Mequitazine is a sedative antihistamine used to treat allergic reactions such as hay fever, hives, and itching. Impurities in mequitazine can affect its efficacy and safety. These impurities can be the result of manufacturing processes, storage conditions, or other factors. The identification and control of mequitazine impurities are important to ensure the quality and safety of the drug product. Regulatory agencies have established limits for mequitazine impurities in drug products to ensure their safety and efficacy.