Postmortem toxico-kinetics of co-proxamol

A comparative study of postmortem distribution and postmortem diffusion of tramadol in rabbits

In recent years, the cases of tramadol intoxication have become more frequent in many countries. However, most of the previous studies have been based on cases of tramadol intoxication, and the detailed information on the differences between postmortem distribution and diffusion of tramadol remains unclear. To investigate this issue systematically, we established a postmortem distribution model and two postmortem diffusion models. Then, gas chromatography-mass spectrometry (GC/MS) was used to measure the concentrations of tramadol in various biological specimens of fluids and tissues. In postmortem distribution, the results showed an uneven distribution of tramadol in various biological specimens, and the concentrations of tramadol in urine were significantly higher than those in other fluids. In postmortem diffusion, the results showed a dosage-dependent increase of tramadol concentration in most specimens; at all time points from 0.25 to 6 h after postmortem administration, the concentrations of tramadol in fluids were not significantly different from those in tissues, and the concentrations of tramadol in urine were lower than those in both tissues and other fluids in most time points. We recommend a quantitative examination of the specimens of both fluids and tissues to provide more evidence for the forensic identification, and the realization that there is a correlation between the concentrations of fluids and tissues is important for determining antemortem and postmortem administration of tramadol. This information can serve as ancillary data in inferring the contribution of a drug to death in cases of suspected tramadol poisoning.

Suitability of cardiac blood, brain tissue, and muscle tissue as alternative matrices for toxicological evaluation in postmortem cases

Drug concentrations in peripheral blood are often used to evaluate whether death was caused by drug intoxication. In some cases, peripheral blood is not available, and analytical results of alternative matrices should instead be used in the toxicological evaluation. However, reference concentrations of alternative matrices are few, which makes interpretation of results a challenge. In this study, concentrations of selected benzodiazepines, opioids, illicit drugs, and other commonly used drugs in postmortem femoral blood, cardiac blood, brain tissue, and muscle tissue are presented. Alternative matrix-to-femoral blood drug concentration ratios and correlations of blood and alternative matrix drug concentrations were calculated to examine which of the investigated alternative matrices were most suited to use for toxicological evaluation in cases where peripheral blood is not available. The results showed that concentrations in cardiac blood, brain tissue, and muscle tissue could be useful in the postmortem evaluation of most of the 19 selected analytes. In most cases, analytes were detected in all the alternative matrices. The median concentration ratios for the selected analytes in brain tissue, cardiac blood, and muscle tissue relative to femoral blood ranged from 0.57 to 3.42, 0.59 to 1.87, and 0.67 to 7.04, respectively. Overall, cardiac blood provided the concentrations most comparable with femoral blood concentrations, indicating that cardiac blood can be useful in cases where femoral blood is not available. However, the measured concentrations should be interpreted with caution.

Quantification of 16 QT-prolonging Drugs and Metabolites in Human Postmortem Blood and Cardiac Tissue Using UPLC-MS-MS

QT-prolonging compounds present a treatment risk in mentally ill patients. Knowledge of the concentration in the heart compared with blood is necessary to assess the cardiac toxicity of QT-prolonging compounds. To address this issue, this article presents a validated analytical method for the quantification of 16 QT-prolonging drugs (QTD) and metabolites in postmortem whole blood and postmortem cardiac tissue. Samples were prepared by protein precipitation and quantified using ultra-performance liquid chromatography coupled with tandem mass spectrometry. Deuterated internal standards were used. Validation results showed that the bias was ±15% and precision was ≤15% for all compounds in both matrices. The recovery ranged from 78.8 to 127.4%, and the matrix effect ranged from 61.0 to 128.7% across both matrices. The limit of detection and the lower limit of quantification were below the therapeutic concentrations of the prescription drugs. No noteworthy degradation during storage of the extracts was detected. The method was applied in five authentic cases of mentally ill patients. In conclusion, an analytical method was successfully developed and validated for the quantification of QTD in postmortem whole blood and cardiac tissue. To the best of the authors' knowledge, this article presents the first fully validated method for quantification of QTD in cardiac tissue.

