Assay
Mobile phase
, Internal standard preparation, Standard preparation, and Chromatographic systemPrepare as directed in the Assay under Hydrocortisone Valerate.
Assay preparation
Transfer an accurately weighed quantity of Cream, equivalent to about 1 mg of hydrocortisone valerate, to a screw-capped tube. Add 8.0 mL of a mixture of methanol and water (3:1), and swirl to disperse. Heat at 80
for 1 minute, swirl again, and allow to cool to room temperature. Add 2.0 mL of
Internal standard solution, and mix. Centrifuge for 5 minutes, and filter, if necessary, to obtain a clear supernatant.
Procedure
Proceed as directed for
Procedure in the
Assay under
Hydrocortisone Valerate. Calculate the quantity, in mg, of hydrocortisone valerate (C
26H
38O
6), in the portion of Cream taken by the formula:
0.01C(RU / RS),
in which the terms are as defined therein.