Potent KV1.3 channel blocker (EC50 = 3 nM). Preferentially binds the C-type inactivated state of the channel, similar to the activity of CP 339818 (Cat. No. 1399). Displays 17- to 70-fold selectivity over closely-related KV1 channels (KV1, KV2, KV4 and KV7); exhibits activity at KV1.5 (IC50 = 7.7 nM). Suppresses proliferation of human and rat myelin-specific effector memory T cells (EC50 values are 25 and 60 nM respectively). Purity 99%. MW (observed): 334.37