ICA 121431 is a voltage-gated sodium channel (Nav) blocker that selectively blocks Nav1.1 and Nav1.3 over Nav1.4, and Nav1.5-1.8 channels (IC50s = <20, 19, 240, and >10,000 nM, respectively). It induces a concentration-dependent hyperpolarizing shift in voltage dependence of inactivation of Nav1.3 channels at a concentration 1 μM but has no effect on resting channels. Substitution of the Nav1.3 domain IV voltage-sensor domain (VSD4) with the Nav1.5 VSD4 reduces ICA 121431 potency by approximately 500-fold.
![2,2-Diphenyl-N-[4-(thiazol-2-ylsulfamoyl)-phenyl]-acetamide](https://www.chemicalbook.com/CAS/20150408/GIF/313254-51-2.gif)
