Abstract

A stability indicating LC method for lopinavir

Author(s): I.V.Soma Raju, P.Raghuram, J.Sriramulu

An isocratic reverse phase liquid chromatographic (RP-LC) assaymethod was developed for the quantitative determination of lopinavir in bulk drug and in pharmaceutical dosage form, used to treat antiviral. The developed method is also applicable for the related substances determination. The chromatographic separation was achieved on Agilent Zorbax SB- C18 250 4.6mm, 5m. The LC method employs solutionAas mobile phase. The solutionAcontains a mixture of phosphate buffer pH 4.0: acetonitrile (55:45, v/v). The flowrate was 1.5 mLmin-1and the detection wavelength was 210 nm. In the developed HPLC method the resolution between lopinavir and its potential impurities namely Imp-1, Imp-2, Imp-3 and Imp- 4was found to be greater than 10.0. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Considerable degradationwas found to occur in thermal,UV, acidmedium and oxidative stress conditions. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.7%. The developedRP-LCmethod was validated with respect to linearity, accuracy, precision and robustness.