Teriflunomide is a pharmaceutical drug commonly used for the treatment of multiple sclerosis. However, the drug may contain impurities that can affect its purity, potency, and safety. These impurities may originate from the manufacturing process or degradation of the drug product. It is important to monitor and control the levels of these impurities to ensure the quality and efficacy of the drug. Analytical methods such as HPLC, GC, and LC-MS are used to detect and quantify these impurities.