Used primarily as a reference standard in pharmaceutical quality control and analytical testing during the synthesis and purification of afatinib, a tyrosine kinase inhibitor. It helps in identifying and quantifying impurities in afatinib drug substances and formulations, ensuring product purity and regulatory compliance. Also utilized in stability studies to monitor degradation pathways and assess the shelf life of afatinib-based medications. Its presence and behavior are critical in validating analytical methods such as HPLC and LC-MS for accurate detection of related substances in active pharmaceutical ingredients.