CAS 57-87-4 appears in our catalog under these names: Ergocalciferol EP Impurity B (Ergosterol), Ergosterol, >95% (HPLC), Ergosterol, Ergosterol (Provitamin D2), Ergosterol/ 99.8% (existing batch purity). Offered by: Chemat Brand, TRC, Mikromol, Dr. Ehrenstorfer, GLPBio. Available pack sizes: on request, 100mg, 10mg, 1g, 25mg, 10mM (in 1ml dmso), 5g, 25g.