Migalastat impurities are chemical compounds that are present in small amounts in the drug substance of migalastat, which is used to treat Fabry disease. These impurities are formed during the manufacturing process and can affect the quality and safety of the drug. Therefore, it is important to monitor and control their levels to ensure the efficacy and safety of migalastat. Different analytical techniques are used to identify and quantify these impurities, and strict regulatory guidelines are in place to ensure their control.