Characterization and in vitro phase I microsomal metabolism of designer benzodiazepines: An update comprising flunitrazolam,norflurazepam, and 4'‐chlorodiazepam (Ro5–4864)

The number of newly appearing benzodiazepine derivatives on the new psychoactive substances (NPS) drug market has increased over the last couple of years totaling 23 ‘designer benzodiazepines’ monitored at the end of 2017 by the European Monitoring Centre for Drugs and Drug Addiction. In the present study, three benzodiazepines [flunitrazolam, norflurazepam, and 4′‐chlorodiazepam (Ro5–4864)] offered as ‘research chemicals' on the Internet were characterized and their main in vitro phase I metabolites tentatively identified after incubation with pooled human liver microsomes. For all compounds, the structural formula declared by the vendor was confirmed by gas chromatography?mass spectrometry (GC–MS), liquid chromatography?tandem mass spectrometry (LC MS/MS), liquid chromatography?quadrupole time of flight?mass spectrometry (LC?QTOF?MS) analysis and nuclear magnetic resonance (NMR) spectroscopy. The metabolic steps of flunitrazolam were monohydroxylation, dihydroxylation, and reduction of the nitro function. The detected in vitro phase I metabolites of norflurazepam were hydroxynorflurazepam and dihydroxynorflurazepam. 4’‐Chlorodiazepam biotransformation consisted of N‐dealkylation and hydroxylation. It has to be noted that 4′‐chlorodiazepam and its metabolites show almost identical LC–MS/MS fragmentation patterns to diclazepam and its metabolites (delorazepam, lormetazepam, and lorazepam), making a sufficient chromatographic separation inevitable. Sale of norflurazepam, the metabolite of the prescribed benzodiazepines flurazepam and fludiazepam, presents the risk of incorrect interpretation of analytical findings.     

Placebo responses and placebo effects in functional bowel disorders

The nature and determinants of the placebo response are widely unknown, as are the underlying psychological and biological mechanisms. Placebo response rates in functional bowel disorders (functional dyspepsia, irritable bowel syndrome) trials are similar to those in nonintestinal pain conditions and are comparable with other organic gastrointestinal diseases (duodenal ulcer, inflammatory bowel diseases). In this narrative review, different methodologies (meta-analyses, reanalyses, and experimental setups) are discussed that have been applied to the study of the placebo response in functional dyspepsia and the irritable bowel syndrome.     

A formula to calculate the standard liver volume in children and its application in pediatric liver transplantation

Due to a lack of available size‐matched liver grafts from children, most pediatric recipients are transplanted with technical variant grafts from adult donors. Size requirements for these grafts are not well defined, and consequences of mismatched graft sizes in pediatric liver transplantation are not known. Existing formulas for calculation of a standard liver volume are mostly derived from adults disregarding the age‐related percentual liver weight changes in children. In this study, we aimed to establish a formula for general use in children to calculate the standard liver volume. In a second step, the formula was applied in pediatric patients undergoing liver transplantation at our institution between 2000 and 2010 (n = 377). Analysis of a large number (n = 388) of autopsy data from children by regression analysis revealed a best fit for two formulas: “Formula 1,” children 0 to ≤1 year (n = 246): standard liver volume [ml] = ?143.062973 +4.274603051 * body length [cm] + 14.78817631 * body weight [kg]; “Formula 2,” children >1 to <16 years (n = 142): standard liver volume [ml] = ?20.2472281 + 3.339056437 * body length [cm] + 13.11312561 * body weight [kg]. In comparison with children receiving size‐matched organs, we found an elevated risk of liver graft failure in children transplanted with a small‐for‐size graft, whereas large‐for‐size organs seem to have no negative impact.     

5F-Cumyl-PINACA in ‘e-liquids’ for electronic cigarettes: comprehensive characterization of a new type of synthetic cannabinoid in a trendy product including investigations on the in vitro and in vivo phase I metabolism of 5F-Cumyl-PINACA and its non-fluorinated analog Cumyl-PINACA

Purpose

In recent years e-liquids used in electronic cigarettes have become an attractive alternative to smoking tobacco. A new trend is the use of e-liquids containing synthetic cannabinoids (SCs) instead of smoking cannabis or herbal mixtures laced with SCs. In the frame of a systematic monitoring of the online market of ‘legal high’ products, e-liquids from online retailers who also sell herbal blends were bought.

