IDENTIFICATION AND CHARACTERIZATION OF IMPURITIES IN SULPHACETAMIDE INJECTABLE FORMULATION BY STABILITY-INDICATING UPLC-ESI-MS/MS METHOD FOLLOWING ICH GUIDELINES

Sulphacetamide is a sulfonamide antimicrobial widely used in injectable formulations for ocular and systemic bacterial infections. However, its chemical sensitivity to environmental factors poses a significant challenge for formulation stability, requiring a comprehensive impurity profiling approach. The current study aimed to develop and validate a stability-indicating UPLC-ESI-MS/MS method for the identification and characterization of impurities and degradation products of Sulphacetamide under various stress conditions in accordance with ICH Q1A (R2) guidelines. Forced degradation studies were performed by subjecting Sulphacetamide to acidic, basic, oxidative, thermal, and photolytic stress. Chromatographic separation was achieved using a BEH C18 column with an optimized mobile phase under gradient elution. Mass spectral data were acquired using electrosprayionization in positive mode, enabling structural elucidation of degradation products based on fragmentation patterns and m/z values. The method showed excellent specificity, sensitivity, and resolution for Sulphacetamide and its impurities. Major degradation was observed under acidic and oxidative conditions, yielding characteristic fragments such as m/z 131.38, 149.54, 200.02, 325.42, and 425.72. Minor degradation was noted under basic conditions, while samples subjected to thermal and photolytic stress showed negligible changes. The developed UPLC-MS/MS method is robust, accurate, and stability-indicating, making it suitable for routine quality control and regulatory submissions. The comprehensive impurity profile enhances understanding of Sulphacetamide degradation pathways, ensuring product safety and compliance with ICH Q3B (R2) guidelines.