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.