Plasma vs heart tissue concentration in humans - literature data analysis of drugs distribution

Little is known about the uptake of drugs into the human heart, although it is of great importance nowadays, when science desires to predict tissue level behavior rather than to measure it. Although the drug concentration in cardiac tissue seems a better predictor for physiological and electrophysiological changes than its level in plasma, knowledge of this value is very limited. Tissue to plasma partition coefficients (Kp) come to rescue since they characterize the distribution of a drug among tissues as being one of the input parameters in physiologically based pharmacokinetic (PBPK) models. The article reviews cardiac surgery and forensic medical studies to provide a reference for drug concentrations in human cardiac tissue. Firstly, the focus is on whether a drug penetrates into heart tissue at a therapeutic level; the provided values refer to antibiotics, antifungals and anticancer drugs. Drugs that directly affect cardiomyocyte electrophysiology are another group of interest. Measured levels of amiodarone, digoxin, perhexiline and verapamil in different sites in human cardiac tissue where the compounds might meet ion channels, gives an insight into how these more lipophilic drugs penetrate the heart. Much data are derived from postmortem studies and they provide insight to the cardiac distribution of more than 200 drugs. The analysis depicts potential problems in defining the active concentration location, what may indirectly suggest multiple mechanisms involved in the drug distribution within the heart. Copyright © 2015 John Wiley & Sons, Ltd.

Fatal blood and tissue concentrations of more than 200 drugs

Fatal drug concentrations in body fluids and tissue samples are presented for more than 200 drugs and chemicals of toxicologic interest. Additionally, a reference list is added with more than 600 original papers concerning intoxications with a lethal outcome. The data can be helpful for the interpretation and plausibility control in own cases of intoxication. However, they should be used with caution, because use of drug data without sufficient knowledge about the patient or victim, the circumstances of the case, and about toxicokinetics and toxicodynamics might give a wrong interpretation in a special case.

Clocapramine-related fatality. Postmortem drug levels in multiple psychoactive drug poisoning

A suicide caused by ingestion of multiple psychoactive drugs is reported. A 42-year-old man with a history of psychosis was found dead in a blood pool in his room. The forensic autopsy revealed two stab wounds on his chest. However, these wounds could not explain the cause of death. Eighty-six tablets were found in his stomach. Four psychoactive drugs; clocapramine (CC), chlorpromazine (CP), promethazine (PM) and clotiazepam (CT) were detected in blood and tissues. The concentrations of CC, CP, PM and CT in the femoral vein (FV) blood were 0.39, 0.61, 1.23 and 0.09 microg/ml, respectively. The cause and manner of death were attributed to suicidal multiple psychoactive drug poisoning. Postmortem drug redistribution showed great site-dependent variations with the lowest level in the FV blood. Remarkable variations were observed in CC, CP and PM, but not in CT compared to other three drugs. The variations were dependent on the volume of distribution (Vd) of the drugs. Our human case has demonstrated drugs with higher Vd values showed higher degree of postmortem redistribution of the drug and vice versa.

Fatal combined intoxication with new antidepressants. Human cases and an experimental study of postmortem moclobemide redistribution

Three cases are presented in which death was caused by suicidal intoxication with moclobemide in combination with a selective serotonin reuptake inhibitor. Both antidepressant drug types are considered to be relatively safe with regard to lethal overdose. However, the combination may cause the serotonin syndrome, a condition with a high mortality rate. In one of the cases, there was clinical information consistent with the serotonin syndrome, in the two other cases, there was no information of the clinical course. Postmortem redistribution of the selective monoamine oxidase inhibitor moclobemide was investigated in a rat model. Postmortem concentrations in blood from the vena cava and the heart were found to be in good accordance with antemortem concentrations. Postmortem concentrations in vitreous humour and various tissues were also measured. The apparent volume of distribution was calculated to be 0.95 +/- 0.10 l/kg, which is in the same range as that reported in man.

