Packaging and storage— Preserve in well-closed containers protected from light, and store in a cool, dry place.

Labeling— Label the Oral Solution in terms of zinc sulfate (ZnSO4·H2O) and in terms of elemental zinc.

Identification— The Oral Solution responds to the tests for Zinc 191 and for Sulfate 191.

pH 791: between 2.5 and 4.5.

Specific gravity 841: between 1.18 and 1.24.

Assay— Transfer to a 250-mL flask an accurately measured volume of Oral Solution, equivalent to about 99 mg of ZnSO4·H2O. Add 50 mL of water and 10 mL of ammonia–ammonium chloride buffer TS and 0.3 mL of eriochrome black TS, and titrate with 0.05 M edetate disodium VS to a green endpoint. Each mL of 0.05 M edetate disodium is equivalent to 8.973 mg of zinc sulfate (ZnSO4·H2O).

Topic/Question	Contact	Expert Committee
Monograph	Curtis Phinney 1-301-816-8540	(DSN05) Dietary Supplements - Non-Botanicals

USP32–NF27 Page 3899