Flumazenil is a benzodiazepine antagonist that is used to reverse the effects of sedative medications. Flumazenil impurities refer to any substances that are present in a sample of flumazenil that are not the active ingredient. These impurities are typically unwanted and can affect the purity and potency of the drug. It is important to accurately identify and quantify these impurities to ensure the safety and efficacy of the medication.