Remdesivir impurities refer to any substances that are present in remdesivir drug formulations but are not the active ingredient itself. These impurities can be naturally occurring or can be introduced during the drug manufacturing process. It is important to control and monitor the levels of these impurities as they can affect the safety and efficacy of the drug. Analytical techniques such as high-performance liquid chromatography (HPLC) are used to detect and quantify these impurities. The presence of impurities can also affect the stability and shelf life of the drug, making their control essential for quality assurance.