1H-1-ethyl Candesartan Cilexetil, which is a process-related impurity commonly found in the bulk synthesis of candesartan cilexetil, is a potent, long-acting, and selective angiotensin II type 1 receptor (AT1) antagonist.

Angiotensin II is a peptide that is mainly generated by the angiotensin converting enzyme and chymase, which plays a vital role in regulating blood pressure and sodium homeostasis via specific receptors including AT1[1]. AT1, localized in the kidney, heart, brain, adrenal gland, adipocytes, vascular smooth muscle cells, platelets, and placenta, is a major component of the renin-angiotensin system. Furthermore, AT1 mediates the classical biological actions of angiotensin II. Also, AT1 has seven helical transmembrane domains, which is the characteristic of the superfamily of G-protein-coupled receptors. Carboxyl-terminal region structure of AT1 plays important roles in receptor internalization, desensitization and phosphorylation [2].

In vitro: Up to now, in vitro study of 1H-1-ethyl candesartan cilexetil is still in the development stage.

In vivo: Up to now, in vivo study of 1H-1-ethyl candesartan cilexetil is still in the development stage.

References:
[1].  Otsuka, M. Reduction of bleomycin induced lung fibrosis by candesartan cilexetil, an angiotensin II type 1 receptor antagonist. Thorax. 2004; 59(1): 31-38.
[2].  GUO, D., SUN, Y., HAMET, P., & INAGAMI, T. The angiotensin II type 1 receptor and receptor-associated proteins. Cell Research. 2001; 11(3): 165-180.