Acetazolamide Tablets

General Notices

Action and use

Carbonic anhydrase inhibitor; diuretic; treatment of glaucoma, ocular hypertension, mountain sickness.

Definition

Acetazolamide Tablets contain Acetazolamide.

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

Content of acetazolamide, C4H6N4O3S2

95.0 to 105.0% of the stated amount.

Identification

A. Shake a quantity of the powdered tablets containing 0.5 g of Acetazolamide with 2 mL of 1m sodium hydroxide and filter. Neutralise the filtrate with glacial acetic acid, filter and dry the resulting precipitate at 105°. The infrared absorption spectrum of the residue, Appendix II A, is concordant with the reference spectrum of acetazolamide (RS 002).
B. Triturate a quantity of the powdered tablets containing 0.5 g of Acetazolamide with a mixture of 5 mL of water and 1 mL of 1m sodium hydroxide, transfer to a test tube, add 0.2 g of zinc powder and 0.5 mL of hydrochloric acid and immediately place a piece of lead acetate paper over the mouth of the tube. The paper exhibits a brownish black colour.
C. To a quantity of the powdered tablets containing 25 mg of Acetazolamide add 5 mL of water, 0.15 mL of 1m sodium hydroxide and 0.1 mL of weak copper sulfate solution. A greenish blue colour or precipitate is produced.

TEST

Related substances

Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions.

(1) Shake a quantity of the powdered tablets containing 50 mg of Acetazolamide for 20 minutes with 10 mL of a mixture of equal volumes of ethanol (96%) and ethyl acetate and filter.
(2) Dilute 1 volume of solution (1) to 100 volumes with the same solvent mixture as for solution (1).
chromatographic conditions
(a) Use as the coating silica gel GF254.
(b) Use a mobile phase freshly prepared as described below. Use the tank without lining the walls and allow to saturate for 1 hour before development.
(c) Apply 20 µL of each solution.
(d) Develop the plate to 15 cm.
(e) After removal of the plate, dry in air and examine under ultraviolet light (254 nm).
mobile phase

20 volumes of 13.5m ammonia, 30 volumes of ethyl acetate and 50 volumes of propan-2-ol.

limits

Any secondary spot in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (2) (1%).

Assay

Weigh and powder 20 tablets. To a quantity of the powder containing 0.4 g of Acetazolamide add 90 mL of dimethylformamide and carry out Method II for non-aqueous titration, Appendix VIII A, using 0.1m tetrabutylammonium hydroxide VS as titrant and determining the end point potentiometrically. Each mL of 0.1m tetrabutylammonium hydroxide VS is equivalent to 22.22 mg of C4H6N4O3S2.