separation of hydrocortisone acetate n cortisone acetate

[fae]

hi,
i'm using bp method for hydrocortisone acetate related substances which required me to achieve resolution at least 4.2 between hydrocortisone acetate n cortisone acetate peak. the mobile phase used r 40% ACN, C18,250x4.6mm,5micron, 1ml/min,254nm. i'm facing a problem to separate those two drugs...can sumone suggest what kind of column r suitable to separate both drugs?? :

[tom jupille]

Since you are running a compendial method, your best bet would be to find the original monograph to determine the column that they used in the first place. If you cannot get that exact column, then you can search the PQRO database on the USP website (http://www.usp.org/USPNF/columnsDB.html) to find the closest equivalent.