A: Cut open 1Capsule,and remove the contents:the Capsule contents respond to Identificationtest Aunder Dihydrotachysterol Oral Solution.

B: The retention time of the major peak in the chromatogram of the Assay preparationcorresponds to that of the Standard preparationobtained as directed in the Assay.

Mobile phase ,Standard preparation,System suitability preparation,and Chromatographic system—Prepare as directed in the Assayunder Dihydrotachysterol.

Assay preparation— Combine the contents of not less than 20Capsules.Transfer an accurately weighed quantity of Capsule contents,equivalent to about 500µg of dihydrotachysterol,to a 50-mLvolumetric flask,dissolve in 25mLof Mobile phase,and mix.Dilute with Mobile phaseto volume,and mix.

Procedure— Proceed as directed for Procedurein the Assayunder Dihydrotachysterol.Calculate the quantity,in µg,of C28H46Oin the portion of Capsules taken by the formula: in which Cis the concentration,in µg per mL,of USP Dihydrotachysterol RSin the Standard preparation,and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.