Distribution of quetiapine and metabolites in biological fluids and tissues

Vitreous humor in the forensic toxicology of quetiapine and its metabolites

PURPOSE

Τhe aim of the present study was to investigate the use of vitreous humor as an alternative biological material in forensic toxicology for the determination of quetiapine, 7-hydroxy-quetiapine, and nor-quetiapine. The distribution of these substances in vitreous humor was studied by determining and correlating their concentrations in vitreous humor with the respective concentrations in blood.

METHODS

During this study, a method for the determination of these substances was developed, validated and applied to postmortem samples obtained from 16 relative forensic cases. The sample preparation procedure included the isolation of the analytes from vitreous humor and blood samples using solid-phase extraction, with Bond Elut LRC C18 columns followed by derivatization with BSTFA with 1% TMCS prior to GC/MS analysis.

RESULTS

The developed method is characterized by a dynamic range of 10.0-1000.0 ng/mL (R2 ≥ 0.991) for the three substances, with a limit of detection and quantification of 3.0 and 10.0 ng/mL, respectively. Accuracy and precision were below 8.09% and 8.99%, respectively, for both biological materials, while absolute recovery for the three substances was greater than 81%. According to the results, quetiapine, 7-hydroxy-quetiapine, and nor-quetiapine are easily distributed in vitreous humor.

CONCLUSION

The results of the study indicate the usefulness of vitreous humor in toxicological analysis for the determination of these substances, especially when the traditional biological materials are not available. The levels of quetiapine and its metabolites in vitreous humor as well as the vitreous humor to blood concentration ratios can provide important information for a more thorough toxicological investigation of forensic cases.

Quetiapine-Related Deaths: In Search of a Surrogate Endpoint

Quetiapine is a second-generation antipsychotic drug available for two and half decades. Due to increased misuse, prescription outside the approved indications, and availability on the black market, it is being encountered in medicolegal autopsies more frequently. For instance, it has been linked to increased mortality rates, most likely due to its adverse effects on the cardiovascular system. Its pharmacokinetic features and significant postmortem redistribution challenge traditional sampling in forensic toxicology. Therefore, a systematic literature review was performed, inclusive of PubMed, the Web of Science-core collection, and the Scopus databases; articles were screened for the terms "quetiapine", "death", and "autopsy" to reevaluate each matrix used as a surrogate endpoint in the forensic toxicology of quetiapine-related deaths. Ultimately, this review considers the results of five studies that were well presented (more than two matrices, data available for all analyses, for instance). The highest quetiapine concentrations were usually measured in the liver tissue. As interpreted by their authors, the results of the considered studies showed a strong correlation between some matrices, but, unfortunately, the studies presented models with poor goodness of fit. The distribution of quetiapine in distinct body compartments/tissues showed no statistically significant relationship with the length of the postmortem interval. Furthermore, this study did not confirm the anecdotal correlation of peripheral blood concentrations with skeletal muscle concentrations. Otherwise, there was no consistency regarding selecting an endpoint for analysis.

Recent Advances in Analytical Techniques for Antidepressants Determination in Complex Biological Matrices: A Review

Depression is one of the most prevalent but severe of mental disorders, affecting thousands of individuals across the globe. Depression, in its most extreme form, may result in self-harm and an increased likelihood of suicide. Antidepressant drugs are first-line medications to treat mental disorders. Unfortunately, these medications are also prescribed for other in- and off-label conditions, such as deficit/hyperactivity disorders, attention disorders, migraine, smoking cessation, eating disorders, fibromyalgia, pain, and insomnia. This results in an increase in the use of antidepressant medications, leading to clinical and forensic overdose cases that could be either accidental or deliberate. The findings revealed that people who used antidepressants had a 33% greater chance of dying sooner than expected, compared to those who did not take the medications. Analytical techniques for precisely identifying and detecting antidepressants and their metabolic products in a variety of biological matrices are greatly needed to be developed and made available. Hence, this study attempts to discuss various analytical techniques used to identify and determine antidepressants in various biological matrices, which include urine, blood, oral fluid (saliva), and tissues, which are commonly encountered in clinical and forensic science laboratories.

