Clearance In Human Microsomes Research Articles

Liver-Selective Imidazolopyrazine Mitochondrial Uncoupler SHD865 Reverses Adiposity and Glucose Intolerance in Mice.

Excess body fat is a risk factor for metabolic diseases and is a leading preventable cause of morbidity and mortality worldwide. There is a strong need to find new treatments that decrease the burden of obesity and lower the risk of obesity-related comorbidities including cardiovascular disease and type 2 diabetes. Pharmacologic mitochondrial uncouplers represent a potential treatment for obesity through their ability to increase nutrient oxidation. Herein, we report the in vitro and in vivo characterization of compound SHD865, the first compound to be studied in vivo in a newly discovered class of imidazolopyrazine mitochondrial uncouplers. SHD865 is a derivative of the furazanopyrazine uncoupler BAM15. SHD865 is a milder mitochondrial uncoupler than BAM15 that results in a lower maximal respiration rate. In a mouse model of diet-induced adiposity, six-week treatment with SHD865 completely restored normal body composition and glucose tolerance to levels like those of chow-fed controls without altering food intake. SHD865 treatment also corrected liver steatosis and plasma hyperlipidemia to normal levels comparable with chow-fed controls. SHD865 has maximal oral bioavailability in rats and slow clearance in human microsomes and hepatocytes. Collectively, these data identify the potential of imidazolopyrazine mitochondrial uncouplers as drug candidates for the treatment of obesity-related disorders.

Abstract 296: Structure-based and property-based drug design of AZD5305, a highly selective PARP1 inhibitor and trapper

Abstract Since the approval of olaparib in 2014 for BRCA mutated (BRCAm) ovarian cancer, many PARP inhibitors have been developed and have seen widespread success. However, as a class, these drugs are not without adverse events which have limited their ability to be combined with chemotherapy. Most first generation PARP inhibitors were developed and optimized before the concept of PARP1-DNA trapping was discovered as the mechanism by which PARP inhibitors exert their synthetic lethal effects on BRCAm cells. Moreover, the first generation PARP inhibitors were not optimized for selectivity across the PARP family potentially driving undesirable side effects, including intestinal toxicity from tankyrase inhibition or hematological toxicity from PARP2 inhibition. With this in mind, we set out to discover a best-in-class, second generation PARP inhibitor that was highly selective for PARP1 over the other 16 members of the PARP family, as well as a highly potent PARP1-DNA trapper. PARP1 and PARP2 have a highly similar amino acid sequence, and most of the residues around the nicotinamide binding site are identical. However, there are some key residue differences in the helical domain which serves a regulator of the nicotinamide binding pocket. The publication of NMS-P118 in 2015 by Nerviano Medical Sciences showed that a highly selective PARP1 inhibitor could be found. This work inspired us to screen an extensive list of previously reported PARP inhibitors for selectivity against PARP2 and we found that FR257516 met the selectivity criteria as previously reported, but lacked the ability to trap PARP1 to DNA and hence lacked any activity in a cell colony formation assay in DLD-1 BRCA2-/- cells. Using parallel chemistry to generate diverse analogs, X-ray crystallography to enable structure-based design, and exploration of multiple nicotinamide mimetic cores, we were able to generate lead compound AZ4554, which was a PARP1 selective PARP1-DNA trapper with potent activity in BRCAm cells. Using concepts of property-based drug design, we were able to optimize lead compound AZ4554 into candidate drug AZD5305, making key improvements in secondary pharmacology, including reducing hERG activity, and intrinsic clearance in human microsomes through the introduction of polar atoms to lower logD without compromising permeability or oral bioavailability. AZD5305 is a highly selective binder of PARP1 over PARP2 and other PARP enzymes by fluorescence polarization, surface plasmon resonance, and single molecule spectroscopy. It is highly potent against DLD-1 BRCA2-/- cells, while sparing isogenic BRCA WT cells. The secondary pharmacology of AZD5305 is remarkably clean, with hERG activity >40 µM. AZD5305 has a very favorable pre-clinical PK profile, low predicted human dose, and has shown efficacy in an MDA-MB-436 mouse xenograft model. Citation Format: Sudhir Hande, Amber Balazs, Sébastien L. Degorce, Kevin Embrey, Avipsa Ghosh, Sonja J. Gill, Anders Gunnarsson, Giuditta Illuzzi, Jordan Lane, Carrie Larner, Elisabetta Leo, Andrew Madin, Lisa McWilliams, Mark J. O'Connor, Jonathan Orme, Fiona Pachl, Martin Packer, Andy Pike, Philip Rawlins, Marianne Schimpl, Anna D. Staniszewska, Andrew Zhang, Xiaolan Zheng, Jeffrey W. Johannes. Structure-based and property-based drug design of AZD5305, a highly selective PARP1 inhibitor and trapper [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 296.

3-Benzyl-1,3-oxazolidin-2-ones as mGluR2 positive allosteric modulators: Hit-to lead and lead optimization

The discovery, synthesis and SAR of a novel series of 3-benzyl-1,3-oxazolidin-2-ones as positive allosteric modulators (PAMs) of mGluR2 is described. Expedient hit-to-lead work on a single HTS hit led to the identification of a ligand-efficient and structurally attractive series of mGluR2 PAMs. Human microsomal clearance and suboptimal physicochemical properties of the initial lead were improved to give potent, metabolically stable and orally available mGluR2 PAMs.

Inhibitors of alprazolam metabolism in vitro: effect of serotonin‐ reuptake‐inhibitor antidepressants, ketoconazole and quinidine.

1. The biotransformation of the triazolobenzodiazepine alprazolam (ALP) to its hydroxylated metabolites (4-OH-ALP and alpha-OH-ALP) was evaluated in human, monkey, rat, and mouse liver microsomes. 2. In all species 4-OH-ALP was the principal metabolite, accounting for 84% of clearance in human microsomes compared with 16% for alpha-OH-ALP. 3. Among the serotonin-specific reuptake inhibitors fluoxetine (FLU) and sertraline (SERT), and their respective demethylated metabolites norfluoxetine (NOR) and desmethylsertraline (DES), NOR was the most potent inhibitor (mean Ki for 4-OH-ALP formation in humans: 11 microM), FLU the weakest (Ki = 83 microM), with SERT and DES falling in between (Ki = 24 and 20 microM). 4. The in vitro data predict 29% inhibition of ALP clearance at mean FLU and NOR plasma concentrations of 77 ng ml-1 and 72 ng ml-1, respectively, after correction for liver:water partition ratios in the range of 12-14. The observed mean degree of inhibition in a previous in vivo study was 21%. 5. Ketoconazole was a potent inhibitor of ALP metabolism in vitro (Ki = 0.046 microM), suggesting that ALP hydroxylation is mediated by the cytochrome P450-3A sub-family. Quinidine was a weak inhibitor (Ki = 626 microM).