Abstract :An Accurate, Precise, Rugged, Reproducible Reverse Phase High Pressure Liquid Chromatographic
(RP-HPLC) method has been developed and validated for the simultaneous estimation of
Lopinavir and Ritonavir in pharmaceutical dosage form of anti-retroviral protease inhibitor class of
compounds. The method was achieved by using the mixed organic mobile phases of Acetonitrile:
Methanol with the buffer of potassium dihydrogen phosphate (pH 3.5) and Xbridge C18 (250 mm ×
4.6 mm i.d., 3.5 µm. The flow rate was set as 1.1 ml/min has provided a good peak shape of Ritonavir
and Lopinavir were found well separated at 5.7 and 6.6 min respectively