Hemoglobin diffusion across a venous wall: an experimental study

The aim of this study was to investigate the permeation behavior of a large molecule through a venous wall; hemoglobin was chosen as a model substance. In vitro experiments were performed using a Chien-Valia diffusion chamber. Postmortem, hemolyzed, and fresh nonhemolyzed blood samples were investigated as permeants. Vein patches from vena cava inferior and vena jugularis interna were used as diffusion barriers. Applying this technique, extravasation of hemoglobin was detectable. The portion of hemoglobin molecules passing through the vascular wall depended on time, vein type, and graduation of hemolysis. The passage of hemoglobin across the wall of a large vein suggests intravascular changes in drug concentrations from postmortem blood samples not to be restricted on the unbound portion of the particular drug.

Postmortem distribution pattern of morphine and morphine glucuronides in heroin overdose

The postmortem distribution of morphine and its metabolites was investigated in four cases of heroin overdose to evaluate some of the factors that influence intravasal blood concentrations. Variables included were the chemical stability of morphine conjugates, hemoconcentration, incomplete distribution of the drug and diffusion processes. Blood samples from different sampling sites including the aorta, the infra- and suprarenal portion of the inferior vena cava, the superior vena cava, the femoral and subclavian veins, and the right and left ventricles were examined for morphine, morphine-3-glucuronide and morphine-6-glucuronide, hematocrit and water content. Drug concentrations were determined by HPLC based on the native fluorescence of the analytes. Morphine glucuronides proved to be stable for a time period of 72 h. The water content ranged from 65 to 83% and hematocrit values from 25 to 75%, and were seen as contributory factors to the dramatic differences observed for drug concentrations from different sampling sites. The differences could neither be attributed to incomplete distribution during life-time nor to a diffusion process following the different distribution volumes of morphine and its conjugates. A definite relationship between the ratio of the molar concentrations of morphine and its glucuronides, as assessed in pharmacokinetical studies after morphine dosing, could not be established. For a better understanding more cases and changes over time and tissue concentrations should be analysed.

Zopiclone poisoning: tissue distribution and potential for postmortem diffusion

Zopiclone is the first cyclopyrrolone hypnotic and is chemically unrelated to any existing drug. The authors studied the tissue distribution and postmortem redistribution of zopiclone in a fatal suicidal overdose. A 29-year-old female weighing 64 kg had cardiac blood ethanol 153 mg% and zopiclone blood concentrations in the range 0.9-2.0 microgram/ml in 10 distinct sampling sites. After 40 h at room temperature the range was 0.9-1.8 micrograms/ml in 15 samples. Portal venous blood and urine concentrations were 3.0 and 10.5 micrograms/ml, respectively. Tissue concentrations (microgram/g) were spleen 5.8, peri-renal fat 5.0, psoas muscle 3.3, brainstem 2.8, gastrocnemius muscle 1.9, myocardium 1.6, and kidney 1.7. Eight liver samples had concentrations in the range 0.5-4.9 micrograms/g, with highest concentrations in the left lobe and adjacent to the gallbladder, probably reflecting postmortem diffusion from gastric residue (700 ml, 55.1 micrograms/ml) and bile (14.1 micrograms/ml). Of six lung samples, paired upper and middle samples had concentrations in the range 2.1-2.3 micrograms/g, the right postero-basal 1.3 micrograms/g and the left postero-basal 3.4 micrograms/g. Drug concentration in putrefactive pleural fluid was also higher on the left (2.1 micrograms/ml) than the right (1.4 micrograms/ml), probably reflecting postmortem diffusion from gastric residue. The authors conclude that zopiclone showed little preferential concentration in solid organs and consequently has relatively stable postmortem blood concentrations, with little drug redistribution artefacts. Postmortem diffusion from gastric drug residue elevates drug levels in the left lobe of the liver and left lung lower lobe.

