Daclatasvir Impurity B is primarily used in the pharmaceutical industry as a reference standard during the quality control and analytical testing processes of Daclatasvir, an antiviral medication. It helps in identifying, quantifying, and monitoring the presence of this impurity in drug formulations to ensure the safety, efficacy, and compliance of the final product with regulatory standards. Additionally, it aids in the development and validation of analytical methods, contributing to the overall quality assurance of the drug manufacturing process.