Betamethasone Tablets

General Notices

Action and use

Glucocorticoid.

Definition

Betamethasone Tablets contain Betamethasone.

The tablets comply with the requirements stated under Tablets and with the following requirements.

Content of betamethasone, C₂₂H₂₉FO₅

90.0 to 110.0% of the stated amount.

Identification

A. Shake a quantity of the powdered tablets containing 25 mg of Betamethasone with 150 mL of dichloromethane for 30 minutes, filter, wash the filtrate with 20 mL of water, dry over anhydrous sodium sulfate, evaporate the solution to dryness and dry the residue at 105° for 2 hours. The infrared absorption spectrum of the residue, Appendix II A, is concordant with the reference spectrum of betamethasone (RS 029).

B. The residue obtained in test A complies with the test for the identification of steroids, Appendix III A, using impregnating solvent I and mobile phase A. At a fourth point apply to the plate 2 µL of a mixture of equal volumes of solution (1) and a 0.25% w/v solution of dexamethasone BPCRS in a mixture of 9 volumes of chloroform and 1 volume of methanol. The chromatogram obtained with this solution shows two principal spots with almost identical Rf values.

C. In the Assay, the chromatogram obtained with solution (1) shows a peak with the same retention time as the peak due to betamethasone in the chromatogram obtained with solution (2).

Tests

Uniformity of content

Tablets containing less than 2 mg and/or less than 2% w/w of Betamethasone comply with the requirements stated under Tablets using the following method of analysis. Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

(1) Finely crush one tablet, add 20 mL of a 0.002% w/v solution of hydrocortisone in methanol (50%), shake for 10 minutes and filter through a glass-fibre filter paper (Whatman GF/C is suitable).

(2) 0.0025% w/v of betamethasone BPCRS and 0.002% w/v of hydrocortisone (internal standard) in methanol (50%).

chromatographic conditions

(a) Use a stainless steel column (25 cm × 5 mm) packed with octadecylsilyl silica gel for chromatography (10 µm) (Spherisorb ODS 1 is suitable).

(b) Use isocratic elution and the mobile phase described below.

(d) Use an ambient column temperature.

(e) Use a detection wavelength of 238 nm.

(f) Inject 20 µL of each solution.

mobile phase

47 volumes of methanol and 53 volumes of water.

determination of content

Calculate the content of C₂₂H₂₉FO₅ in each tablet using the ratios of the peak areas and the declared content of C₂₂H₂₉FO₅ in betamethasone BPCRS.

Assay

For tablets containing less than 2 mg and/or less than 2% w/w of Betamethasone

Use the average of the individual results determined in the test for Uniformity of content.

For Tablets containing 2 mg or more and 2% w/w or more of Betamethasone

Weigh and powder 20 tablets. Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

(1) To a quantity of the powder containing 2.5 mg of Betamethasone add 20 mL of methanol (50%), shake for 10 minutes and filter through a glass-fibre filter paper (Whatman GF/C is suitable).

(2) 0.0125% w/v of betamethasone BPCRS and 0.010% w/v of hydrocortisone (internal standard) in methanol (50%).

(3) Prepare the solution in the same manner as solution (1) but use 20 mL of a 0.01% w/v solution of hydrocortisone in methanol (50%) in place of the 20 mL of methanol (50%).