A potent, reversible, selective, CFTR chloride channel blocker. Inhibits CFTR short-circuit current in < 2 minutes in a voltage-independent manner (Ki = ~ 300 nM). At concentrations fully inhibiting CFTR, CFTR(inh)-172 does not block increase of cellular cAMP or inhibit non-CFTR Cl(-) channels, multidrug resistance protein-1 (MDR-1), ATP-sensitive K(+) channels, or a series of other transporters. MW: 409.4. Purity ≥98% by HPLC