A-192621 is a potent, nonpeptide, orally active and selective endothelin B (ETB) receptor antagonist with an IC50 of 4.5 nM and a Ki of 8.8 nM. The selectivity of A-192621 is 636-fold higher than ETA (IC50 of 4280 nM and Ki of 5600 nM). A-192621 promotes apoptosis in PASMCs. A-192621 alos causes elevation of arterial blood pressure and an elevation in the plasma ET-1 level.

IRL 2500 is a potent Endothelin receptor antagonist. IRL 2500 shows IC50 values of 1.3 and 94 nM for ETB and ETA receptors, respectively. IRL 2500 inhibits ETB receptor-mediated blood pressure increase and renal vascular resistance in rats in vivo.

Bosentan is an endothelin (ET) receptors antagonist for ET-A and ET-B with Ki of 4.7 nM and 95 nM, respectively.

Bosentan is a competitive and dual antagonist of endothelin-1 at the endothelin-A (ET-A) and endothelin-B (ET-B) receptors.

Avosentan(Ro 67-0565; SPP-301) is a potent, selective endothelin receptor(ETA receptor) antagonist.