Post-mortem redistribution of three beta-blockers in the rabbit

Summary statistics for drugs and alcohol concentration recovered in post-mortem femoral blood in Western Switzerland

In post-mortem investigations of fatal intoxication, it is challenging to determine which drug(s) were responsible for the death, and which drugs did not. This study aims to provide post-mortem femoral blood drug levels in lethal intoxication and in post-mortem control cases, where the cause of death was other than intoxication. The reference values could assist in the interpretation of toxicological results in the routine casework. To this end, all post-mortem toxicological results in femoral blood from 2011 to 2017 in Western Switzerland were considered. A full autopsy with systematic toxicological analysis (STA) was conducted in all cases. Results take into account the cause of death classified into one of four categories (as published by Druid and colleagues): I) certified intoxication by one substance alone, IIa) certified intoxication by more than one substance, IIb) certified other causes of death with incapacitation due to drugs, and III) certified other causes of death without incapacitation due to drugs. This study includes 1 990 post-mortem cases where femoral blood was analysed. The material comprised 619 women (31%) and 1 371 men (69%) with a median age of 50 years. The concentrations of the 32 most frequently recorded substances as well as alcohol are discussed. These include 6 opioids and opiates, 3 antidepressants, 6 neuroleptics and hypnotics, 1 barbiturate, 11 benzodiazepines (and related drugs), 2 amphetamine-type stimulants, cocaine, paracetamol, and tetrahydrocannabinol (THC). The most common substances that caused intoxication alone were morphine, methadone, ethanol, tramadol, and cocaine. The post-mortem concentration ranges for all substance are categorized as I, IIa, IIb, or III. Statistical post-mortem reference concentrations for drugs are discussed and compared with previously published concentrations. This study shows that recording and classifying cases is time-consuming, but it is rewarding in a long-term perspective to achieve a more reliable information about fatal and non-fatal blood concentrations.

Fatal 4-MEC Intoxication: Case Report and Review of Literature

ABSTRACT

Synthetic cathinones are one of the major pharmacological families of new psychoactive substances and 4-methylethcathinone (4-MEC) has emerged in recent years as a recreational psychostimulant. We report a case of a 35-year-old man found dead and naked at home by his friend. Although no anatomic cause of death was observed at autopsy, toxicological analysis identified 4-MEC and hydroxyzine at therapeutic level (160 ng/mL). 4-Methylethcathinone was quantified in autopsy samples by a validated method consisting in liquid-liquid extraction and gas chromatography coupled to tandem mass spectrometry: peripheral blood, 14.6 μg/mL; cardiac blood, 43.4 μg/mL; urine, 619 μg/mL; vitreous humor, right 2.9 μg/mL and left 4.4 μg/mL; bile, 43.5 μg/mL; and gastric content, 28.2 μg/mL. The cause of death was 4-MEC intoxication and the manner of death could be either accidental or suicidal. The literature concerning 4-MEC was reviewed, focusing on distribution in classical postmortem matrices and 4-MEC metabolism and postmortem redistribution and stability.

Vitreous humor analysis for the detection of xenobiotics in forensic toxicology: a review

Vitreous humor (VH) is a gelatinous substance contained in the posterior chamber of the eye, playing a mechanical role in the eyeball. It has been the subject of numerous studies in various forensic applications, primarily for the assessment of postmortem interval and for postmortem chemical analysis. Since most of the xenobiotics present in the bloodstream are detected in VH after crossing the selective blood-retinal barrier, VH is an alternative matrix useful for forensic toxicology. VH analysis offers particular advantages over other biological matrices: it is less prone to postmortem redistribution, is easy to collect, has relatively few interfering compounds for the analytical process, and shows sample stability over time after death. The present study is an overview of VH physiology, drug transport and elimination. Collection, storage, analytical techniques and interpretation of results from qualitative and quantitative points of view are dealt with. The distribution of xenobiotics in VH samples is thus discussed and illustrated by a table reporting the concentrations of 106 drugs from more than 300 case reports. For this purpose, a survey was conducted of publications found in the MEDLINE database from 1969 through April 30, 2015.

Applying quantitative structure-activity relationship (QSAR) methodology for modeling postmortem redistribution of benzodiazepines and tricyclic antidepressants

Postmortem redistribution (PMR) constitutes a multifaceted process, which complicates the interpretation of drug concentrations by forensic toxicologists. The present study aimed to apply quantitative structure-activity relationship (QSAR) analysis for modeling PMR data of structurally related drugs, 10 benzodiazepines and 10 tricyclic antidepressants. For benzodiazepines, an adequate QSAR model was obtained (R(2) = 0.98, Q(2) = 0.88, RMSEE = 0.12), in which energy, ionization and molecular size exerted significant impact. For tricyclic antidepressants, an adequate QSAR model with slightly inferior statistics (R(2) = 0.95, Q(2) = 0.87, RMSEE = 0.29) was established after exclusion of maprotiline, in which energy parameters, basicity character and lipophilicity exerted significant contribution. Thus, QSAR analysis could be used as a complementary tool to provide an informative illustration of the contributing molecular, physicochemical and structural properties in PMR process. However, the complexity, non-static and time-dependent nature of PMR endpoints raises serious concerns whether QSAR methodology could predict the degree of redistribution, highlighting the need for animal-derived PMR data.

