DEVELOPMENT AND VALIDATION OF STABILITY INDICATING HPLC METHOD FOR THE DETERMINATION OF LAPATINIB IMPURITIES IN BULK AND FINISHED FORMULATIONS

A simple, sensitive and stability indicating reverse phase high performance liquid chromatography method (RP-HPLC) was developed and validated for the estimation of Lapatinib and its related substances in bulk and finished dosage forms. The newly developed method was assessed using Zorbax Eclipse C18 (3.5 µm, 100 × 4.6 mm) HPLC column with pH- 4.5 ammonium formate buffer and acetonitrile as mobile phase in gradient elution mode with a run time of 35 minutes. UV detection was carried out at a wavelength of 261 nm with an injection volume of 5 µL. The developed method was validated as per the ICH guidelines with respect to precision, accuracy, linearity, robustness, specificity and system suitability. Lapatinib samples were exposed to thermal, photolytic, acidic, basic and oxidative stress conditions. The stressed samples were analyzed by the developed method to establish the stability indicating power of the method. The LOD values were 0.009, 0.012 and 0.011 µg/ml and the LOQ values were 0.027, 0.035 and 0.0304 µg/ml respectively for impurity-1, impurity-2 and impurity-3 of Lapatinib. The average recovery values of Lapatinib related substances were found to be in the range of 97.5-101.2 %. The developed method was linear over a range of 0.027- 1.5 µg/ml for Lapatinib impurities. The proposed method was found to be suitable and accurate for the determination of Lapatinib related substances in bulk and finished formulations.