Tasimelteon is a synthetic melatonin receptor agonist used to treat sleep disorders. Tasimelteon impurities refer to any other substances that may be present in the drug product that are not the active ingredient. These impurities may arise during the manufacturing process or storage of the drug and can affect the potency, purity, and safety of the drug. Therefore, it is important to identify and control these impurities to ensure the quality of Tasimelteon.