Displaying 21 results of Macitentan Impurities Macitentan is a medication used to treat pulmonary arterial hypertension. During the manufacturing process of macitentan, certain impurities may be present which can affect the quality and efficacy of the medication. These impurities need to be identified and controlled to ensure the safety and effectiveness of the final product. Regulatory bodies such as the US FDA have set limits and guidelines for the identification and control of these impurities in macitentan.