Methods

The products were analyzed by gas chromatography-mass spectrometry. In some of the e-liquids an unknown compound was detected which was identified as the SC 5F-Cumyl-PINACA (1-(5-fluoropentyl)-N-(2-phenylpropan-2-yl)-1H-indazole-3-carboxamide) by nuclear magnetic resonance analysis. To investigate the phase I metabolism of this new class of compounds, 5F-Cumyl-PINACA and its non-fluorinated analog Cumyl-PINACA were incubated with pooled human liver microsomes (pHLM). Cumyl-PINACA was additionally ingested orally (0.6 mg) by a volunteer in a controlled self-experiment. To assess the relative potency of Cumyl-PINACA a set of SCs were characterized using a cAMP assay.

Results

Metabolism of 5F-Cumyl-PINACA and Cumyl-PINACA showed similarities with AM-2201 and JWH-018. The main metabolites were formed by hydroxylation at the N-pentyl side chain. The main metabolites detected in the volunteer’s urine sample were the same as in the pHLM assay. All SCs tested with the cAMP assay were full agonists at the CB₁ receptor. Cumyl-PINACA was the most potent SC among the tested compounds and showed an EC₅₀ value of 0.06 nM.

Conclusions

The increasing popularity of e-liquids particularly among young people, and the extreme potency of the added SCs, pose a serious threat to public health. To our knowledge, this is the first report describing the tentative identification of human in vivo metabolites of Cumyl-PINACA and 5F-Cumyl-PINACA.

     

17Beta-estradiol downregulates Kupffer cell TLR4-dependent p38 MAPK pathway and normalizes inflammatory cytokine production following trauma-hemorrhage

Although studies have shown that 17beta-estradiol (estradiol) normalized Kupffer cell function following trauma-hemorrhage, the mechanism by which E2 maintains immune function remains unclear. Activation of Toll-like receptor 4 (TLR4) initiates an inflammatory cascade, involving activation of p38 mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K), and nuclear factor-kappaB (NF-kappaB). This leads to the release of proinflammatory cytokines. Thus, we hypothesized that the salutary effects of estradiol on Kupffer cell function following trauma-hemorrhage are mediated via negative regulation of TLR4-dependent p38 MAPK and NF-kappaB. TLR4 mutant (C3H/HeJ) and wild type (C3H/HeOuJ) mice were subjected to trauma-hemorrhage (mean BP 35+/-5 mmHg approximately 90 min, then resuscitation) or sham operation. Administration of estradiol following trauma-hemorrhage in wild type mice decreased Kupffer cell TLR4 expression as well as prevented the phosphorylation of p38 MAPK and NF-kappaB. This was accompanied by normalization of Kupffer cell production capacities of IL-6, TNF-alpha, macrophage inflammatory protein (MIP)-1alpha, and MIP-2 and the decrease in plasma cytokine levels. In contrast, TLR4 mutant mice did not exhibit the increase in Kupffer cell p38 MAPK and NF-kappaB activation, cytokine production, or the increase in circulating cytokine levels following trauma-hemorrhage. No difference was observed in activation of PI3K among groups. These results suggest that the protective effect of estradiol on Kupffer cell function is mediated via downregulation of TLR4-dependent p38 MAPK and NF-kappaB signaling following trauma-hemorrhage, which prevents the systemic release of cytokines.     

Investigation of the in vitro toxicological properties of the synthetic cannabimimetic drug CP-47,497-C8

Cannabicyclohexanol (CP-47,497-C8) is a representative of a group of cannabimimetic cyclohexylphenols which is added to herbal mixtures as a cannabis substitute since 2008. Although in the beginning CP-47,497-C8 was the main ingredient of “Spice” and similar products, it was partly replaced by aminoalkylindole-type cannabinoid receptor agonists like JWH-018, JWH-073 or JWH-250, but never completely disappeared from the market. Since information on its toxicological properties is scarce, we investigated the effects of the drug in human derived cell lines. The cytotoxic effects were studied in a panel of assays (SRB, XTT, LDHe and NR tests) in a buccal derived (TR146) and a liver derived (HepG2) cell line. The strongest effects were seen in the two former assays at levels ≥ 7.5 μM indicating that the compound interferes with protein synthesis and causes membrane damage. In additional comet assays, DNA damage was detected at levels ≥ 10 μM. Experiments with lesion specific enzymes showed that these effects are not due to oxidative damage of DNA bases. The negative findings obtained in Salmonella/microsome assays and the positive results of micronucleus tests with the cell lines indicate that the compound does not cause gene mutations but acts on the chromosomal level. In contrast to other synthetic cannabinoids, no indication for estrogenic/antiestrogenic properties was seen in a luciferase assay with bone marrow derived U2-OS cells. In conclusion, our findings show that the drug has only weak cytotoxic properties. However, the induction of chromosomal damage indicates that it may cause adverse effects in users due to its impact on the stability of the genetic material.