Analytical method development and validation for the simultaneous estimation of lopinavir and ritonavir by RP-HPLC method in tablet dosage form

Lopinavir and ritonavir are protease inhibitor category of antiretroviral drugs. Both are used for the treatment of HIV/AIDS and COVID. A rapid and precise reverse phase high performance liquid chromatographic method has been developed for the validation of lopinavir and ritonavir in its bulk form as well as in tablet dosage form. Chromatography was carried out on a waters reliant C8, 250 x 4.6 mm, 5 & mu; column using a mixture of monobasic potassium phosphate buffer, and acetonitrile in proportion 55:45 v/v as the mobile phase at a flow rate of 1.5 ml/min. The detection was carried out at 215 nm. The retention time of the lopinavir and ritonavir was found to be 30.887 and 24.087 min, respectively. The method produces linear responses in the concentration range of 12.5-37.5 & mu;g/ ml and 3.125-9.375 & mu;g/ml, respectively, for lopinavir and ritonavir. The method precision for the determination of assay was below 2.0% RSD. The method is useful in the quality control of bulk and pharmaceutical formulations. The optimized method was validated and proved to be suitable for the quality control of the mentioned drugs in the tablet pharmaceutical dosage form, according to ICH guidelines. The developed method was found to be fairly precise, rapid and economical for simultaneous estimation of lopinavir and ritonavir when compared with the reported method.