Aluminum Sulfate and Calcium Acetate Tablets for Topical Solution
» Aluminum Sulfate and Calcium Acetate Tablets for Topical Solution contain not less than 90.0 percent and not more than 110.0 percent of the labeled amounts of aluminum sulfate tetradecahydrate [Al2(SO4)3·14H2O] and calcium acetate monohydrate (C4H6CaO4·H2O).
Packaging and storage— Preserve in tight containers, and avoid excessive heat.
A: Suspend 2 g of ground Tablet powder in 50 mL of water, and filter. Mix 2 mL of the filtrate with 2 mL of water and 2 drops of 3 N hydrochloric acid: the solution responds to the ammonium hydroxide test for Aluminum 191. [note—Retain the remaining filtrate for Identification test B. ]
B: A portion of the filtrate retained from Identification test A responds to the tests for Sulfate 191 and for Calcium 191.
Disintegration 701: 10 minutes.
Uniformity of dosage units 905: meet the requirements for Weight Variation.
pH 791: between 4.0 and 4.8, in a solution (2 g of ground Tablet powder in 500 mL of water).
Loss on drying 731 Dry ground Tablet powder at 150 for 15 minutes: it loses not more than 18% of its weight.
Assay for aluminum sulfate—
Assay preparation— Finely powder and mix not fewer than 20 Tablets. Weigh accurately a portion of the powder, equivalent to about 2.8 g of aluminum sulfate, and transfer to a 1000-mL volumetric flask. Add 100 mL of 1.2 N hydrochloric acid and 100 mL of water, and heat on a steam bath, with occasional swirling, to dissolve the powder. Allow the solution to cool, dilute with water to volume, and mix. [note—Retain a portion of this Assay preparation for the Assay for calcium acetate. ]
Procedure— Transfer 25.0 mL of the Assay preparation to a 250-mL conical flask. Add 40.0 mL of 0.01 M edetate disodium VS and 20 mL of acetic acid–ammonium acetate buffer TS, and mix by swirling. Add 50 mL of alcohol and 2 mL of dithizone TS, and titrate with 0.02 M zinc sulfate VS until the color changes from green-violet to a clear rose-pink. Perform a blank determination, substituting 25 mL of water for the Assay preparation, and make any necessary correction. Each mL of 0.01 M edetate disodium is equivalent to 2.972 mg of Al2(SO4)3·14H2O.
Assay for calcium acetate— Transfer 20.0 mL of the Assay preparation retained from the Assay for aluminum sulfate to a 125-mL conical flask. With constant stirring, add in the order named, about 0.5 mL of trolamine, 10 mL of ammonia–ammonium chloride buffer TS, and 3 drops of a solution prepared by dissolving 500 mg of eriochrome black T trituration in 10 mL of methanol, and titrate with 0.01 M edetate disodium VS to a violet endpoint. Each mL of 0.01 M edetate disodium is equivalent to 1.762 mg of C4H6CaO4·H2O.
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