Aluminum Acetate Topical Solution
» Aluminum Acetate Topical Solution yields, from each 100 mL, not less than 1.20 g and not more than 1.45 g of aluminum oxide (Al2O3), and not less than 4.24 g and not more than 5.12 g of acetic acid (C2H4O2), corresponding to not less than 4.8 g and not more than 5.8 g of aluminum acetate (C6H9AlO6). Aluminum Acetate Topical Solution may be stabilized by the addition of not more than 0.6 percent of Boric Acid.
Add the Glacial Acetic Acid to the Aluminum Subacetate Topical Solution and sufficient water to make 1000 mL. Mix, and filter, if necessary.
[noteDispense only clear Aluminum Acetate Topical Solution. ]
Packaging and storage Preserve in tight containers.
Identification It responds to the tests for Aluminum 191 and for the ferric chloride test for Acetate 191 with a deep red color upon the addition of ferric chloride TS. This color is destroyed by the addition of a mineral acid.
pH 791: between 3.6 and 4.4.
Limit of boric acid Pipet 25 mL into 75 mL of water in a conical flask. Add 3 mL of phenolphthalein TS, then add 0.5 N sodium hydroxide VS from a buret until a faint pink color is obtained. Heat to boiling, and again neutralize. Add 150 mL of glycerin to the neutralized solution, and titrate with 0.5 N sodium hydroxide VS. Perform a blank determination in a similar manner. From the volume of 0.5 N sodium hydroxide VS used after the addition of the glycerin, subtract the volume used in the blank. Each mL of 0.5 N sodium hydroxide is equivalent to 30.92 mg of H3BO3.
Heavy metals 231 Dilute 2 mL of it with water to 25 mL: the limit is 0.001%.
Assay for aluminum oxide
Procedure Pipet 25 mL of Topical Solution into a 250-mL volumetric flask, add 5 mL of hydrochloric acid, dilute with water to volume, and mix. Pipet 25 mL of this solution into a 250-mL beaker, and add, in the order named and with continuous stirring, 25.0 mL of Edetate disodium titrant and 20 mL of acetic acidammonium acetate buffer TS, then heat the solution near the boiling point for 5 minutes. Cool, and add 50 mL of alcohol and 2 mL of dithizone TS. Titrate the solution with 0.05 M zinc sulfate VS to a bright rose-pink color. Perform a blank determination, substituting water for the sample, and make any necessary correction. Each mL of 0.05 M Edetate disodium titrant is equivalent to 2.549 mg of Al2O3.
Assay for acetic acid Pipet 20 mL of Topical Solution into a Kjeldahl flask containing a mixture of 20 mL of phosphoric acid and 150 mL of water. Connect the flask to a condenser, the delivery tube from which dips beneath the surface of 50.0 mL of 0.5 N sodium hydroxide VS contained in a receiving flask. Distill about 160 mL, then remove the delivery tube from below the surface of the liquid, allow the distilling flask to cool, add 50 mL of water, and distill an additional 40 to 45 mL into the receiving flask. Add phenolphthalein TS to the distillate, and titrate the excess 0.5 N sodium hydroxide VS with 0.5 N sulfuric acid VS. Each mL of 0.5 N sodium hydroxide is equivalent to 30.03 mg of C2H4O2.
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USP35NF30 Page 2126Pharmacopeial Forum: Volume No. 34(2) Page 242