Postmortem redistribution of THC in the pig

To improve the knowledge of the postmortem redistribution of Δ(9)-tetrahydrocannabinol (THC), an animal model using the Large White pig has been developed, whereby 15 pigs received an intravenous injection of THC (200 µg/kg body weight) and were euthanized 2 h after administration. An autopsy was performed on three pigs immediately after being euthanized while the others were stored in supine position at ambient temperature for 6, 15, 24, or 48 h. THC concentration in blood from the vena cava decreased after death whereas left or right cardiac blood concentrations increased. No blood specimens collected from different sites of the carcasses adequately reflected the perimortem THC concentrations. The highest concentrations of THC at anytime were observed in lung tissue, and brain tissue seemed to present the most stable concentrations over time. This study can assist toxicologists in determining which specimens can, most appropriately, be used for interpretation of cannabinoid concentrations in postmortem specimens.

Post-mortem clinical pharmacology

Clinical pharmacology assumes that deductions can be made about the concentrations of drugs from a knowledge of the pharmacokinetic parameters in an individual; and that the effects are related to the measured concentration. Post-mortem changes render the assumptions of clinical pharmacology largely invalid, and make the interpretation of concentrations measured in post-mortem samples difficult or impossible. Qualitative tests can show the presence of substances that were not present in life, and can fail to detect substances that led to death. Quantitative analysis is subject to error in itself, and because post-mortem concentrations vary in largely unpredictable ways with the site and time of sampling, as a result of the phenomenon of post-mortem redistribution. Consequently, compilations of 'lethal concentrations' are misleading. There is a lack of adequate studies of the true relationship between fatal events and the concentrations that can be measured subsequently, but without such studies, clinical pharmacologists and others should be wary of interpreting post-mortem measurements.

Carisoprodol intoxications: a retrospective study of forensic autopsy material from 1992–2003

Carisoprodol is commonly prescribed as a centrally acting muscle relaxant, but it is also subject to abuse. The literature describing fatal intoxications with the drug is limited to a relatively small number of cases, and there are inconsistencies with regard to which concentration levels that are toxic. We therefore investigated all forensic autopsies at the Norwegian Institute of Public Health during the period 1992-2003 where carisoprodol was detected. The median concentrations of carisoprodol in intoxication with carisoprodol only or with only minor other analytical findings was 36 mg/l (range 8-65 mg/l; n=5). In the rest of the intoxications, the relevance of carisoprodol relative to the other drugs detected was variable (n=93). When the number of intoxications with carisoprodol each year were divided by the number of defined daily doses (DDD) sold, a fatal toxicity index between 5.6 and 6.9 deaths/1 million DDD was obtained. The total number of cases where carisoprodol was detected increased during the period studied, which correlated to sales figures for the drug. We conclude that carisoprodol can be fatal in concentrations below those indicated in some of the previously published literature. There were, however, only a small number of cases where the cause of death can be attributed to use of carisoprodol alone.

Postmortem distribution of 3,4-methylenedioxy-N,N-dimethyl-amphetamine (MDDM or MDDA) in a fatal MDMA overdose

In this manuscript, a newly identified compound, 3,4-methylenedioxy-N,N-dimethylamphetamine (MDDM or also called MDDA), was quantified. The substance was identified in the biological specimens of a 31-year-old man who died following a massive 3,4-methylenedioxymethamphetamine (MDMA) overdose. In addition, the postmortem distribution of the identified substance in various body fluids and tissues was evaluated. For MDDM quantitation, a formerly reported and validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method was adapted. The following quantitative results of the MDDM quantitation were obtained: Femoral blood, aorta ascendens, and right atrial blood contained 2.5, 21.7, and 11.6 ng MDDM/ml, respectively. In left and right pleural fluid and pericardial fluid, concentrations of 47.0, 21.7, and 31.9 ng/ml, respectively, were found. MDDM levels in urine, bile, and stomach contents were 42.4, 1,101, and 1,113 ng/ml, respectively. MDDM concentrations in lungs, liver, kidney, and left cardiac muscle ranged from 12.8 to 39.8 ng/g, whereas these levels were below the limit of quantitation (< LOQ) in right cardiac and iliopsoas muscle. In conclusion, for the first time, MDDM was unambiguously identified in a fatal MDMA overdose. MDDM was probably present as a synthesis by-product or impurity in the MDMA tablets, which were taken in a huge amount by the victim, or MDDM was ingested separately and prior to the MDMA overdose. A third option, i.e., the eventual formation of MDDM as a result of postmortem methylation of MDMA by formaldehyde, produced by putrefaction processes or during storage under frozen conditions, is also discussed. The MDDM levels, substantiated in various body fluids and tissues, are in line with the distribution established for other amphetamine derivatives and confirm that peripheral blood sampling, such as that of femoral blood, remains the "golden standard".