Packaging and storage—
Preserve in tight containers. Store between 2
and 25
, excursions permitted between 15
and 30
.
[NOTE—Protect the 21-tablet pack from excessive moisture.
]
Identification—
Evaporate 50 mL of the
Assay preparation, prepared as directed in the
Assay, on a steam bath just to dryness, and dissolve the residue in 1 mL of chloroform. Proceed as directed for
Identification test
B under
Betamethasone, beginning with “Apply 10 µL of this solution.”
Dissolution, Procedure for a Pooled Sample 
711
—
Medium:
water; 900 mL. Add 1.0 mL of Internal standard solution to each vessel.
Apparatus 2:
50 rpm.
Time:
45 minutes.
Mobile phase—
Prepare a filtered and degassed mixture of methanol and water (60:40), making adjustments if necessary (see
System Suitability under
Chromatography 621).
Internal standard solution—
Prepare a solution in methanol of testosterone having a final concentration of about 0.5 mg per mL.
Standard solution—
Prepare a solution of
USP Betamethasone RS, in methanol, having an accurately known concentration of about 0.5 mg per mL. Pipet 1 mL of this solution and 1 mL of the
Internal standard solution into a container, and quantitatively dilute with water to 900 mL.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 254-nm detector and a 3.9-mm × 30-cm column that contains packing L1. The flow rate is about 2 mL per minute. Chromatograph replicate injections of the
Standard solution, and record the peak responses as directed for
Procedure: the resolution,
R, between betamethasone and testosterone is not less than 1.5; and the relative standard deviation for replicate injections is not more than 3.0%.
Procedure—
Separately inject equal volumes (about 200 µL) of the Standard solution and filtered portions of the solution under test into the chromatograph, record the chromatograms, and measure the responses for the major peaks. The relative retention times are about 0.5 for betamethasone and 1.0 for testosterone. Calculate the quantity of C22H29FO5 dissolved in comparison with the Standard solution, similarly chromatographed.
Tolerances—
Not less than 75% (Q) of the labeled amount of C22H29FO5 is dissolved in 45 minutes.
Uniformity of dosage units 905:
meet the requirements.
Procedure for content uniformity—
Test preparation—
Weigh and finely powder 1 Tablet. Transfer to a 125-mL separator, add 20 mL of water, and shake. Extract the betamethasone completely, using three 15-mL portions of chloroform, filtering each extract through chloroform-washed cotton into a 50-mL volumetric flask. Dilute with chloroform to volume, and mix. Transfer 20.0 mL of this solution to a glass-stoppered, 50-mL conical flask, evaporate the chloroform on a steam bath just to dryness, cool, and dissolve the residue in 20.0 mL of alcohol.
Procedure—
Proceed as directed under
Assay for Steroids 351, except to keep the flasks in a constant-temperature bath at 45 ± 1
for 90 minutes, then add 1.0 mL of glacial acetic acid, and cool. Calculate the quantity, in mg, of C
22H
29FO
5 in the Tablet by the formula:
(TC/D)(AU / AS),
in which
T is the labeled quantity, in mg, of betamethasone in the Tablet;
C is the concentration, in µg per mL, of
USP Betamethasone RS in the
Standard preparation; D is the concentration, in µg per mL, of betamethasone in the
Test preparation, based upon the labeled quantity per Tablet and the extent of dilution; and
AU and
AS are the absorbances of the solutions from the
Test preparation and the
Standard preparation, respectively.
Assay—
Mobile phase—
Prepare a filtered and degassed mixture of water and acetonitrile (2:1). Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Internal standard solution—
Transfer about 25 mg of beclomethasone to a 200-mL volumetric flask, add methanol to volume, and mix.
Standard preparation—
Dissolve an accurately weighed quantity of
USP Betamethasone RS in methanol, and dilute quantitatively and stepwise, if necessary, with methanol to obtain a solution having a known concentration of about 0.1 mg per mL. Mix equal volumes, accurately measured, of this solution and the
Internal standard solution to obtain a
Standard preparation having a final known concentration of about 0.05 mg of
USP Betamethasone RS per mL.
Assay preparation—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 0.5 mg of betamethasone, to a 125-mL separator. Add 25 mL of water, and shake by mechanical means for about 15 minutes. Add 5.0 mL of Internal standard solution. Extract with four 25-mL portions of chloroform. Filter the chloroform extracts through about 4 g of chloroform-washed anhydrous sodium sulfate, collecting the extracts in a 150-mL beaker. Evaporate the extracts on a steam bath with the aid of a stream of nitrogen to dryness, taking care to avoid overheating. Dissolve the residue in 2 mL of methanol, and transfer to a 10-mL volumetric flask. Rinse the beaker with small portions of methanol, transferring the rinses to the same flask. Dilute with methanol to volume, and mix.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 254-nm detector and a 4-mm × 30-cm column that contains packing L1. The flow rate is about 1.2 mL per minute. Chromatograph the
Standard preparation, and record the peak heights as directed for
Procedure: the resolution,
R, between the analyte and internal standard peaks is not less than 1.7; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 10 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the heights of the major peaks. The relative retention times are about 1.4 for beclomethasone and 1.0 for betamethasone. Calculate the quantity, in mg, of betamethasone (C
22H
29FO
5) in the portion of Tablets taken by the formula:
10C(RU / RS),
in which
C is the concentration, in mg per mL, of
USP Betamethasone RS in the
Standard preparation; and
RU and
RS are the peak height ratios obtained from the
Assay preparation and the
Standard preparation, respectively.
