Postmortem drug analysis: analytical and toxicological aspects

A pilot study on post-mortem determination of drug abuse on dental tissues

BACKGROUND

Post-mortem toxicology constantly deals with the research of reliable alternative matrices to be applied in case of highly damaged corpses (such us carbonized, skeletonized, human remains, etc.). Teeth represent a promising alternative matrix since dental tissues are endowed by different features, resistance and stability after death.

SCOPE

Since scant literature reported on the pharmacokinetics and mechanism of incorporation of xenobiotics into dental tissues, this pilot research aims to investigate whether in the pulp can be detected the same substances found in blood in drug related death cases. Secondly, the study is addressed to disclose the possible deposit of drugs in dental hard tissues (dentine and/or enamel), thus contributing to reconstruct the drug abuse history (timing, e.g.).

MATERIALS AND METHODS

The study experimented with a novel method to separately analyse dental enamel, dentin, and pulp, applied to 10 teeth collected during autopsies of drug-related deaths along with blood and hair samples for classic toxicological analyses. Each tooth was prepared by "pulverization technique" and then analysed by gas chromatography paired with mass spectrometry (GC-MS) and ultra high performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC/HR-MS) for searching cocaine, opiates, and metabolites. The results were then compared with those obtained from blood and hair samples.

RESULTS

Preliminary results demonstrated that teeth differ from any other classic matrix (blood and hairs) since the qualitative correspondence of the detected substances between pulp and blood as well as dental hard tissues and hair suggests that they can be useful in post-mortem evaluation as a unique matrix for both acute and chronic assumptions of drugs. The mechanism of accumulation of substances in mineralized dental tissues emerged the most significant result, being influenced by the type of molecule and the method of assumption. The main limitation of this study is the limited availability of the sample and the absence of anamnestic information of the time, rates and method of drug assumption during life. Further research is necessary to systematically investigate the distribution of different substances within the different tissues of the tooth.

Comparison of Comprehensive Screening Results in Postmortem Blood and Brain Tissue by UHPLC-QTOF-MS

Alternative specimens collected during autopsies can be valuable in postmortem toxicology in cases where peripheral blood is not available. The applicability of brain tissue as an alternative matrix for drug screening by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry was investigated in this study. Results of the 50 most frequently detected drugs and metabolites of toxicological interest in blood and brain tissue samples from 1,719 autopsy cases were compared. Examination of the results in paired blood and brain tissue samples revealed that the two matrices were in general comparable, as the majority of the 50 analytes were observed in a high number of the examined cases in both blood and brain tissue. This demonstrates the potential of brain tissue as an alternative matrix for drug screening in postmortem toxicology or as a secondary matrix for confirmation.

Fatal poisonings involving clozapine: A 16-year review of Australian coronial investigations

OBJECTIVE

Concerns about intentional and unintentional poisoning present a barrier to wider use of clozapine in treatment-resistant schizophrenia. The objective of this study was to investigate decedent demographics and trends in fatal poisonings in Australia involving clozapine.

METHODS

This was a retrospective case series of all fatal drug toxicity reported to an Australian coroner between 1 May 2000 and 31 December 2016 where toxicological analysis detected clozapine. Cases were identified using the National Coronial Information System. Demographics extracted included age and gender of the decedent, year and location of death, cause and manner of death and drugs detected in post-mortem samples.

RESULTS

There were 278 poisoning deaths where clozapine was detected in toxicological analyses. Three-quarters of all cases (n = 207) involved men and the median age at death was 38.5 years (interquartile range: 16 years). Three-quarters of the deaths occurred in the home. Overall, 15.8% of deaths were deemed intentional, 57.5% unintentional and 24.5% of unknown intent. While the annual number of intentional self-poisonings remained constant with <5 per year, the overall number of fatalities increased due to an increase in unintentional poisonings. Multiple drug toxicity was reported in 55.0% of cases and clozapine alone in 45.0% of cases. The most common co-reported medications were antidepressants, benzodiazepines and opioids detected in 47.1%, 44.4% and 41.2% of multiple drug toxicities, respectively.

CONCLUSION

This was the first Australia-wide review of all fatal drug poisonings reported to a coroner involving clozapine. Fatalities were most common in men and occurred at home. Multiple drug toxicity generally involved psychotropic, sedative or opioid analgesic medications. Despite increasing clozapine use, rates of intentional poisoning have remained constant and low. Developing a better knowledge of unintentional fatalities presents an opportunity to minimise harm.

