Zinc Sulfate Tablets
» Zinc Sulfate Tablets contain not less than 95.0 percent and not more than 105.0 percent of the labeled amount of ZnSO4·H2O. It may contain one or more suitable flavors and sweeteners.
Packaging and storage— Preserve in well-closed containers, and store at controlled room temperature.
Labeling— Label the Tablets in terms of zinc sulfate (ZnSO4·H2O) and in terms of elemental zinc.
Identification—
Test solution— Dissolve a portion of powdered Tablets in water to obtain a solution containing about 0.05 g of zinc sulfate per mL.
Glycerin solution: a mixture of glycerin and water (85:15).
Sodium sulfide solution— Dissolve 12 g of sodium sulfide with heating in a 45-mL mixture of Glycerin solution and water (29:10), allow to cool, and dilute with the same mixture of solvents to 100 mL. The solution should be colorless.
Hydrochloric acid solution —Transfer 20 g of hydrochloric acid to a 100-mL volumetric flask, dilute with water to volume, and mix.
Barium chloride solution— Transfer 61 g of barium chloride to a 1000-mL volumetric flask, dissolve in and dilute with water to volume, and mix.
Sodium hydroxide solution— Transfer 42 g of sodium hydroxide to a 100-mL volumetric flask, dilute with water to volume, and mix.
Ammonium chloride solution— Transfer 107 g of ammonium chloride to a 1000-mL volumetric flask, dilute with water to volume, and mix.
A: To 5 mL of the Test solution add 1 mL of Hydrochloric acid solution and 1 mL of Barium chloride solution. A white precipitate is formed.
B: To 5 mL of the Test solution add 0.2 mL of Sodium hydroxide solution. A white precipitate is formed. Add an additional 2 mL of Sodium hydroxide solution and the precipitate dissolves. Add 10 mL of Ammonium chloride solution and the solution remains clear. Add 0.1 mL of Sodium sulfide solution and a white precipitate is formed
Disintegration 701: 60 seconds.
Uniformity of dosage units 905: meet the requirements.
Assay— Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 90 mg of zinc, to a 200-mL volumetric flask. Dissolve in 15 mL of dilute acetic acid, and sonicate for 15 minutes. Dilute with water to volume, and mix. Add 50 mg of xylenol orange triturate to the solution, and mix. Neutralize the solution with about 2 g of methenamine until the solution is a violet-pink color. Titrate with 0.1 M edetate disodium VS until the solution is yellow. Each mL of 0.1 M edetate disodium VS is equivalent to 17.946 mg of ZnSO4·H2O.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Curtis Phinney

1-301-816-8540		 (DSN05) Dietary Supplements - Non-Botanicals
701 Margareth R.C. Marques, Ph.D.
Senior Scientist
1-301-816-8106		 (BPC05) Biopharmaceutics05
USP32–NF27 Page 3900
Pharmacopeial Forum: Volume No. 31(1) Page 82