Identification of aryl sulfonamides as novel and potent inhibitors of Na1.5.

We describe the synthesis and biological evaluation of a series of novel aryl sulfonamides that exhibit potent inhibition of Na1.5. Unlike local anesthetics that are currently used for treatment of Long QT Syndrome 3 (LQT-3), the most potent compound (-)-6 in this series shows high selectivity over hERG and other cardiac ion channels and has a low brain to plasma ratio to minimize CNS side effects. Compound (-)-6 is also effective inshortening prolonged action potential durations (APDs) in a pharmacological model of LQT-3 syndrome in pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Unlike most aryl sulfonamide Na inhibitors that bind to the channel voltage sensors, these Na1.5 inhibitors bind to the local anesthetic binding site in the central pore of the channel.