Microbial degradation products of lurasidone and their significance in postmortem toxicology.

Recent research reported that lurasidone degrades in unpreserved ante-mortem human whole blood inoculated with microorganisms known to dominate postmortem blood specimens. In vitro degradation occurred at a similar rate to risperidone, known to degrade in authentic postmortem specimens until below analytical detection limits. To identify the lurasidone degradation products formed, an Agilent 6520 liquid chromatograph quadrupole-time-of-flight mass spectrometer (LC-QTOF-MS) operating in auto-MS/MS mode was used. Numerous degradation products not previously reported in prior in vitro or in vivo pharmacokinetic studies or forced degradation studies were detected. Accurate mass data, mass fragmentation data, acetylation experiments, and a proposed mechanism of degradation analogous to risperidone supports initial identification of the major degradation product as N-debenzisothiazole-lurasidone (calculated m/z [M + H]+ = 360.2646). A standard was unavailable to conclusively confirm this identification. Retrospective data analysis of postmortem cases involving lurasidone identified the presence of the major degradation product in four of six cases where lurasidone was also detected. This finding is significant for toxicology laboratories screening for this drug in postmortem casework. The major postmortem lurasidone degradation product has consequently been added to the LC-QTOF-MS drug screen at Forensic Science SA (FSSA) to indicate postmortem lurasidone degradation in authentic postmortem blood specimens and as a marker of lurasidone administration in the event lurasidone is degraded to concentrations below detection limits.

In vitro degradation of ziprasidone in human whole blood.

A systematic study was performed into the degradation of ziprasidone in simulated postmortem blood. Fifteen potential degradation products not previously reported in the literature were observed. Four resulted from degradation in human blood, whereas the remaining products resulted from reaction with solvents: four from alkaline degradation, four from reaction with acetaldehyde, and three from reaction with acetone. To identify possible degradation products, a liquid chromatograph-diode array detector (LC-DAD) and liquid chromatograph quadrupole-time-of-flight mass spectrometer (LC-QTOF-MS) operating in auto-MS/MS mode were used. It was indicated from red-shifted UV-Vis spectra, accurate mass data, mass fragmentation data, and a deuteration experiment that the site of ziprasidone degradation, in the in vitro blood experiments, was the methylene carbon of the oxindole moiety. The major in vitro blood degradation products were proposed to be E/Z isomers of 3-ethylidene-ziprasidone. Further, another in vitro degradation product in microbially inoculated blood specimens was proposed to be 3-ethyl-ziprasidone. 3-Ethylidene-ziprasidone was hypothesized to form from the reaction of ziprasidone with acetaldehyde derived from the ethanol used to spike ziprasidone into the in vitro blood experiments. Data from two postmortem investigations were available for retrospective reanalysis. Attempts were made to detect degradation products of ziprasidone, but none were found.

Investigations into the stability of 17 psychoactive drugs in a "simulated postmortem blood" model.

In the postmortem environment, some drugs and metabolites may degrade due to microbial activity, even forming degradation products that are not produced in humans. Consequently, underestimation or overestimation of perimortem drug concentrations or even false negatives are possible when analyzing postmortem specimens. Therefore, understanding whether medications may be susceptible to microbial degradation is critical in order to ensure that reliable detection and quantitation of drugs and their degradation products is achieved in toxicology screening methods. In this study, a "simulated postmortem blood" model constructed of antemortem human whole blood inoculated with a broad population of human fecal microorganisms was used to investigate the stability of 17 antidepressant and antipsychotic drugs. Microbial communities present in the experiments were determined to be relevant to postmortem blood microorganisms by 16S rRNA sequencing analyses. After 7 days of exposure to the community at 37°C, drug stability was evaluated using liquid chromatography coupled with diode array detection (LC-DAD) and with quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Most of the investigated drugs were found to be stable in inoculated samples and noninoculated controls. However, the 1,2-benzisothiazole antipsychotics, ziprasidone and lurasidone, were found to degrade at a rate comparable with the known labile control, risperidone. In longer experiments (7 to 12 months), where specimens were stored at -20°C, 4°C, and ambient temperature, N-dealkylation degradation products were detected for many of the drugs, with greater formation in specimens stored at -20°C than at 4°C.

A Fatality Involving Furanylfentanyl and MMMP, with Presumptive Identification of Three MMMP Metabolites in Urine.