Postmortem release of amitriptyline from the lungs; a mechanism of postmortem drug redistribution

An experimental rat model was used to study postmortem redistribution of amitriptyline (AMI). Two hours after a subcutaneous injection with 20 mg of amitriptyline, the rats (n = 40) were anaesthetized and blood samples were drawn from the femoral vein and the heart. The rats were then sacrificed by CO2 and left at room temperature for either 0.1, 1, 2, 5, 24, 48, or 96 h. Postmortem blood samples from the heart and the inferior vena cava, and tissue samples from the lungs, heart, liver, right kidney, thigh muscle, the wall of the abdominal vena cava and brain were analyzed by high performance liquid chromatography. A significant increase was observed within 2 h postmortem in heart blood and later also in blood from the inferior vena cava. At 96 h postmortem the concentration increase was 4.4 +/- 0.5-fold (P < 0.01) and 3.0 +/- 1.1-fold (P < 0.05) as compared to the antemortem values observed in heart blood and blood from the inferior vena cava, respectively (mean +/- SEM). In the lungs there was a fall in the concentration of AMI from 148 +/- 16.7 mumol/kg at 0.1 h to 49.1 +/- 7.8 mumol/kg at 96 h postmortem (P < 0.01). In the vessel wall of the abdominal vena cava there was also a significant fall in drug concentration, while in heart muscle and liver an increase in drug concentration was observed. In animals where the lungs were removed agonally (n = 7), the drug concentration in heart blood had increased significantly less at 2 h postmortem.(ABSTRACT TRUNCATED AT 250 WORDS)

Postmortem changes in blood tranylcypromine concentration: competing redistribution and degradation effects

Site and temporal changes in tranylcypromine (TCP) and lithium concentrations in blood were studied in a human poisoning case. Blood samples from peripheral vessels and six central vessels were obtained at 0, 6, 24, 48 and 72 h after starting the autopsy. Nine tissue samples were obtained on completion. TCP showed preferential concentration in liver (2.21 micrograms/g) and brainstem (2.46 micrograms/g). There was a moderate post mortem redistribution phenomenon with TCP concentrations lowest in peripheral blood (0.17 micrograms/ml) at 0 h and highest in central vessels at 24 h (0.52 micrograms/ml). At 72 h blood TCP concentrations fell below those at 0 time but the samples showed marked putrefactive changes. Control blood samples spiked with TCP and incubated for 48 h at 37 degrees C showed a 58% fall in drug concentration. By contrast with TCP, lithium, which has a small Vd (0.8 l/kg) and is chemically stable, did not show this pattern of change in blood concentration. The site and temporal differences in TCP concentration in blood can be explained by the competing effects of post mortem redistribution and drug degradation. Redistribution is an early post mortem phenomenon characterised by diffusion, along a concentration gradient, from drug reservoirs in solid organs into adjacent blood vessels. Drug degradation is a later phenomenon associated with putrefactive change.

Diffusion as a mechanism of postmortem drug redistribution: an experimental study in rats

In some cases of drug overdose there is a reservoir of unabsorbed drug in the stomach and gut. Furthermore, agonal aspiration might establish a second reservoir in the lungs. Two experimental rat models were used to study if diffusion from these reservoirs could contribute to the phenomenon of postmortem drug redistribution. Overnight fasted rats were sacrificed by CO2 and 75 mg of amitriptyline (AMI) was administered by a gastric tube. In the first series (n = 19), the tubes were removed after AMI administration. In the second series (n = 17), the trachea was ligated and cut prior to drug administration to prevent airways contamination. The rats were left at room temperature on their back for a period of 5, 10, 24, 48, 96 up to 192 h and samples of heart blood, blood from the inferior vena cava, tissue samples from heart, lungs, different liver lobes, kidney and psoas muscle were taken. In both series of rats we observed that as early as 5 h postmortem increasing concentrations of amitriptyline were found in the liver lobes lying closest to the stomach. In rats where the trachea was not ligated, drug contamination of the lungs also resulted in an increase in drug concentration within 5 h in heart blood and heart muscle. In rats where the trachea had been ligated, amitriptyline was found in the lungs after 96 h postmortem. The main metabolite nortriptyline was also detected.(ABSTRACT TRUNCATED AT 250 WORDS)