Pakistan Journal of Pharmaceutical Sciences

Abstract: This study developed and validated a High-Performance Liquid Chromatographic (HPLC) method for the determination of related substances in Morinidazole Sodium Chloride Injection. Background: As a novel nitroimidazole antimicrobial, the quality control of Morinidazole is crucial for ensuring clinical drug safety, particularly in monitoring specific impurities that may arise during production or storage. Objective: To establish a method capable of simultaneously quantifying two Morinidazole impurities, three Ornidazole impurities, and one Levornidazole impurity (Levornidazole impurity II), and to evaluate its environmental friendliness. Methods: Separation was performed using a Waters Symmetry C18 column with a mobile phase consisting of 0.05 mol/L potassium dihydrogen phosphate buffer (pH 7.0) and acetonitrile in a gradient elution program. The flow rate was 1.0 mL/min, the column temperature was maintained at 30°C, the detection wavelength was set at 319 nm, and the injection volume was 20 µL. Impurity quantification was performed using the main component self-compare method (Quantitative Analysis of Multi-components by a Single Marker, QAMS), and the results were compared with those obtained by the external standard method. Method validation was conducted in accordance with ICH guidelines. Results: The method demonstrated good specificity. The limit of quantification (LOQ) and limit of detection (LOD) were 0.2 µg/mL and 0.06 µg/mL, respectively. Excellent linearity (r ? 0.995) was achieved within the range of 0.2–4.0 µg/mL. The average recoveries ranged from 95% to 105% (RSD < 2.0%). Both the system suitability solution and the test sample solution remained stable for 30 hours. The Analytical Greenness (AGREE) and Blue Applicability Grade Index (BAGI) scores for the QAMS method were 0.66 and 80.0, respectively. No significant difference was found between the results obtained by the QAMS method and the external standard method. Conclusion: The established HPLC-QAMS method is accurate, sensitive, and environmentally friendly. It is suitable for the quality control of related impurities in Morinidazole Sodium Chloride Injection and provides technical support for the clinical safety evaluation of this preparation.