Monte Carlo optimization method based QSAR modeling of postmortem redistribution of structurally diverse drugs

The Monte Carlo optimization method was employed for the development of the QSAR model for the prediction for postmortem redistribution of structurally diverse drugs.

Unexpected results found in larvae samples from two postmortem forensic cases

Purpose

In forensics, entomological specimens can be used as additional/alternative matrices to detect xenobiotics when human specimens are limited in their application. Despite some advantages over implementing putrefied human remains, most medico-legal laboratories do not include entomotoxicological procedures as routine analytical methods. We thus applied two authentic cases to evaluate necrophagous larvae’s potential as complementary matrices for toxicological analysis after extensive postmortem decomposition.

Methods

Larvae and postmortem human samples, including hair, stomach contents, pericardial fluid, liver, lung, and skeletal muscle, were collected at autopsy. Samples were analyzed by liquid chromatography–tandem mass spectrometry and liquid chromatography–quadrupole time-of-flight mass spectrometry for pharmaceutical substances, illicit drugs, and new psychoactive substances, including synthetic cannabinoids, benzodiazepines, new synthetic opioids, and stimulants.

Results

Nearly all substances detected in human specimens, including several benzodiazepines and synthetic cannabinoids, were also detected in larvae. Surprisingly, some drugs, including the new psychoactive substances EAM-2201 and U-47700, were found exclusively in larvae and hair. The benzodiazepine etizolam was detected only in liver, lungs, and stomach contents, possibly resulting from characteristic tissue distribution in humans and/or larvae.

Conclusions

Antemortem external hair contamination with synthetic cannabinoids from side-stream smoke and postmortem hair contamination with substances in putrefaction fluids can be supposed in these cases. Our findings suggest that supplementary information can indeed be gained from analyzing larvae additional to those human specimens that are typically used for toxicological analysis after extensive postmortem decomposition. Nevertheless, these results represent merely two cases, requiring in-depth studies to determine whether such findings can identify acute intoxications as possible causes of death.

The Future of Analytical and Interpretative Toxicology: Where are We Going and How Do We Get There?

(Forensic) toxicology has faced many challenges, both analytically and interpretatively, especially in relation to an increase in potential drugs of interest. Analytical toxicology and its application to medicine and forensic science have progressed rapidly within the past centuries. Technological innovations have enabled detection of more substances with increasing sensitivity in a variety of matrices. Our understanding of the effects (both intended and unintended) have also increased along with determination and degree of toxicity. However, it is clear there is even more to understand and consider. The analytical focus has been on typical matrices such as blood and urine but other matrices could further increase our understanding, especially in postmortem (PM) situations. Within this context, the role of PM changes and potential redistribution of drugs requires further research and identification of markers of its occurrence and extent. Whilst instrumentation has improved, in the future, nanotechnology may play a role in selective and sensitive analysis as well as bioassays. Toxicologists often only have an advisory impact on pre-analytical and pre-interpretative considerations. The collection of appropriate samples at the right time in an appropriate way as well as obtaining sufficient circumstance background is paramount in ensuring an effective analytical strategy to provide useful results that can be interpreted within context. Nevertheless, key interpretative considerations such as pharmacogenomics and drug-drug interactions as well as determination of tolerance remain and in the future, analytical confirmation of an individual's metabolic profile may support a personalized medicine and judicial approach. This should be supported by the compilation and appropriate application of drug data pursuant to the situation. Specifically, in PM circumstances, data pertaining to where a drug was not/may have been/was contributory will be beneficial with associated pathological considerations. This article describes the challenges faced within toxicology and discusses progress to a future where they are being addressed.

