Budesonide EP Impurity B Catalogue B501462 CAS 1040085-98-0 M.W 402.49 M.F C23H30O6 Specifications FAQs Synonyms:16a,17-[(1RS)-ethylidenebis(oxy)]-11ß,21-dihydroxypregna-1,4-diene-3,20-dione