Eplerenone-13C,d3 (Epoxymexrenone-13C,d3) is 13C labeled Eplerenone. Eplerenone (Epoxymexrenone) is a selective, highly specific and orally active aldosterone blocker (SAB). Eplerenone also is a selective mineralocorticoid receptor antagonist (MRA) with IC50 value of 0.081 µM. Eplerenone can be used for the research of hypertension, atherosclerosis, chronic systolic heart failure (HF) and cardiovascular (CV)[1][2].