Drug detection in decomposed cadavers confirms testimonial evidence in a case of serial homicides

Toxicology investigation on human's buried dead bodies is a rare and challenging task in the forensic field. As requested by the Judicial Authority, this work aimed to verify testimonial evidence that emerged during a criminal investigation involving multiple murder cases. The statements indicated an improper medical administration of one or more alleged drugs (propofol, morphine, diazepam, and midazolam) which presumably caused the deaths. Since the supposed crimes took place several years before, the task of the present work was to obtain results to support the charges. The analyses involved 18 biological samples taken from four exhumed bodies, three of which were female and one male, each buried in a different date and mode. Each sample was treated with specific purification and extraction techniques (LLE - SPE) after the addition of the deuterated analogs of the searched analytes (propofol-d17, morphine-d3, diazepam-d5, midazolam-d4) as internal standards. Afterwards, the extracts were subjected to qualitative analysis by gas chromatography-mass spectrometry-Electron Impact (GC/MS - EI), both in full scan and SIM mode. Propofol, morphine, and diazepam were identified in the corpses. It supports testimonials that were administered just before the deaths occurred.

Methadone, Buprenorphine, Oxycodone, Fentanyl, and Tramadol in Multiple Postmortem Matrices

Peripheral blood (PB) concentrations are generally preferred for postmortem toxicological interpretation, but some autopsy cases may lack blood for sampling due to decomposition or large traumas, etc. In such cases, other tissues or bodily fluids must be sampled; however, limited information exists on postmortem concentrations in matrices other than blood. Pericardial fluid (PF), muscle and vitreous humor (VH) have been suggested as alternatives to blood, but only a few studies have investigated the detection of opioids in these matrices. In this study, we aimed to investigate the detection of methadone, buprenorphine, oxycodone, fentanyl and tramadol in postmortem samples of PF, skeletal muscle and VH, in addition to PB and cardiac blood and if drug concentrations in these alternative matrices were comparable to those in PB and thereby useful for interpretation. In most of the 54 included cases, only one opioid was detected. Methadone, oxycodone, fentanyl and tramadol were detected in all of the alternative matrices in almost all cases, while buprenorphine was detected less often. For methadone, the concentrations in the alternative matrices, except in VH, were relatively similar to those in PB. Larger variations in concentrations were found for buprenorphine, oxycodone and tramadol. Quantitative analyses appeared useful for fentanyl, in all of the alternative matrices, but only four cases were included. Toxicological analyses of opioids in these alternative postmortem matrices can be useful for detection, but quantitative results must be interpreted with caution.

Toxicological Investigations in a Death Involving 2,5-Dimethoxy-4-Chloamphetamine (DOC) Performed on an Exhumed Body

During a party in another country, several adults sniffed a powder presented as being lysergic acid diethylamide (LSD). The next morning, two subjects, including a French citizen, were found dead. After a body examination that concluded that the death was due to respiratory and cardiac collapses, the French citizen's corpse was returned to France and buried. Four years later, the body was exhumed, and an autopsy that did not reveal traumatic injury was performed. During the autopsy, biological specimens were collected. A comprehensive toxicological screening, followed by confirmation using ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS-MS) revealed the presence of 2,5-dimethoxy-4-chloamphetamine (DOC) in all specimens: liver (99 ng/g), spleen (28 ng/g), bone (14 ng/g), lung (15 ng/g) and pubic hair (32 pg/mg). No other drug, including pharmaceuticals and drugs of abuse were identified, but the circumstances of specimen collection can influence drug stability. Literature survey about DOC stability in biological material did not contribute in interpretation as there is no data dealing with storage for about 4 years before quantitative analysis. A stability study was performed at the laboratory. Blank blood was spiked with DOC at 1 mg/L, stored at + 4°C and -20°C and regularly tested over 6 months. The percentages of concentration remaining from the initial concentration of DOC stored for 6 months at + 4°C and -20°C were 53% and 59%, respectively. To characterize the metabolite(s) of DOC, the drug was incubated with a pool of human hepatic microsomes and the cofactors required to ensure the functioning of the main phase I enzymes. The incubation media were analyzed by liquid chromatography (LC) coupled to high-resolution mass spectrometry (MS), and the results showed hydroxy-DOC. However, the hydroxy-metabolite was not identified in the liver or spleen of the subject. Although the French pathologist considered that it was more likely than not a toxic death, it is difficult to attribute the death to DOC alone, as it was impossible to test for ethanol and other chemically instable drugs. This case presents original data, which can be useful to increase the knowledge in designer drug toxicity.

