A Simple Reversed Phase High Performance Liquid Chromatography Method for the Estimation of Related Substances, Assay of Cabozantinib and Nivolumab and its Application to Dissolution Studies

The present work describes the development and subsequent validation of a novel, simple, selective and stability indicating gradient reversed phase high performance liquid chromatography method for the quantitative determination of related substances, assay of cabozantinib and nivolumab and its application to dissolution studies. The chromatographic method was optimized using the impurity-spiked solution. A good resolution between the peaks was achieved under selected chromatographic conditions. The separation was accomplished on an X-Bridge C18, 150×4.6 mm, 3.5 μ column connected to a photo diode array detector using 0.1 % orthophosphoric acid in water as mobile phase A and acetonitrile as mobile phase B, under gradient elution. The mobile phase flow rate was maintained at 1.0 ml/min. The detection of the constituents was done at 216 nm using a ultra-violet detector. Recovery studies were satisfactory and the correlation coefficient for two active pharmaceutical ingredients and their related substances, 0.999 indicates the linearity of the method within the limits. Limit of detection and limit of quantification for all impurities and cabozantinib and nivolumab were established with respect to the test concentration. Specificity, accuracy, precision, ruggedness and robustness were determined as part of the method validation. The performance of the method was validated according to the current International Council for Harmonisation requirements. Moreover, the dissolution study was performed on active pharmaceutical ingredients to estimate the recovery using the same method. Validation of the developed reversed phase high performance liquid chromatography procedure revealed that all the degradation products formed during stress conditions and related impurities were well separated from their active pharmaceutical ingredients and peaks were well resolved from each other with appropriate retention time. The method was characterized by good linearity, specificity, low values of limit of detection and quantisation, accuracy, precision, ruggedness and robustness. All statistical results were within the acceptance criteria and the proposed method is simple, fast, accurate, precise and reproducible hence, it can be applied for routine dissolution analysis and employed for quality control of drug samples during stability studies.