WAY-100635 maleate salt is a potent, selective and high affinity SR-2B antagonist with a pIC50 of 10.4. The affinity (pKi) of WAY-100635 maleate salt for tSR-2B is 9.5. In addition, WAY-100635 maleate salt also blocks serotonin-evoked contraction of rat isolated stomach fundus.