Brompheniramine Tablets

Histamine H₁ receptor antagonist; antihistamine.

Brompheniramine Tablets contain Brompheniramine Maleate.

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

95.0 to 105.0% of the stated amount.

In the test for Related substances the retention time of the principal peak in the chromatogram obtained with solution (2) is similar to that of the principal peak in the chromatogram obtained with solution (3).

Carry out the method for gas chromatography, Appendix III B.

(1) Shake a quantity of the powdered tablets containing 20 mg of Brompheniramine Maleate with 5 mL of water for 5 minutes, make the resulting suspension alkaline by adding 13.5m ammonia drop wise, add 2.5 mL of toluene, shake for a further 5 minutes, centrifuge and use the upper, toluene layer.

(2) Dilute 1 volume of solution (1) to 50 volumes with dichloromethane.

(3) 0.016% w/v of brompheniramine maleate EPCRS in dichloromethane.

(4) 0.5% w/v of brompheniramine maleate EPCRS and 0.25% w/v of chlorphenamine maleate BPCRS in dichloromethane.

(a) Use a glass column (2.3 m × 2 mm) packed with acid and base-washed, silanised diatomaceous support (135 µm to 175 µm) (Chromosorb W AW-DMCS is suitable) impregnated with 3% w/w of polymethylphenylsiloxane (50% phenyl) (OV 17 is suitable).

(b) Use helium as the carrier gas at 1.7 mL per minute.

(c) Use isothermal conditions maintained at 205°.

(d) Use an inlet temperature of 250°.

(e) Use a flame ionisation detector at a temperature of 250°.

(f) Inject 1 µL of each solution.

(g) For solution (1), continue the chromatography for at least 2.5 times the retention time of the principal peak.

The test is not valid unless, in the chromatogram obtained with solution (4), the resolution factor between the peaks corresponding to brompheniramine and chlorpheniramine is at least 1.5.

In the chromatogram obtained with solution (1):

no secondary peak has an area greater than 0.4% of the area of the principal peak;

the sum of the areas of any secondary peaks is not greater than 1% of the area of the principal peak.

Disregard any peak with an area less than 0.1% of that of the principal peak in the chromatogram obtained with solution (1).

Weigh and powder 20 tablets. Shake a quantity of the powder containing 4 mg of Brompheniramine Maleate with 50 mL of water for 10 minutes, adjust the pH to 11.0 with 0.1m sodium hydroxide and cool to room temperature. Extract the mixture with two 75-mL quantities of petroleum spirit (boiling range, 40° to 60°). Extract the combined extracts with three 50-mL quantities of 1m hydrochloric acid, combine the acidic extracts and add sufficient 1m hydrochloric acid to produce 200 mL. Measure the absorbance of the resulting solution at the maximum at 265 nm, Appendix II B. Calculate the content of C₁₆H₁₉BrN₂,C₄H₄O₄ taking 199 as the value of A(1%, 1 cm) at the maximum at 265 nm.

Brompheniramine Tablets should be protected from light.