Selective NaV1.7 channel blocker. Preferentially inhibits neuronal NaV1.7, 1.2 and 1.3 (IC50 values are 26, 150 and 338 nM respectively), compared to muscle subtypes NaV1.4 and 1.5 (IC50 = >10 μM). Inhibits the channel by binding at the neurotoxin receptor site 4 in the S3-S4 linker of domain II, trapping the voltage sensor in the inward, closed configuration. MW (observed): 4106.79.