Policresulen is a drug used to treat various medical conditions. During its manufacturing process, impurities can be introduced that may affect its efficacy or safety. These impurities are typically unwanted substances that are present in small quantities but can still have negative effects. Therefore, it is important to monitor and control the levels of these impurities to ensure the quality and safety of the final product. Analytical methods such as HPLC and GC are used to detect and quantify these impurities.