High-pressure liquid chromatographic determination of corticosteroids in topical pharmaceuticals

Cortisone, hydrocortisone, prednisolone, and prednisone were separated on a reversed-phase microparticulate high-pressure liquid chromatographic (HPLC) column with a ternary mobile solvent containing tetrahydrofuran, methanol, and water. Cortisone acetate, hydrocortisone acetate, and prednisolone acetate were separated on the same reversed-phase column using acetonitrile-water. Various commercial topical formulations of these corticosteroids, except cortisone and prednisone, were prepared by both simple dilution and by extraction for analysis by the proposed HPLC procedure, by the blue tetrazolium procedure, and by the isoniazid procedure and/or phenylhydrazine method. Retention data are given for some common degradation products (C-17 ketones and C-17 carboxylic acid derivatives) and for methyl-, propyl-, and butylparabens with these mobile solvents.