Methanolic sodium chloride , Mobile phase, Internal standard solution, Standard preparation, and Chromatographic system—Prepare as directed in the Assay under Flurandrenolide Cream.

Assay preparation— Transfer an accurately weighed portion of Lotion, calculated from the density to contain about 500 µg of flurandrenolide, to a separator. (Determine the density by taring a 100-mL volumetric flask containing 50.0 mL of water, adding approximately 25 g of well-shaken Lotion, and again weighing, then carefully adjusting the contents of the volumetric flask with water from a buret to volume, and finally calculating the density taken by the formula: in which A is the weight, in g, of the Lotion taken; and B is 50.0 mL minus the volume, in mL, of water necessary to adjust the contents of the volumetric flask to volume.) Proceed as directed for Assay preparation in the Assay under Flurandrenolide Cream, beginning with “Add 50 mL of hexane and 25 mL of Methanolic sodium chloride.”

Procedure— Proceed as directed in the Assay under Flurandrenolide Cream. Calculate the quantity, in mg, of flurandrenolide (C24H33FO6) in each mL of the Lotion taken by the formula: in which C is the concentration, in mg per mL, of USP Flurandrenolide RS in the Standard preparation; D is the density of the Lotion; W is the weight, in g, of Lotion taken; and RU and RS are the peak response ratios obtained from the Assay preparation and the Standard preparation, respectively.