Tucatinib impurities are the by-products or unwanted substances that are present in Tucatinib drug substance. These impurities can be derived from the starting materials, synthetic process, or degradation of the drug substance. The presence of impurities in Tucatinib can affect the purity, potency, and safety of the drug product. Therefore, it is important to monitor and control these impurities during the development and manufacturing process of Tucatinib. Analytical methods are used to identify and quantify these impurities, and their levels must be below the acceptable limits set by regulatory authorities.