Distribution of clomipramine, citalopram, midazolam, and metabolites in skeletal tissue after chronic dosing in rats

Post Mortem Analysis of Opioids and Metabolites in Skeletal Tissue

Every year, thousands of suspicious deaths are accounted for by an overdose of opioids. Occasionally all traditional matrices are unavailable due to decomposition. Skeletal tissue may pose a valid alternative. However, reference data on postmortem concentrations in bone tissue and bone marrow (BM) is sparse. Therefore, a liquid chromatography--tandem mass spectrometry method was developed and fully validated for the analysis of four opioids and two metabolites (tramadol, O-desmethyltramadol, morphine, fentanyl, norfentanyl, codeine) in bone tissue and BM. Sample preparation was performed using solid phase extraction (BM), methanolic extraction (bone) and a protein precipitation (whole blood). All validation parameters were successfully fulfilled. This method was applied to analyze 22 forensic cases involving opioids. All six opioids were proven to be detectable and quantifiable in all specimens sampled. When tramadol blood concentrations were correlated with bone concentrations, a linear trend could be detected. The same was seen between tramadol blood and BM concentration. A similar linear trend was seen when correlating codeine blood concentration with bone and BM concentration. Although some variability was detected, the same linear trend was seen for morphine. For fentanyl and norfentanyl, the sample size was too small to draw conclusions, regarding correlation. As far as the authors know this is the first-time fentanyl and norfentanyl are quantified in skeletal tissue. In conclusion, due to the absence of reference data for drugs in skeletal tissue, these findings are a step forward toward a more thorough understanding of drug concentration found in postmortem skeletal tissue.

Sample preparation of bone tissue for MALDI-MSI for forensic and (pre)clinical applications

In the past decades, matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) has been applied to a broad range of biological samples, e.g., forensics and preclinical samples. The use of MALDI-MSI for the analysis of bone tissue has been limited due to the insulating properties of the material but more importantly the absence of a proper sample preparation protocol for undecalcified bone tissue. Undecalcified sections are preferred to retain sample integrity as much as possible or to study the tissue-bone bio interface in particular. Here, we optimized the sample preparation protocol of undecalcified bone samples, aimed at both targeted and untargeted applications for forensic and preclinical applications, respectively. Different concentrations of gelatin and carboxymethyl cellulose (CMC) were tested as embedding materials. The composition of 20% gelatin and 7.5% CMC showed to support the tissue best while sectioning. Bone tissue has to be sectioned with a tungsten carbide knife in a longitudinal fashion, while the sections need to be supported with double-sided tapes to maintain the morphology of the tissue. The developed sectioning method was shown to be applicable on rat and mouse as well as human bone samples. Targeted (methadone and EDDP) as well as untargeted (unknown lipids) detection was demonstrated. DHB proved to be the most suitable matrix for the detection of methadone and EDDP in positive ion mode. The limit of detection (LOD) is estimated to approximately 50 pg/spot on bone tissue. The protocol was successfully applied to detect the presence of methadone and EDDP in a dosed rat femur and a dosed human clavicle. The best matrices for the untargeted detection of unknown lipids in mouse hind legs in positive ion mode were CHCA and DHB based on the number of tissue-specific peaks and signal-to-noise ratios. The developed and optimized sample preparation method, applicable on animal and human bones, opens the door for future forensic and (pre)clinical investigations.

Interpol review of toxicology 2016-2019

This review paper covers the forensic-relevant literature in toxicology from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20.Papers%202019.pdf.