原文:Pass a sufficient quantity of the powder prepared for use in the Assay through a sieve with a nominal mesh aperture of 150 ?m. 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.
计算: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.