phase mode. Initially, the hydrolysis step was performed using 100 µL of sodium acetate 2.0 mol/L buffer solution (pH 4.5), 25 µL of ß-glucuronidase enzyme and incubation for 90 min at 55 °C. In parallel with hydrolysis, the LPME fiber (9 cm) was prepared. Its pores were filled with a mixture of dihexyl ether: 1-nonanol (9:1). Afterwards, a solution of 3.0 mol/L of HCl was introduced into the lumen of the fiber (acceptor phase). After hydrolysis, the fiber was submersed in the alkalinized urine (pH 10) containing 10% NaCl. Samples were then submitted to orbital shaking (2400 rpm) for 90 min. The acceptor phase was later withdrawn from the fiber, dried and the residue derivatized with trifluoroacetic anhydride (TFAA) for 10 min at 60 °C with further addition of N-methyl-N-tert-butyldimethylsilyltrifluoroacetamide containing 1% tert-butyldimethylchlorosilane (MTBSTFA) for 45 min at 90 °C followed by determination by gas chromatography-mass spectrometry (GC-MS). The calibration curves obtained showed linearity over the specified range, with a similar sensitivity to traditional techniques and a higher detection capability compared to most of the miniaturized methods described in the literature. The method has been developed and successfully validated and applied to urine samples from real cases of benzodiazepines intake.

Use of illicit drugs by truck drivers arriving at Paranaguá port terminal, Brazil.

OBJECTIVE: The purpose of this study was to estimate the prevalence of recent use of illicit drugs among truck drivers who had parked their vehicles at the terminal port in Paranaguá City at Paraná State, southern Brazil. METHODS: This cross-sectional study was part of a larger research project conducted among drivers at a regional Brazilian port. Data on professional characteristics, involvement in road traffic injuries, sleep, and use of alcohol and illicit drugs were collected using a questionnaire. Urine samples were collected and analyzed for amphetamines, cocaine, and cannabis using gas chromatography with mass spectrometric detection. RESULTS: Sixty-two drivers were included in the study. Toxicological analyses showed that 8.1 percent (95% confidence interval [CI], 2.7-17.8%) of the urine samples were positive for drugs (4.8% for cocaine, 1.6% for amphetamine, and 1.6% for both); 8.1 percent reported drug use during the preceding 30 days in the questionnaire and only one tested positive for the drug in the urine sample. No sample was positive for cannabinoids. In total, at least 14.5 percent (95% CI, 6.9-25.8%) had used illicit drugs during the preceding 30 days based on self-reports and urine testing. Drivers who reported involvement in traffic injuries the year before more often tested positive for drugs in biological samples (P <.05). CONCLUSIONS: This research provides preliminary evidence that the use of illicit stimulants was common among professional truck drivers transporting grain loads. Thus, actions are needed to reduce drug use among truck drivers in order to prevent drug-related road traffic injuries.

Detecting alcohol and illicit drugs in oral fluid samples collected from truck drivers in the state of São Paulo, Brazil.

OBJECTIVE: Alcohol and drug use by truck drivers is a current problem in Brazil. Though there is evidence that alcohol consumption is occurring in higher proportions, the use of stimulant drugs to avoid fatigue and to maintain the work schedule has also been reported. The purpose of this study was to estimate the incidence of alcohol and illicit drug use among truck drivers on São Paulo state roads. São Paulo is the most populous state in Brazil and has the largest industrial park and economic production in the country. METHODS: Data were assessed not only using a questionnaire but also, and more reliably, through toxicological analysis of oral fluid samples. Between the years 2002 and 2008, 1250 oral fluid samples were collected from truck drivers on the roads during morning hours. The samples were tested for the presence of alcohol, cocaine, tetrahydrocannabinol (THC), and amphetamine/methamphetamine. A previously published, validated gas chromatographic (gas chromatography-flame ionization detection and gas chromatography-mass spectrometry) method was applied to the samples for alcohol and drug detection. RESULTS: Of the total analyzed samples, 3.1 percent (n = 39) were positive: 1.44 percent (n = 18) were positive for alcohol, 0.64 percent (n = 8) for amphetamines, 0.56 percent (n = 7) for cocaine, and 0.40 percent (n = 5) for THC. In one case, cocaine and THC were detected. The results are indicative of the extent of alcohol and drug use by truck drivers in the state of São Paulo, Brazil. CONCLUSIONS: This research provides evidence that not only alcohol but also illicit drug use is a real problem among professional drivers. The use of these substances should be controlled to better promote safe driving conditions on Brazilian roads.

Determination of dimethyltryptamine and ß-carbolines (ayahuasca alkaloids) in plasma samples by LC-MS/MS.

BACKGROUND: Ayahuasca is a psychoactive plant beverage originally used by indigenous people throughout the Amazon Basin, long before its modern use by syncretic religious groups established in Brazil, the USA and European countries. The objective of this study was to develop a method for quantification of dimethyltryptamine and ß-carbolines in human plasma samples. RESULTS: The analytes were extracted by means of C18 cartridges and injected into LC-MS/MS, operated in positive ion mode and multiple reaction monitoring. The LOQs obtained for all analytes were below 0.5 ng/ml. By using the weighted least squares linear regression, the accuracy of the analytical method was improved at the lower end of the calibration curve (from 0.5 to 100 ng/ml; r(2)> 0.98). CONCLUSION: The method proved to be simple, rapid and useful to estimate administered doses for further pharmacological and toxicological investigations of ayahuasca exposure.