Figure 2: HPLC chromatogram of Amlodipine besylate (2.33 min), Losartan potassium (2.92 min), Valsartan (3.68 min) and Atorvastatin calcium ( 6.36 min) respectively on spherical monomeric C18 Column and mobile phase consisted of (A) acetonitrile and (B) acetate buffer pH=3.5 in ratio 55:45% at flow rate=1.5 ml/min by an isocratic technique.