Author: D. Nani Prasad Tentu Nageswara Rao and T. B. Patrudu

DOI: http://doi.org/10.31788/RJC.2026.1939777

A novel reverse-phase high-performance liquid chromatography (RP-HPLC) approach was created and validatedfor the quantification of impurities in 200 mg film-coated tablets of Fidaxomicin. This method effectively distinguishesFidaxomicin from its degradation products. The validation was executed in accordance with the International Council for Harmonization (ICH) guidelines, which included parameters such as specificity, precision, linearity, accuracy, limit of detection (LOD), limit of quantification (LOQ), and robustness. Five impurities associatedwithdegradation were identified and characterized using the appropriate impurity standards. Chromatographic separationwas achieved on an X Bridge C18 column (250 × 4.6 mm, 5 µm), utilizing a mobile phase systemthat consistedof mobile phase A (phosphate buffer, pH 7, and methanol in an 80:20 ratio) and mobile phase B (100%acetonitrile). The flow rate was established at 1.0 mL/min, with an injection volume of 10 µL, a run time of 50 minutes, anddetection conducted at a wavelength of 237 nm. The structures of the five degradation impurities were elucidatedthrough LC-MS analysis. In conclusion, the RP-HPLC method developed is robust, specific, stability-indicating, andsuitable for routine quality control and stability evaluation of Fidaxomicin film-coated tablet formulations.

Keywords: Fidaxomicin tablet, Accuracy, Linearity, Method Validation, and Reverse Phase HPLC.