Comparative Study of Postmortem Concentrations of Antidepressants in Several Different Matrices.

Peripheral blood (PB) is considered to be the golden standard for measuring postmortem drug concentrations. In several cases, PB is however not available, but information regarding drug findings might still be crucial in order to determine the cause of death. Antidepressants are frequently detected in postmortem samples from forensic toxicology cases, but the literature investigating concentrations in other matrices than peripheral and heart blood is limited.We here describe a study for comparison of concentrations for a large number of different drugs in six different matrices. A total of 173 postmortem cases were included in the study material. The results from 44 cases with findings of antidepressants (amitriptyline/nortriptyline, citalopram, mianserin, mirtazapine, paroxetine, sertraline, trimipramine and venlafaxine) are presented in this article. Concentrations in peripheral and cardiac blood (CB), pericardial fluid (PF), two muscle samples and vitreous humour (VH) are compared. Ratios between concentrations in different matrices have also been compiled from available literature.All the investigated antidepressants were detected in all different matrices, and comparable concentration levels were found in the different matrices with a few exceptions. Concentrations in VH were generally lower than in the other matrices, and in a few cases with low concentrations in blood the antidepressants were not detected in VH. For most of the cases, ratios of 0.5-2 were found between concentration in PB and that in the other matrices. Some deviant concentrations where however found.This study shows that CB, PF, muscle and VH can provide important indications of the corresponding concentrations in PB when PB is not available.

Predominance of alcohol and illicit drugs among traffic accidents fatalities in an urban area of Brazil.

OBJECTIVE: The objective of this study was to determine the prevalence of alcohol and illicit drug use among victims of fatal traffic accidents in the Metropolitan Region of Vitória, Brazil, during the period 2011-2012. METHODS: Blood samples were collected and analyzed for the presence of drugs from 391 deceased victims of traffic crashes that occurred in the Metropolitan Region of Vitória, Brazil. The victims included drivers, passengers, and pedestrians. Sociodemographic variables such as age, gender, day of the week, and period of the year in which the accidents occurred were recorded. The analyses were performed by a gas chromatography-flame ionization method for alcohol and by a gas chromatography-mass spectrometry for amphetamines, cocaine, and cannabis. RESULTS: The results showed that 44.8% (n = 175) of all cases were positive for alcohol and/or illicit drugs. The detection of alcohol and/or drugs was more frequent in young males, aged 17 to 34, whose samples were positive in 46.8% of cases. Small differences among drivers, passengers, and pedestrians were observed (drivers = 45.9%, passengers = 46.4%, and pedestrians = 45.6%). In general, the most prevalent drug was alcohol, with 141 positive cases (36.1%), followed by cocaine, with 47 positive cases (12%). Amphetamines and cannabis had positivity rates of 4.1 and 4.3%, with 16 and 17 positive cases, respectively. The combined use of alcohol and other drugs was found in 36 cases (9.2%). Crack cocaine use was observed in 27.7% of the positive cases for cocaine. CONCLUSIONS: For the effective reduction of traffic accidents related to driving under influence of drugs (DUID), we suggest the intensification of enforcement actions against the use of alcohol by drivers, the definition of which illicit drugs should be surveyed, as well the cutoff values, the promotion of changing legislation to oblige drivers to provide samples for toxicological testing, and the establishment of public information programs and specific actions aimed at young drivers to promote behavioral changes.

Lethal poisonings with AH-7921 in combination with other substances.

AH-7921 is a synthetic µ-opioid agonist, approximately equipotent with morphine. We report the death of two young individuals after ingestion of AH-7921 in combination with other psychoactive drugs. In the first case a young man died shortly after ingesting Internet drugs. Toxicological analysis of post mortem peripheral blood revealed AH-7921 (0.43 mg/L), 2-FMA (0.0069 mg/L) and 3-MMC (0.0021 mg/L) as well as codeine (0.42 mg/L), codeine-6-glucuronide (0.77 mg/L) and acetaminophen (18.7 mg/L). The second case involved a young female found dead at home. The only positive finding at medicolegal autopsy was needle marks. Toxicological analysis revealed AH-7921 (0.33 mg/L), methoxetamine (MXE) (0.064 mg/L), etizolam (0.27 mg/L), phenazepam (1.33 mg/L), 7-aminonitrazepam (0.043 mg/L), diazepam (0.046 mg/L), nordiazepam (0.073 mg/L), and oxazepam (0.018 mg/L) in blood. In both cases intoxication with AH-7921 in combination with other psychoactive drugs was considered to be the cause of death.

