DEVELOPMENT AND VALIDATION OF A FORCED DEGRADATION UPLC METHOD FOR THE SIMULTANEOUS DETERMINATION OF EPLERENONE AND TORSEMIDE IN BULK AND PHARMACEUTICAL DOSAGE FORM

Aim: To develop and validate a rapid, sensitive, and stability-indicating Ultra Performance Liquid Chromatographic (UPLC) method for simultaneous estimation of Torsemide (TOR) and Eplerenone (EPL) in combined pharmaceutical dosage forms. Methods: Chromatographic separation was performed on a Waters ACQUITY UPLC system with a C-18 BEH column (1.7 µm, 2.1 x 50 mm) using an isocratic mobile phase of Phosphate Buffer (pH 4.0) and Acetonitrile in a ratio of 40:60 (v/v) at a flow rate of 0.8 ml/min. Detection was performed at 230 nm. The method was validated in accordance with the recommendations outlined in ICH Q2(R1) for specificity, linearity, accuracy, precision, robustness, limit of detection (LOD), limit of quantification (LOQ), and forced degradation studies. Results:The retention times of Torsemide and Eplerenone were 1.267 and 2.133 minutes, respectively, with a total run time of 4 minutes. The developed method showed remarkable linearity for the range 2-16 µg/ml for Torsemide (r² = 0.9999) and 5-40 µg/ml for Eplerenone (r² = 0.9998). Recovery percentages validated the accuracy, with rates ranging from 99.30% to 99.84%. The method validation parameters, such as precision (%RSD < 0.21) and robustness, also established that the method is reliable. Under basic and oxidative forced degradation conditions, 25.2% (for TOR) and 57.7% (for EPL) and 22.5% (for TOR) and 83.6% (for EPL) degradations were observed, respectively. At the same time, the two drugs remained stable under acidic, photolytic, and thermal stress. Conclusion: The UPLC method developed was found to be accurate, precise, robust, and stability-indicating. The technique can be employed for routine QC and stability studies of these drugs, in bulk and combined dosage forms.