» Betamethasone Tablets contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of betamethasone (C22H29FO5).
Packaging and storage Preserve in tight containers. Store between 2 and 25, excursions permitted between 15 and 30. [noteProtect the 21-tablet pack from excessive moisture. ]
USP Reference standards 11
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
Standard preparation Prepare as directed under Assay for Steroids 351, using USP Betamethasone RS, to obtain a solution having a known concentration of about 12 µg per mL instead of 10 µg per mL.
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 C22H29FO5 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.
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 (C22H29FO5) 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.
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USP35NF30 Page 2338Pharmacopeial Forum: Volume No. 30(1) Page 62