Determination of glucocorticoids by liquid chromatography. III. Application to ointments and a cream containing cortisone acetate, dexamethasone acetate, fluorometholone, and betamethasone valerate.

Abstract

In order to separate cortisone acetate, dexamethasone acetate, fluorometholone, and betamethasone valerate in ointments and a cream from the base and excipients, a silica gel column pretreatment was carried out (pre-screening procedure) and then glucocorticoids were successfully determined by high-performance liquid chromatography on a LiChrosorb RP-18 column. By the use of the pre-screening procedure, the base, excipients, and other active ingredients (except glycyrrhetinic acid) in commercial preparations were almost completely removed, and hence a lowering of the efficiency of the LiChrosorb RP-18 column and blocking of the flow of the mobile phase in column caused by the base remaining on the top of the column could be avoided. The contents of glucocorticoids in various commercial preparations were found to be 95.7 to 102.5% of the labeled amounts.