Androstane impurities are unwanted substances that can be found in pharmaceuticals, specifically in androstane-based drugs. These impurities can arise during the manufacturing process or from degradation over time. They can potentially affect the efficacy and safety of the drug, making it important to identify and control them. Analytical techniques such as chromatography and spectroscopy are used to detect and quantify these impurities in order to ensure the quality and purity of the drug product.