Figure 5: HPLC chromatogram of Hypersil BDS C-18 (25cm) Column and mobile phase consisted of (A) acetonitrile and (B) buffer pH=3.5 in ratio 35:65%where a- ammonium acetate 0.02M b- citrate buffer 0.02M for trials to separate Losartan potassium(LOS), Irbesartan (IRB), Valsartan (VAL) and Telmisartan (TELM) respectively.