Characterization and quantitative determination of impurities in piperaquine phosphate by HPLC and LC/MS/MS

Four impurities in piperaquine phosphate bulk drug substance were detected by a newly developed gradient reverse phase high performance liquid chromatographic (HPLC) method. These impurities were identified by LC/MS/MS. The structures of impurities were confirmed by spectroscopic studies (NMR and IR) conducted using synthesized authentic compounds. The synthesized reference samples of the impurity compounds were used for the quantitative HPLC determination. The system suitability of HPLC analysis established the validity of the separation. The method was validated according to ICH guidelines with respect to specificity, precision, accuracy and linearity. Forced degradation studies were also performed for piperaquine phosphate bulk drug samples to demonstrate the stability indicating power of the newly developed HPLC method.