Cilastatin is a medication used in combination with antibiotics to treat serious infections. Impurities can occur during the manufacturing process, and may impact the safety, efficacy, and quality of the drug. The identification and quantification of Cilastatin impurities is essential to ensure the drug product meets regulatory requirements and is safe for patient use. Various analytical methods are used to detect and measure these impurities, including high-performance liquid chromatography (HPLC) and mass spectrometry (MS).