Imatinib Impurity E is a specific impurity found in Imatinib, an orally available inhibitor of multiple tyrosine kinases, including BCR/ABL, v-Abl, PDGFR, and c-kit. Imatinib (STI571) operates by semi-competitively inhibiting enzyme activity; it binds adjacent to the ATP binding site, inducing a closed or self-inhibited conformation [1] [2] [3] [4]. Additionally, Imatinib acts as an inhibitor against SARS-CoV and MERS-CoV [5].