Potent and selective inhibitor of human NaV1.3 and NaV1.1 channels (IC50 values are 13 and 23 nM respectively). Exhibits up to 1,000 fold selectivity against other TTX-sensitive or resistant sodium channels (IC50 values are >10 μM for human NaV1.5 and NaV1.8 channels). Interacts with an inhibitory interaction site distinct from those bound by TTX and local anesthetic-like modulators. Purity 98%. MW (observed): 449.55