The prevalence of new psychoactive substances (NPS) on the illicit drug market continues to grow, with new analogs being routinely synthesized. Routes of administration for these compounds are also diversifying, and recent research has shown an increase in the incorporation of NPS into vaping liquids. Among the most commonly encountered NPS are the cathinone and fentanyl analogs. Fentanyl analogs in particular have been implicated in a significant number of deaths, usually in combination with other prescription and illicit drugs. We report the case of a 44-year-old male with a history of polysubstance abuse found deceased at his home address. Items located within the vicinity of the deceased were found to contain furanylfentanyl and 2-methyl-4'-(methylthio)-2-morpholinopropiophenone (MMMP also known as MTMP, MMTMP, Irgacure 907 and Caccure 907). Both of these compounds were detected in the post-mortem peripheral blood of the deceased: furanylfentanyl at 1.6 ng/mL and MMMP at 6.7 ng/mL. MMMP is an unrestricted, commercially available photo-initiator used in the printing and polymer industry, which structurally can be classed as a highly modified cathinone. Although MMMP has been found previously in drug seizures, this is the first fatality in which MMMP has been detected. A number of other prescription and illicit drugs were also detected in the blood. MMMP was not detected in the post-mortem urine; however three metabolites, beta-hydroxy-MMMP, beta-hydroxy-MMMP-sulfoxide and beta-hydroxy-MMMP-sulfone, were presumptively identified. The significance of MMMP to the cause of death is uncertain as its pharmacological and toxicological profile is unclear.

Bacterial degradation of risperidone and paliperidone in decomposing blood.

The stability of two benzisoxazole antipsychotics was determined in vitro in decomposing porcine blood inoculated with bacteria, utilizing a high-performance liquid chromatography with ultraviolet and fluorescence detection method for drug quantitation. Stability experiments for risperidone and paliperidone were conducted at 7, 20 and 37°C for 4 days using sterile and bacterially inoculated porcine blood. The drugs were stable in sterile blood at each temperature and in inoculated blood at 7°C, but degraded significantly in inoculated blood at 20 and 37°C. Complete loss occurred within 2 days when incubated at 37°C. The benzisoxazole-cleaved degradation products for both drugs were identified as 2-hydroxybenzoyl-risperidone and 2-hydroxybenzoyl-paliperidone utilizing liquid chromatography quadrupole-time-of-flight mass spectrometry and accurate mass measurements. The degradation products have been found in postmortem case studies, including one case where risperidone and paliperidone were not detected, indicating complete conversion can occur in situ.

Stability of serotonin-selective antidepressants in sterile and decomposing liver tissue.

It is well established that bacteria are capable of degrading selected drugs during decomposition. The aim of this study was to investigate the stability of several serotonin-selective reuptake inhibitor antidepressants and venlafaxine during putrefaction in porcine liver macerate inoculated with porcine cecal contents rich in bacteria. Blank liver matrices, sterile liver macerates, and sterile aqueous controls were included with the experiment performed for 57 days at 20°C under anaerobic conditions. A liquid chromatography/mass spectrometry method was developed for quantitative determination of the drugs investigated in both sterile and decomposed liver matrices. The method was found to encounter matrix effects not detected during the validation stage. Citalopram, paroxetine, sertraline, venlafaxine, and fluoxetine were found to be stable under the experimental conditions; however, fluvoxamine was found to be decreased by c. 50% over 57 days in bacterially inoculated liver macerate. This study suggests that fluvoxamine concentrations in cases with evidence of decomposition/putrefaction should be interpreted with extra caution.

The influence of putrefaction and sample storage on post-mortem toxicology results.

There are numerous biochemical and biological processes that occur after death that may have a significant influence on post-mortem drug concentrations. These processes may render the quantification of particular drugs unreliable, or even result in drugs being undetectable in some instances, despite the use of several methods. Problems may occur with changes in the drug concentration via bacterial degradation, residual tissue enzymatic activity, or via post-mortem redistribution from tissues of a higher to a lower concentration. Many analytical techniques can suffer from interferences due to co-extracted putrefactive compounds that mask or alter the way a drug is detected, depending on the analytical technique utilised. The following paper reviews problems associated with post-mortem drug concentration changes, and the significance of microbial influences during the post-mortem interval and sample storage.