Determination of drugs in exhumed liver and brain tissue after over 9 years of burial by liquid chromatography-tandem mass spectrometry-Part 2: Benzodiazepines, opioids, and further drugs

In this publication, benzodiazepines, opioids, and further drugs were analyzed in exhumed brain and liver tissue samples in 116 cases (total) after 9.5-16.5 years of burial. Solid phase extraction followed by liquid chromatography-tandem mass spectrometry was applied. Data from literature is listed summarizing the detectability of the presented analytes after a certain time of burial. In our study, 60% of the analyzed benzodiazepines, 100% of the opioids, and 82% of further drugs were detectable. Only the benzodiazepines lorazepam, nitrazepam, flunitrazepam, and its metabolite norflunitrazepam, and the drugs butylscopolamine, metronidazole, and omeprazole were not detectable at all. Percentage of positive findings (total, and separately for brain and liver tissue) and postmortem period are listed for each analyte. Correlation of detectability depending on postmortem period and condition of tissue are presented exemplarily for midazolam. No substantial correlation was observed. Despite a long time of burial, most benzodiazepines, opioids, and further drugs were detectable in the examined tissue samples. Our results may be a good support for future exhumations in which toxicological analyses are relevant.

Real-time drug detection using a diathermic knife combined to rapid evaporative ionisation mass spectrometry

Fast, accurate and sensitive detection of drugs in human tissue is of crucial importance in an investigation of a suspicious death. Here, we aimed to screen cocaine, diazepam, methadone and morphine in post-mortem muscle samples without sample preparation and in quasi-real time using rapid evaporative ionisation mass spectrometry (REIMS). REIMS enables the online MS analysis of vapours generated from tissue dissection by a diathermic knife. Human muscle samples were soaked in solutions of 4 drugs at different concentrations and multiple incubation times to check the feasibility of REIMS for this innovative application. Muscle samples soaked in blank saline were used as a control. The classification model was able to distinguish between 30 μg g^-1 cocaine (m/z 304.2), 200 μg g^-1 morphine (m/z 286.2), 10 μg g^-1 methadone (m/z 310.2) and 10 μg g^-1 muscle of diazepam (m/z 285.1). REIMS tandem MS confirmed that the mass peaks that contributed to the class separation, originated from the drugs of interest. As a proof-of-concept, a forensic case muscle sample from a methadone overdose was investigated using REIMS. Here, using our classification model, the recognition software was able to detect methadone, demonstrating that the REIMS method opens new possibilities in forensic toxicology and during autopsy, leading to faster crime solving and decreased costs.

Analytical considerations for postmortem metabolomics using GC-high-resolution MS

Metabolomics studies that aim to qualitatively and quantitatively characterize the entirety of small endogenous biomolecules in an organism are widely conducted in the clinical setting. They also become more and more popular in the field of forensics (toxicology), e.g., to assist in postmortem investigations by objective postmortem interval estimation. However, other issues in postmortem toxicology, such as the phenomenon of (time-dependent) postmortem redistribution, have not yet been tackled by metabolomics studies. Hence, the aim of the current study was to develop an (un)targeted gas chromatography-high-resolution mass spectrometry-based method for endogenous metabolites as a tool for large-scale (un)targeted human postmortem metabolomics investigations (e.g., to objectively assess PMR) with thorough analytical evaluation of this method to ensure fitness-to-purpose in terms of reliability and robustness. This was achieved by using a targeted metabolite subset (n = 56) and a targeted processing workflow. Evaluation experiments have shown that using an artificial matrix (revised simulated body fluid (rSBF) + 5% bovine serum albumin (BSA)) for calibration purposes, all parameters lay within the scope of the method (sensitivity, selectivity, calibration model, accuracy, precision, processed sample stability, and extraction efficiency). When applying this method to large-scale studies, samples should be run in randomized order if analysis time is expected to exceed 18-24 h and potential biomarkers that are found with this method should be verified by a specialized, targeted method (e.g., by using standard addition in authentic matrix for quantification purposes). Overall, the current method can be successfully used for conduction of time-dependent postmortem metabolomics investigations. Graphical abstract.

