Chewable Aluminium Hydroxide Tablets
Definition
Chewable Aluminium Hydroxide Tablets contain, in each, 500 mg of Dried Aluminium Hydroxide in a suitable basis with a peppermint flavour.
Content of aluminium oxide, Al2O3
Not less than the equivalent of 0.225 g.
Identification
The powdered tablets yield the reaction characteristic of aluminium salts, Appendix VI.
Tests
Disintegration
The requirement for Disintegration does not apply to Chewable Aluminium Hydroxide Tablets.
Neutralising capacity
Pass a sufficient quantity of the powder prepared for use in the Assay through a sieve with a nominal mesh aperture of 150 µm. Mix a quantity of the powder containing 0.5 g of Dried Aluminium Hydroxide with a small quantity of water to give a smooth paste and slowly add further quantities of water to a total volume of 100 mL. Warm to 37°, add 100 mL of 0.1m hydrochloric acid VS previously heated to 37° and stir continuously, maintaining the temperature at 37°. The pH of the solution at 37° after 10, 15 and 20 minutes is not less than 1.6, 1.8 and 2.2 respectively and at no time during this period is it more than 4.0. Add 10 mL of 0.5m hydrochloric acid VS previously heated to 37°, stir continuously for 1 hour maintaining the temperature at 37° and titrate the solution with 0.1m sodium hydroxide VS to pH 3.5. Subtract the volume of 0.1m sodium hydroxide VS from 150 to obtain the number of mL of 0.1m hydrochloric acid VS required for the neutralisation. Calculate the number of mL of 0.1m hydrochloric acid VS required for the total weight of the tablets taken for the Assay and divide by the number of tablets. The result is not less than 115.
Assay
Weigh and powder 20 tablets, avoiding frictional heating. Dissolve a quantity of the powder containing 0.4 g of Dried Aluminium Hydroxide as completely as possible in a mixture of 3 mL of hydrochloric acid and 3 mL of water by warming on a water bath, cool to below 20° and dilute to 100 mL with water. To 20 mL of this solution add 40 mL of 0.05m disodium edetate VS, 80 mL of water and 0.15 mL of methyl red solution and neutralise by the drop wise addition of 1m sodium hydroxide VS. Heat on a water bath for 30 minutes, add 3 g of hexamine and titrate with 0.05m lead nitrate VS using 0.5 mL of xylenol orange solution as indicator. Each mL of 0.05m disodium edetate VS is equivalent to 2.549 mg of Al2O3.