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.

Antipsychotic-Related Fatal Poisoning, England and Wales, 1993-2019: The Impact of Second-Generation Antipsychotics

BACKGROUND

Deaths from antipsychotic (AP) poisoning have increased in England and Wales despite restriction of the use of thioridazine in 2000.

METHODS

We analyzed data from the Office for National Statistics drug-related death database, England and Wales, 1993-2019, to investigate fatal AP poisoning.

RESULTS

There were 2286 deaths (62% male patients). Annual numbers of intentional AP-related fatal poisonings (suicides) were relatively stable (1993, 35; 2019, 44; median, 44; range, 30-60). Intentional overdose deaths involving clozapine (96 male, 25 female) increased from 1 in 1994 to 5 in 2003 and have since remained relatively constant (median, 6; range, 3-10 per annum). Unintentional second-generation AP-related fatal poisonings have increased steadily since 1998, featuring in 828 (74%) of all unintentional, AP-related fatal poisonings in the period studied (2019, 89%). There were 181 unintentional clozapine-related deaths, (107 [59%] alone without other drugs ± alcohol) as compared with 291 quetiapine-related deaths (86 [30%] alone without other drugs ± alcohol) and 314 unintentional olanzapine-related deaths (77 [25%] alone without other drugs ± alcohol). Some 75% of all unintentional clozapine- and olanzapine-related deaths were of male patients (78% and 73%, respectively) as compared with 58% of unintentional quetiapine-related fatal poisonings. Clozapine now features prominently in intentional and in unintentional AP-related fatal poisoning in England and Wales. Deaths of male patients predominate in both categories. There were also 77 and 86 deaths attributed to unintentional poisoning with olanzapine and with quetiapine, respectively, in the absence of other drugs.

CONCLUSIONS

More effort is needed to prevent unintentional deaths not only from clozapine but also from olanzapine and quetiapine.

Time- and Site-Dependent Postmortem Redistribution of Antidepressants and Neuroleptics in Blood and Alternative Matrices

Postmortem redistribution (PMR) leads to challenges in postmortem case interpretation. Particularly antidepressants and neuroleptics are expected to undergo PMR based on their physico-chemical properties. For the current study, time- and site-dependent PMR of 20 antidepressants and neuroleptics were investigated in humans (authentic cases); five of which are discussed in detail (citalopram, mirtazapine, quetiapine, risperidone and venlafaxine) along with two metabolites (9-OH-risperidone and O-desmethylvenlafaxine). Blood [femoral (pB) and heart blood (HB)] and tissue biopsy samples (lung, kidney, liver, spleen, thigh muscle and adipose tissue) were collected upon admission to the institute utilizing a computed tomography-guided sample collection workflow (t1). Approximately 24 h later (t2; mean 23 ± 9.3 h), samples from the same body regions were collected manually. Liquid chromatography-tandem mass spectrometry was used for quantification. Most antidepressants and neuroleptics showed significant time-dependent concentration changes indicating the occurrence of PMR. For the first time, two phases of redistribution in pB for quetiapine were proposed (concentration decreases in the early postmortem phase, followed by concentration increases) and contrasting existing literature, both concentration increases and decreases in pB overtime were observed for risperidone and 9-OH-risperidone. Venlafaxine and its metabolite only showed minimal concentration changes, while citalopram exhibited a trend for concentration increases and mirtazapine for concentration decreases in pB overtime. Based on time-dependent tissue data, passive diffusion processes along the muscle-to-pB, liver-to-HB and lung-to-HB concentration gradients could be proposed along with bacterial degradation. Overall, no case interpretation had to be adjusted, which suggests that PMR changes of antidepressants and neuroleptics do not seem to be relevant for forensic case interpretation within the 24 h period that was investigated. However, limitations of the current study (e.g., temperature-controlled storage of the bodies) could have led to an underestimation of occurring postmortem changes, hence, interpretation of postmortem results should always be conducted with care, considering PMR phenomena and inter-individual variability.