Cocaine toxicological findings in cases of violent death in Sao Paulo city - Brazil

Violence is a dreadful phenomenon spread throughout the world, resulting in unfortunate events that can ultimately cause death. It is known that some countries play a much worrying role in this scenario than others. Brazil is one of them. The present work has focused on identifying the use of cocaine in 105 postmortem cases arriving at the Institute of Legal Medicine of Sao Paulo (IML-SP), the largest Brazilian city. Both blood and hair samples have been analyzed through ultra-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) in order to distinguish between recent or chronic cocaine use. The purpose of this work was to evaluate the proportion of cocaine use amongst violent individuals whose violence has ultimately led to their death. In order to do so, two previous methods, validated in-house, based on methanolic extraction for hair and protein precipitation for blood, have been used for this purpose and the final residue was analyzed through UPLC-ESI-MS/MS system. When looking at the demographics from the 105 postmortem cases analyzed, the results have shown the most critical age range to be between 18 and 25 years old and the least frequent between 37 and 45 years old. Gender wise, a rather extreme difference was found as 97 of the individuals were men and finally, considering the manner of death, the four-category criteria established appear to be fairly similar with 34 cases related to general violence and risk behavior, 26 to drug abuse suspicion, 23 to homicide resulting from opposition to police intervention and 22 to possible suicide.

Increasing rates of quetiapine overdose, misuse, and mortality in Victoria, Australia

BACKGROUND

Quetiapine is misused due to its anxiolytic and hedonic effects and has been associated with deliberate self-harm. This study analyzed quetiapine-related calls to the Victorian Poisons Information Centre (VPIC), coronial data from Victorian Institute of Forensic Medicine (VIFM) and prescribed data from the Pharmaceutical Benefits Scheme (PBS) to determine current trends in overdose, misuse and mortality.

METHODS

This was a retrospective review of multiple databases. Calls to VPIC and coronial data from the VIFM were reviewed from 2006 to 2016. PBS prescription data from 2000 to 2015 was obtained from the Australian Statistics on Medicines website.

RESULTS

VPIC data indicated a 6-fold increase in the number of quetiapine-related calls over the 11-year period of which most were overdose-related (77%). Overdose and misuse calls increased by 6-fold and 6.6-fold, respectively. Coronial data also indicated a rise in quetiapine-related harm; a 7.4-fold increase in quetiapine-related deaths was recorded for the same period. Similarly, Australian PBS data showed that quetiapine prescriptions increased 285-fold since 2000. There was a significant positive correlation between the increase in prescribing and overdose (r = 0.75, p < 0.001), and prescribing and mortality (r = 0.82, p < 0.01).

CONCLUSIONS

This study revealed an increasing trend of misuse, non-fatal and fatal overdoses in Victoria over the last decade. The increasing rates of prescriptions in Australia and thus increased quetiapine availability are likely to have contributed to increased poisoning and mortality. Further research is warranted to explore the reasons behind increased prescribing, including off-label use.

Forensic entomotoxicology revisited-towards professional standardisation of study designs

Forensic entomotoxicology is the use of insects as evidence of whether a toxicant is present in an environment such as a corpse, river or landscape. The earliest overtly forensic study was published in 1977, and since then, at least 63 papers have been published, most of them focused on the detection of toxicants in insects or on effects of toxicants on diverse insect indicator taxa. A comprehensive review of the published literature revealed various inconsistencies between studies that could be addressed by introducing standard protocols for such studies. These protocols could include selecting widespread and common model organisms (such as Lucilia sericata, Calliphora vicina, Chrysomya megacephala and Dermestes maculatus) and model toxicants (e.g. morphine and amitriptyline) to build up comparative databases; developing a standard matrix for use as a feeding substrate; setting guidelines for statistically adequate sample sizes; and deploying more sophisticated analytical methods from the general field of toxicology. Future studies should then be aimed at refining standardised protocols to improve experimental results, and make these results more comparable between studies.

Pharmacokinetics of heroin and its metabolites in vitreous humor and blood in a living pig model

Vitreous humor (VH) is an alternative matrix for drug analysis in forensic toxicology. However, little is known about the distribution of xenobiotics, such as opioids, into VH in living organisms. The aim of this study was to simultaneously measure heroin and metabolite concentrations in blood and VH after injection of heroin in a living pig model. Six pigs were under non-opioid anesthesia during the surgical operation and experiment. Ocular microdialysis was used to acquire dialysate from VH, and a venous catheter was used for blood sampling. Twenty milligrams of heroin was injected intravenously with subsequent sampling of blood and dialysate for 6 h. The samples were analyzed by ultra-performance liquid chromatography–tandem mass spectrometry. Heroin was not detected in VH; 6-monoacetylmorphine (6-MAM) and morphine were first detected in VH after 60 min. The morphine concentration in VH thereafter increased throughout the experimental period. For 6-MAM, C_max was reached after 230 min in VH. In blood, 6-MAM reached C_max after 0.5 min, with a subsequent biphasic elimination phase. The blood and VH 6-MAM concentrations reached equilibrium after 2 h. In blood, morphine reached C_max after 4.3 min, with a subsequent slower elimination than 6-MAM. The blood and VH morphine concentrations were in equilibrium about 6 h after injection of heroin. In conclusion, both 6-MAM and morphine showed slow transport into VH; detection of 6-MAM in VH did not necessarily reflect a recent intake of heroin. Because postmortem changes are expected to be small in VH, these experimental results could assist the interpretation of heroin deaths.

