Macitentan is an orally active, dual endothelin receptor antagonist with tissue targeting properties. Macitentan inhibits both ETA and ETB receptors and prevents them from binding to ET-1. Macitentan displays high affinity and sustained occupancy of the ET receptors in human pulmonary arterial smooth muscle cells. One of the metabolites of macitentan is also pharmacologically active at the ET receptors and is estimated to be about 20% as potent as the parent drug in vitro. Macitentan is approved in the EU (as monotherapy or combination therapy) for the long-term treatment of pulmonary arterial hypertension (PAH) in adults of WHO functional class II or III, and in the USA for the treatment of PAH (WHO group I) to delay disease progression and reduce hospitalization for PAH.

Edonentan (BMS 207940) is a highly selective biphenylsulfonamide endothelin A receptor antagonist. (11)C- and (18)F-labeled analogs of edonentan were evaluated of novel PET radioligands for imaging the endothelin-A receptor. Edonentan was in clinical trials for the treatment of heart failure however its development has been discontinued.

BQ-123 is a selective endothelin receptor-1 antagonist; it is used as a biochemical tool in the study of endothelin receptor function. BQ-123 was suspected to contribute to the regulation of vascular tone humans. However, a study involving young normotensive subjects did not demonstrate any major role for BQ-123 regulation of vascular tone.

Edonentan (BMS 207940) is a highly selective biphenylsulfonamide endothelin A receptor antagonist. (11)C- and (18)F-labeled analogs of edonentan were evaluated of novel PET radioligands for imaging the endothelin-A receptor. Edonentan was in clinical trials for the treatment of heart failure however its development has been discontinued.

BQ-123 is a selective endothelin receptor-1 antagonist; it is used as a biochemical tool in the study of endothelin receptor function. BQ-123 was suspected to contribute to the regulation of vascular tone humans. However, a study involving young normotensive subjects did not demonstrate any major role for BQ-123 regulation of vascular tone.