Iloprost impurities are the byproducts or contaminants that may be present in Iloprost drug substances or drug products. These impurities may arise due to various factors such as manufacturing processes, storage conditions, or degradation of the drug. The presence of these impurities in Iloprost can affect the quality, safety, and efficacy of the drug, and hence, it is essential to monitor and control their levels during the drug development and manufacturing process. Analytical techniques such as chromatography and spectroscopy are commonly used to identify and quantify these impurities.