Packaging and storage—
Preserve in tight,light-resistant containers.
Identification—
Transfer the contents of a number of Capsules,equivalent to about 150µg of calcifediol,to a suitable container,add 1mLof methanol,and shake vigorously for 1minute.Separate the layers by centrifugation,and transfer as much of the top,methanol layer as possible to a second container.Evaporate this extract to dryness,and dissolve the residue in about 1mLof chloroform.Proceed as directed under
Thin-layer Chromatographic Identification Test á201ñ,applying 20µLof this solution and 20µLof a solution containing about the same concentration of
USP Calcifediol RSin chloroform,and using a solvent system consisting of 60parts of cyclohexane and 40parts of ethyl acetate.
Dissolution á711ñ—
Medium:
water;500mL.
Apparatus 2:
50rpm.
Time:
15minutes.
Procedure—
Place 1Capsule in each vessel,and allow the Capsule to sink to the bottom of the vessel before starting rotation of the blade.Observe the Capsules,and record the time taken for each capsule shell to rupture.
Tolerances—
The requirements are met if all of the Capsules tested rupture in not more than 15minutes.If 1or 2of the Capsules rupture in more than 15but not more than 30minutes,repeat the test on 12additional Capsules.Not more than 2of the total of 18Capsules tested rupture in more than 15but not more than 30minutes.
Assay—
Internal standard solution—
Dissolve testosterone in ethyl acetate to obtain a solution having a concentration of about 35µg per mL.
Standard preparation—
Dissolve an accurately weighed quantity of
USP Calcifediol RSin
Internal standard solution,and dilute quantitatively and stepwise with
Internal standard solutionto obtain a solution having a known concentration of about 7µg of
USP Calcifediol RSper mL.
Assay preparation—
Transfer a number of Calcifediol Capsules to a suitable container.Using a suitable implement,shear open a number of Capsules inside the container.Wash the implement with an accurately measured volume of Internal standard solutionthat will yield a solution having a concentration of about 7µg of calcifediol per mL.Collect the rinsings in the container,and mix to obtain a homogeneous solution of the Capsule contents.
Chromatographic system
and
System suitability—Proceed as directed in the
Assayunder
Calcifediol.
Procedure—
Proceed as directed for
Procedurein the
Assayunder
Calcifediol.Calculate the quantity,in µg,of C
27H
44O
2·H
2Oin the portion of Capsule contents taken by the formula:
CVU(RU/RS),
in which
Cis the concentration,in µg per mL,of
USP Calcifediol RSin the
Standard preparation;VUis the volume,in mL,of
Internal standard solutiontaken for the
Assay preparation;and
RUand
RSare the peak response ratios of calcifediol to testosterone obtained from the
Assay preparationand the
Standard preparation,respectively.