Apixaban Impurity A Catalogue A186731 CAS 545445-44-1 M.W 355.43 M.F C20H25N3O3 Specifications FAQs 3-Morpholin-4-yl-1-[4-(2-oxopiperidin-1-yl)phenyl]-5,6-dihydro-1H-pyridin-2-one