Figure 7: HPLC chromatogram of Hypersil BDS C-18 (25cm) Column and mobile phase consisted of (A) acetonitrile and (B) phosphate buffer in ratio 35:65% where a- pH=2.5 b- pH=4.5 c- pH=6.0 for trials to Losartan potassium(LOS), Irbesartan (IRB), Valsartan (VAL) and Telmisartan (TELM) respectively.