Discovery and biological evaluation of potent, selective, orally bioavailable, pyrazine-based blockers of the Na(v)1.8 sodium channel with efficacy in a model of neuropathic pain.

Journal: Bioorganic & Medicinal Chemistry
Published:
Abstract

Na(v)1.8 (also known as PN3) is a tetrodotoxin-resistant (TTx-r) voltage-gated sodium channel (VGSC) that is highly expressed on small diameter sensory neurons. It has been implicated in the pathophysiology of inflammatory and neuropathic pain, and we envisioned that selective blockade of Na(v)1.8 would be analgesic, while reducing adverse events typically associated with non-selective VGSC blocking therapeutic agents. Herein, we describe the preparation and characterization of a series of 6-aryl-2-pyrazinecarboxamides, which are potent blockers of the human Na(v)1.8 channel and also block TTx-r sodium currents in rat dorsal root ganglia (DRG) neurons. Selected derivatives display selectivity versus human Na(v)1.2. We further demonstrate that an example from this series is orally bioavailable and produces antinociceptive activity in vivo in a rodent model of neuropathic pain following oral administration.

Authors
Marc J Scanio, Lei Shi, Irene Drizin, Robert Gregg, Robert Atkinson, James Thomas, Matthew Johnson, Mark Chapman, Dong Liu, Michael Krambis, Yi Liu, Char-chang Shieh, Xufeng Zhang, Gricelda Simler, Shailen Joshi, Prisca Honore, Kennan Marsh, Alison Knox, Stephen Werness, Brett Antonio, Douglas Krafte, Michael Jarvis, Connie Faltynek, Brian Marron, Michael Kort
Relevant Conditions

Neuralgia