A one-step extraction procedure for the screening of cocaine, amphetamines and cannabinoids in postmortem blood samples.

A gas chromatography-mass spectrometric (GC-MS) method was developed and validated for the simultaneous detection and quantification in postmortem whole blood samples of cocaine (COC), amphetamines (AMPs) and cannabis; the main drugs involved in cases of impaired driving in Brazil. The analytes were extracted by solid-phase extraction by means of Bond-Elute Certify cartridges, derivatized with N-methyl-N-(trimethylsilyl)trifluoroacetamide at 80°C for 30 min and analyzed by GC-MS. Linearity ranged from 10 to 500 ng/mL, except for ecgonine methyl ester, for which linearity ranged from 10 to 100 ng/mL. Inter- and intra-day imprecision ranged from 2.8 to 18.4% and from 1.5 to 14.9%, respectively. Accuracy values lay between 86.9 and 104.4%. The limit of quantitation for all drugs was 10 ng/mL and recoveries were >74% for all analytes, except for cannabinoids, which showed poor recovery (∼30%). The developed method was applied to real samples collected from deceased victims due to traffic accidents. These samples were selected according to the results obtained in immunoassay screening on collected urine samples. Five samples were positive for the presence of COC and metabolites, four samples were positive for cannabinoids, six samples were positive for AMPs and two samples were drug negative. Some samples were positive for more than one class of drug. Results obtained from whole blood samples showed good agreement with urine screening. The developed method proved capable of quantifying all three classes of drugs of abuse proposed in this study, through a one-step extraction procedure.

Simultaneous quantification of cocaine, amphetamines, opiates and cannabinoids in vitreous humor.

A GC-MS method for simultaneous analysis of cocaine (COC), amphetamines (AMPs), opiates, cannabinoids and their metabolites in vitreous humor (VH) was developed and fully validated. VH samples were extracted using solid phase extraction and injected into the GC-MS, using a selected ion monitoring mode. Linearity ranged from 10 to 1000 ng/mL; the exception was anhydroecgonine methyl ester (AEME), for which linearity ranged from 10 to 750 ng/mL. Inter-assay imprecision lay from 1.2 to 10.0%, intra-assay imprecision was <10.4% for all the analytes and accuracy ranged from 95.6 to 104.0%. An limit of quantitation for all drugs was 10 ng/mL and recoveries ranged from 70.4 to 100.1% for basic and neutral compounds; the acid compounds had poor recovery--<40%. The validated method was applied to 10 VH samples taken from individuals whose blood had screened positive for drugs of abuse. All the individuals screened positive for COC in the blood (seven samples) also had positive results in VH; COC concentration ranged from 30.81 to 283.97 ng/mL (mean 186.98 ng/mL) and benzoylecgonine concentration ranged from 11.47 to 460.98 ng/mL (mean 133.91 ng/mL). It was also noticed that, in five cases, cocaethylene was detected. AEME was also quantified in one case. The use of AMP detected by blood analysis was confirmed in the VH of one individual (24.31 ng/mL). However, samples taken from three individuals whose blood tested positive for carboxy-tetrahydrocannabinol presented negative results. The results demonstrated that VH is a suitable alternative biological sample to determine COC, AMPs, opiates and their metabolites.

D1 dopamine and NMDA receptors interactions in the medial prefrontal cortex: modulation of spatial working memory in rats.

Dopamine (DA) and N-methyl-D-aspartate (NMDA) receptors seem to be critically involved in working memory processing in the medial prefrontal cortex (mPFC). Effects of NMDA receptors blockade on dopamine D1 receptors activation in the mPFC on spatial working memory was investigated. Adult male Wistar rats, well trained in an eight-arm radial maze and bilaterally cannulated in the mPFC, received intracortical administrations of saline (SAL) or SKF-38393 (DA D1 receptor agonist) followed, 10 min later, by MK-801 (non-competitive NMDA receptor antagonist). They were tested in 1 h delayed tasks after 5 min of the second administration. SKF-38393 (0.56 and 1.8 microg) was disruptive to working memory, increasing significantly the number of errors in the 1 h post-delay performance when administered into the mPFC. MK-801, at doses with no significant effects alone (0.32 or 1.0 microg), reduced significantly the disruptive effect of 0.56 microg SKF-38393. These results showed that the disruptive effect of DA D(1) receptors activation in the mPFC on working memory was significantly reduced by an open-channel NMDA receptor blockade, suggesting that the processing of working memory in the mPFC involving DA D1 receptors depend, at least in part, of NMDA receptors activity in this cortical area.