Ibrutinib Impurity BX is a reference standard impurity of the pharmaceutical drug Ibrutinib (a Bruton's tyrosine kinase inhibitor). It is used in analytical chemistry for the identification, qualification, and quantification of impurities in Ibrutinib drug substances and formulations during pharmaceutical quality control, stability testing, and regulatory compliance (e.g., ICH guidelines). This specialty chemical aids in ensuring the purity and safety of Ibrutinib-based medications for treating B-cell malignancies.