Olmesartan medoxomil is a potent and selective angiotensin AT1 receptor inhibitor with IC50 of 66.2 μM.Inhibition of Arachidonic acid (AA) metabolism by angiotensin II receptor blockers (ARBs) is detected in a concentration-dependent manner with IC50 of Olmesartan (66.2 μM). Olmesartan medoxomil (OLM) is a potent and selective angiotensin AT1 receptor blocker.The efficacy of Olmesartan (20 mg/kg) studied in db/db diabetic mice for a period of 12 weeks starting from week 10 to 12 of age. The db/db mice have 11.7 fold increased albuminuria in comparison to control mice at week 22 to 24 of age. Twelve weeks Olmesartan administration significantly reduces albuminuria in db/db mice by 77% as compared with placebo treated db/db mice. The albumin/creatinine ratio (ACR) is increased in db/db mice in comparison to control mice by 7.1 fold and Olmesartan treatment significantly decreases ACR by 59% in db/db mice.