Discovery and biological evaluation of 5-aryl-2-furfuramides, potent and selective blockers of the Nav1.8 sodium channel with efficacy in models of neuropathic and inflammatory pain.

Nav1.8 (also known as PN3) is a tetrodotoxin-resistant (TTx-r) voltage-gated sodium channel (VGSC) that is highly expressed on small diameter sensory neurons and has been implicated in the pathophysiology of inflammatory and neuropathic pain. Recent studies using an Nav1.8 antisense oligonucleotide in an animal model of chronic pain indicated that selective blockade of Nav1.8 was analgesic and could provide effective analgesia with a reduction in the adverse events associated with nonselective VGSC blocking therapeutic agents. Herein, we describe the preparation and characterization of a series of 5-substituted 2-furfuramides, which are potent, voltage-dependent blockers (IC50 100-fold selectivity versus human sodium (Nav1.2, Nav1.5, Nav1.7) and human ether-a-go-go (hERG) channels. Following systemic administration,...