Overall Review on Development and Validation of RP-HPLC Method for Relugolix in Bulk and Marketed Formulations

Relugolix is a modern, orally active, non-peptide gonadotropin-releasing hormone (GnRH) receptor antagonist widely used in the treatment of hormone-dependent disorders such as advanced prostate cancer, uterine fibroids, and endometriosis. Chromatographic separation was achieved using an Inertsil ODS-2 C18 column (4.6 × 150 mm, 5 µm) with a mobile phase composed of Acetonitrile and 0.1% Orthophosphoric Acid buffer in the ratio of 60:40 v/v, delivered at a flow rate of 1.0 mL/min. Detection was carried out at 293 nm using a PDA detector. The developed method produced a sharp, symmetric peak at a retention time of approximately 2.0 minutes, indicating excellent resolution and reduced analysis time. The method exhibited remarkable linearity over the concentration range of 20–100 µg/mL, with a correlation coefficient (R²) of 0.999. The LOD and LOQ were 0.05 µg/mL and 0.17 µg/mL, respectively, demonstrating high sensitivity. Accuracy studies indicated percentage recoveries within 98–102%, while precision results confirmed excellent repeatability with %RSD values below 2%. The method was found to be specific, robust, and free from excipient interference. The assay of a marketed formulation yielded 99.12% of the labelled claim[1].