Impacts of Pharmaceuticals on Terrestrial Wildlife

Essentially ubiquitous in our environment, residues of human and veterinary pharmaceuticals somewhat paradoxically represent an emerging and increasing risk to wild biota. Whilst in recent years a great deal of analytical effort has been expended to quantify the presence of many pharmaceutical contaminants, especially in freshwater systems, our real understanding of the risks posed to most clades of wildlife, aquatic and terrestrial alike, still lags behind. In particular, relevant field-based studies regarding possible chronic impacts in higher terrestrial wildlife (birds, mammals, reptiles, etc.) remain all too scarce. Yet, for example, over the past two decades Old World Gyps vultures on the Indian subcontinent have been virtually extirpated due to non-target exposure to a single synthetic pharmaceutical compound, diclofenac (a non-steroidal anti-inflammatory drug). Here, we highlight and discuss the myriad possible exposure routes to terrestrial wildlife, consider the analytical and monitoring approaches that are already in use or that could be used in future research, and reflect upon a selection of legislative approaches currently being applied to identified terrestrial impacts. Finally, with the ultimate aim of encouraging further applied ecotoxicology-based research in this emerging field, we highlight several priorities for future inquiry, with special emphasis on non-target effects in previously overlooked but potentially vulnerable or highly representative clades of wildlife exposed within environmentally relevant, real-world scenarios.

Development and validation of a LC/MS method for the determination of Δ(9)-tetrahydrocannabinol and 11-carboxy-Δ(9)-tetrahydrocannabinol in the larvae of the blowfly Lucilia sericata: Forensic applications

In a number of forensic toxicological cases, Δ(9)-tetrahydrocannabinol (THC) and its metabolite 11-carboxy-delta-9-tetrahydrocannabinol (THCA) are frequently considered as contributor factors to the event. To that, a liquid chromatographic mass spectrometric method is described for the identification and quantitation of THC and its metabolite THCA in the forensically important larvae of L. sericata. Larvae of Lucilia sericata were fortified with varying concentrations of THC and THCA covering the calibration range between 10 and 500pg/mg. For the isolation of the analytes from larvae, several extraction techniques were evaluated and finally liquid-liquid extraction under acidic pH was selected using hexane-ethyl acetate (50:50, v/v) as extraction solvent. For the chromatographic separation, a Waters Symmetry® C18 analytical column was used while the mobile phase was acetonitrile-ammonium acetate (2mM) (30:70, v/v). The detection was performed using electrospray ionization source in negative mode (ESI-) and the selected ions monitored were m/z 313 for THC and m/z 343 for THCA. The proposed method which is simple and sufficiently sensitive for the detection of THC and THCA even in a single larva sampling, assisted the investigation of a forensic case.

A simple extraction and LC-MS/MS approach for the screening and identification of over 100 analytes in eight different matrices

In the present study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) multi-analyte approach using one single work-up approach in whole blood, plasma, serum, post-mortem blood, liver tissue, gastric content, hair, and urine was developed for fast target screening and reliable identification of 130 analytes often requested in clinical and forensic toxicology. Samples (500 μL each) of whole blood, plasma, serum, post-mortem blood, tissue (homogenized 1 + 4 with water), as well as 3 g of distilled gastric contents, 1 mL of urine, or 20 mg of pulverized hair were extracted at different pH values with an diethyl ether-ethyl acetate mixture (1:1). Separation and identification were performed using LC-QTRAP with electrospray ionization in positive mode. For identification 1 scheduled multi-reaction-mode (sMRM) method with 390 transitions was developed covering benzodiazepines, Z-drugs, antidepressants, neuroleptics, opioids, new synthetic drugs, and phosphodiesterase type 5 inhibitors. For positive sMRM transitions with intensities exceeding 5000 cps, dependent scans (EPI scan collision energy, 35 eV, collision energy spread, 15 eV) were performed for library search using our in-house library. The method was developed with respect to selectivity, matrix effects, recovery, process efficiency, limit of detection, and applicability. The simple work-up procedure was suitable for all biosamples with exception of urine in respect to low concentrated analytes, which showed median recovery values of 59%. The method was selective for 130 analytes in all 8 biosamples. For 106 analytes, the limit of detection in whole blood, plasma, and serum was lower than the lowest therapeutic concentration listed in blood level lists.

