Azilsartan Medoxomil Potassium (TAK-491 Potassium) is an orally administered angiotensin II receptor type 1 antagonist with IC50 of 0.62 nM, which used in the treatment of adults with essential hypertension.

Azilsartan Medoxomil Potassium is a prodrug, which is rapidly converted to the active moiety, azilsartan (TAK-536), by ester hydrolysis in the gut and plasma during absorption after oral administration. Azilsartan selectively blocks the binding of angiotensin II to the AT1 (angiotensin II type 1) receptors found in the vascular smooth muscle and the adrenal gland, thereby promoting vasodilation and a decrease in the effects of aldosterone. Azilsartan is a highly selective antagonist to the AT1 receptor, with an IC50 of 2.6 nM, exhibiting a >10,000-fold affinity for the AT1 receptor compared with the AT2 receptor, and has not shown affinity for other cardiac receptors or ion channels[1]. The inhibitory effect of Azilsartan persists after washout of the free compound (IC50 value of 7.4 nM). Azilsartan also inhibits the accumulation of angiotensin II -induced inositol 1-phosphate (IP1) in the cell-based assay with an IC50 value of 9.2 nM, and this effect is resistant to washout (IC50 value of 81.3 nM)[1].