Ibrutinib Impurity LDBX is a specified impurity or degradation product associated with Ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor used in treating B-cell malignancies such as mantle cell lymphoma, chronic lymphocytic leukemia, and Waldenström's macroglobulinemia. This reference standard is employed in pharmaceutical quality control, analytical method development, and stability testing to detect and quantify impurities, ensuring the safety, purity, and efficacy of Ibrutinib drug substances and formulations.