A digitized impurity database analysis method for determining the impurity profiles of gatifloxacin in bulk materials and injections

HPLC has become the most important analytical technique for impurity profiling in order to assure the quality of pharmaceutical products. Although HPLC is considered as a well-established technology, it requires CRS (chemical reference substances) of impurities for qualification and quantification of impurity peaks. Many impurity CRS have been widely used for the impurity profile control, which causes a high cost of production in practice. In this study, we developed a new method for impurity profiling control, so called digitized impurity database analysis, which does not directly use impurity CRS. Using a quinolone antibiotic, gatifloxacin as an example, we first analyzed its impurities by DAD (diode array detector) to compile a digitized impurity database and then used the database to analyze the impurities in the samples of domestic gatifloxacin bulk materials and injections in China. We identified the impurities in the chromatogram by combining two-dimensional chromatographic spectral correlation analyses of ultraviolet spectra data and relative retention times. The content of the impurities was determined using relative response factors of impurity to gatifloxacin as normalization factors. The digital impurity database analysis technology we developed is a “green”, economic and convenient method that may eliminate the use of impurity CRS in the impurity profile control.