Budesonide Impurity 08 Catalogue B50148 CAS 93861-52-0 M.W 446.53 M.F C25H34O7 Specifications FAQs [6β,11β,16α(R)]-16,17-[Butylidenebis(oxy)]-6,11,21-trihydroxy-pregna-1,4-diene-3,20-dione