A review of the use of clozapine levels to guide treatment and determine cause of death

OBJECTIVE

To review the literature to examine the use of clozapine levels to (i) guide therapy and prevent toxicity in clinical care and (ii) determine cause of death in post-mortem examination of patients who were treated with clozapine.

METHODS

MEDLINE was searched in December 2010 using the following keywords: 'clozapine levels', 'clozapine and toxicity', 'clozapine and death', 'clozapine and mortality' and 'post-mortem redistribution'. Data was also collected from the 2010 MIMS Annual.

RESULTS

The literature reported significant variation in clozapine levels attained with any given dose, and considerable variability in the clinical response achieved at any given clozapine level. The lowest effective clozapine levels ranged from 250 to 550 µg/L, while the recommended upper limit to prevent toxicity varied from 600 to 2000 µg/L. There was minimal correlation between clozapine levels and side effects, with the exception of sedation, hypotension and seizure activity. The risk of seizures increased with plasma clozapine levels greater than 600 µg/L or rapid upward titration. In addition to prescribed dose, there are many factors that influence plasma clozapine levels. After death, the process of post-mortem drug redistribution resulted in 3.00 to 4.89 times increases in clozapine levels in central blood vessels and 1.5 fold increases in peripheral vessels compared to ante-mortem levels.

CONCLUSIONS

The exact range of clozapine levels that corresponds to toxicity remains unclear. However, levels between 350 µg/L and 1000 µg/L achieved with gradual upward titration are more likely to be effective and less likely to cause toxicity. Ongoing clozapine level monitoring is indicated, especially when (i) prescribing higher doses (> 600 mg/day) of clozapine, (ii) there has been a change in a patient's concomitant pharmacotherapy or cigarette use and (iii) there has been a suboptimal response to treatment. The use of post-mortem clozapine levels to determine clozapine toxicity as a cause of death is unreliable.

Principles and procedures in forensic toxicology

The principles and procedures employed in a modern forensic toxicology lab are detailed in this review. Aspects of Behavioral and Postmortem toxicology, including certification of analysts and accreditation of labs, chain of custody requirements, typical testing services provided, rationale for specimen selection, and principles of quality assurance are discussed. Interpretation of toxicology results in postmortem specimens requires the toxicologist and pathologist to be cognizant of drug-drug interactions, drug polymorphisms and pharmacogenomics, the gross signs of toxic pathology, postmortem redistribution, confirmation of systemic toxicity in suspected overdoses, the possibility of developed tolerance, and the effects of decomposition on drug concentration.

Sample treatment based on extraction techniques in biological matrices

The importance of sample preparation methods as the first stage in bioanalysis is described. In this article, the sample preparation concept and strategies will be discussed, along with the requirements for good sample preparation. The most widely used sample preparation methods in the pharmaceutical industry are presented; for example, the need for same-day rotation of results from large numbers of biological samples in pharmaceutical industry makes high throughput bioanalysis more essential. In this article, high-throughput sample preparation techniques are presented; examples are given of the extraction and concentration of analytes from biological matrices, including protein precipitation, solid-phase extraction, liquid–liquid extraction and microextraction-related techniques. Finally, the potential role of selective extraction methods, including molecular imprinted phases, is considered.

