Cetrorelix is a synthetic peptide used in the treatment of prostate cancer and endometriosis. To ensure the safety and efficacy of the drug, it is important to identify and quantify any impurities present. These impurities may include related peptides, degradation products, or residual solvents. Analytical methods such as HPLC and mass spectrometry are used to detect and characterize cetrorelix impurities, allowing for proper quality control and monitoring throughout the manufacturing process.