Forced Degradation Studies, Method Development and Validation Of RP-HPLC Method for The Analysis of Endoxifen Citrate in Bulk and Tablet Dosage Form

Novelty: A new, stability-indicating RP-HPLC method was developed for the first time for Endoxifen citrate estimation in bulk and tablet formulations, including comprehensive forced degradation studies. Objective: To develop and validate a simple, accurate, and precise RP-HPLC method for quantification and stability assessment of Endoxifen citrate. Method: Chromatographic separation was achieved on a Phenomenex C18 column (250 × 4.6 mm, 5 µm) using methanol, acetonitrile, and water (60:30:10 v/v/v, 0.1% TEA) at 1.0 mL/min, with detection at 243 nm. Validation followed ICH Q2(R1) guidelines, and forced degradation was carried out under acidic, alkaline, oxidative, reduction, and thermal conditions. Results: The retention time was 4.3 min, linearity was 16–80 µg/mL (r² = 0.9998), recoveries were 99.62–100.16%, and %RSD <1.5%. Significant degradation occurred under acidic stress, confirming stability indication. Conclusion: The proposed RP-HPLC method is simple, accurate, precise, and stability-indicating, ideal for quality control and stability studies of Endoxifen citrate.