Liquid chromatographic assay for diflorasone diacetate in cream and ointment formulations.

A high-performance liquid chromatographic assay for quantitating diflorasone diacetate (I) in cream and ointment formulations and in bulk form is described. Isoflupredone acetate (II) was used as the internal standard and a 3-micron silica gel column with a mobile phase comprised of water-saturated butyl chloride-water-saturated methylene chloride-tetrahydrofuran-acetic acid (350:125:10:15) led to an efficient separation. The method gave accurate results for four formulations, two creams and two ointments, as well as the bulk drug. The assay has an RSD of approximately 1.8% for the cream formulations, 1.3% for the ointment formulations, and 1.0% for the bulk drug. The method is specific for I and capable of resolving structurally related compounds.