Collection of biological samples in forensic toxicology

Forensic toxicology is the study and practice of the application of toxicology to the purposes of the law. The relevance of any finding is determined, in the first instance, by the nature and integrity of the specimen(s) submitted for analysis. This means that there are several specific challenges to select and collect specimens for ante-mortem and post-mortem toxicology investigation. Post-mortem specimens may be numerous and can endow some special difficulties compared to clinical specimens, namely those resulting from autolytic and putrefactive changes. Storage stability is also an important issue to be considered during the pre-analytic phase, since its consideration should facilitate the assessment of sample quality and the analytical result obtained from that sample. The knowledge on degradation mechanisms and methods to increase storage stability may enable the forensic toxicologist to circumvent possible difficulties. Therefore, advantages and limitations of specimen preservation procedures are thoroughfully discussed in this review. Presently, harmonized protocols for sampling in suspected intoxications would have obvious utility. In the present article an overview is given on sampling procedures for routinely collected specimens as well as on alternative specimens that may provide additional information on the route and timing of exposure to a specific xenobiotic. Last, but not least, a discussion on possible bias that can influence the interpretation of toxicological results is provided. This comprehensive review article is intented as a significant help for forensic toxicologists to accomplish their frequently overwhelming mission.

Drug poisoning deaths in Sweden show a predominance of ethanol in mono-intoxications, adverse drug-alcohol interactions and poly-drug use

Over a 10-year period (1998-2007) all deaths in Sweden classified by forensic pathologists as fatal drug poisonings (N = 6894) were retrieved from a toxicology database (TOXBASE) belonging to the National Board of Forensic Medicine. The deaths were further classified as suicides N = 2288 (33%), undetermined N = 2260 (33%) and accidental N = 2346 (34%). The average age (± SD) of all victims was 49.1 ± 15.9 years and men 47.4 ± 15.6 years were 5-year younger than women 52.2 ± 15.8 years (p < 0.01). Most of the deceased (78%) were poly-drug users although a single drug (mono-intoxications) was found in 22% of all poisoning deaths (p < 0.001). The number of drugs in blood samples varied from 1 to 12 with a median of 3-4 per case. Mono-intoxication deaths were mostly ethanol-related (N = 976) and the mean and median blood-alcohol concentration (BAC) was 3.06 g/L and 3.10 g/L, respectively. The BAC decreased as the number of additional drugs in blood increased from 2.15 g/L with one drug to 1.25 g/L with 6 or more drugs. The mean (median) concentrations of non-alcohol drugs in mono-intoxication deaths were morphine (N = 93) 0.5mg/L (0.2mg/L), amphetamine (N = 39) 2.0mg/L (1.2mg/L), dextropropoxyphene (N = 33) 3.9 mg/L (2.9 mg/L), dihydro-propiomazine (N = 32) 1.6 mg/L (1.0mg/L) and 7-amino-flunitrazepam (N = 28), 0.4 mg/L (0.3mg/L). Elevated blood morphine in these poisoning deaths mostly reflected abuse of heroin as verified by finding 6-monoacetyl morphine (6-MAM) in the blood samples. When investigating drug poisoning deaths a comprehensive toxicological analysis is essential although the results do not reveal the extent of prior exposure to drugs or the development of pharmacological tolerance. The concentrations of drugs determined in post-mortem blood are one element in the case. The autopsy report, the police investigation, the findings at the scene and eye-witness statements should all be carefully considered when the cause and manner of death are determined.

Forensic toxicology

Forensic toxicology has developed as a forensic science in recent years and is now widely used to assist in death investigations, in civil and criminal matters involving drug use, in drugs of abuse testing in correctional settings and custodial medicine, in road and workplace safety, in matters involving environmental pollution, as well as in sports doping. Drugs most commonly targeted include amphetamines, benzodiazepines, cannabis, cocaine and the opiates, but can be any other illicit substance or almost any over-the-counter or prescribed drug, as well as poisons available to the community. The discipline requires high level skills in analytical techniques with a solid knowledge of pharmacology and pharmacokinetics. Modern techniques rely heavily on immunoassay screening analyses and mass spectrometry (MS) for confirmatory analyses using either high-performance liquid chromatography or gas chromatography as the separation technique. Tandem MS has become more and more popular compared to single-stage MS. It is essential that analytical systems are fully validated and fit for the purpose and the assay batches are monitored with quality controls. External proficiency programs monitor both the assay and the personnel performing the work. For a laboratory to perform optimally, it is vital that the circumstances and context of the case are known and the laboratory understands the limitations of the analytical systems used, including drug stability. Drugs and poisons can change concentration postmortem due to poor or unequal quality of blood and other specimens, anaerobic metabolism and redistribution. The latter provides the largest handicap in the interpretation of postmortem results.