Method development and validation of ritonavir and lopinavir in bulk and dosage form by RP-HPLC

A reversed phase high-performance liquid chromatography method was developed and validated for the quantitative determination of two antiviral drugs ritonavir and lopinavir. Chromatography was carried out on a reversed phase zorbxs, C18column,of( 250x4.6mm,5?) with mobile phase mixture of buffer and solvent(40:60). Acetonitrile and methanol was used as mobile phase solvent (80:20) and the pH was adjusted to 3 with O- phosphoric acid, at a flow rate 1ml/min .The retention time for ritonavir is 2.2min and lopinavir is 3.68min. The UV range was detected at 240nm for lopinavir and ritonavir respectively. The different analytical performance parameters such as linearity, precision, accuracy, and specificity, limit of detection (LOD) and limit of quantification (LOQ) were determined according to International Conference on Harmonization ICH Q2B guidelines. The linearity of the calibration curves for each analyte in the desired concentration range is good (r2>0.9). Limits for repeatability and intermediate prescision individual assay must be within 98% to102%. Hence the proposed method is highly sensitive, precise and is successfully applied for the reliable quantification of API content in the commercial formulations of lopinavir and ritonavir.