Identification and determination of selected angiotensin II receptor antagonist group drugs by HPLC method

Losartan potassium, valsartan, telmisartan, irbesartan, eprosartan mesylate and candesartan cilexitil, the angiotensin II receptor antagonists, were analyzed in bulk substances and in tablets: Lorista tablets 50 mg, Diovan tablets 160 mg, Micardis tablets 20 mg, Aprovel tablets 300 mg, Teveten tablets 600 mg and Blopress tablets 16 mg. The conditions for identification by HPLC method in a gradient system and for determination of those compounds in isocratic systems were developed. The determination was carried out using Zorbax SB-Phenyl column with UV-VIS detector set at 230 nm and the following mobile phases: 0.1 mol/L sodium acetate (pH = 5.5) - acetonitrile - methanol in 35:9:6 v/v/v ratio for eprosartan mesylate and valsartan, in 15:6:4 v/v/v ratio for losartan potassium and irbesartan and in 10:9:6 v/v/v ratio for telmisartan and candesartan cilexitil. The recovery from simulated tablets was determined and amounted to: for eprosartan mesylate - 99.04%, valsartan - 100.0%, losartan potassium - 100.03%, irbesartan - 100.35%, telmisartan - 100.06% and candesartan cilexitil - 100.40%.