Zinc Sulfate Oral Solution
DEFINITION
Zinc Sulfate Oral Solution contains NLT 90.0% and NMT 110.0% of the labeled amount of zinc sulfate monohydrate (ZnSO4·H2O). It may contain one or more suitable flavors and sweeteners.
IDENTIFICATION
• Identification Tests—General, Zinc 
191
and Sulfate 191:
Meets the requirements
191 and Sulfate 191:
Meets the requirements
ASSAY
• Procedure
Sample:
An accurately measured volume of Oral Solution, equivalent to 99 mg of zinc sulfate monohydrate (ZnSO4·H2O)
Blank:
60 mL of water and 10 mL of ammonia–ammonium chloride buffer TS. Add 0.1 mL of eriochrome black TS.
Titrimetric system
(See Titrimetry 541.)
541.)
Mode:
Direct titration
Titrant:
0.05 M edetate disodium VS
Endpoint detection:
Visual
Analysis:
Transfer the Sample to a 250-mL flask. Add 50 mL of water and 10 mL of ammonia–ammonium chloride buffer TS and 0.3 mL of eriochrome black TS. Titrate with Titrant to a green endpoint.
Calculate the percentage of the labeled amount of zinc sulfate monohydrate (ZnSO4·H2O) in the portion of Oral Solution taken:
Result = {[(VS 
VB) × M × F]/W} × 100
VB) × M × F]/W} × 100| VS | = | = Titrant volume consumed by the Sample (mL) |
| VB | = | = Titrant volume consumed by the Blank (mL) |
| M | = | = actual molarity of the Titrant (mM/mL) |
| F | = | = equivalency factor, 179.46 mg/mM |
| W | = | = nominal amount of zinc sulfate monohydrate in the Sample (mg) |
Acceptance criteria:
90.0%–110.0%
SPECIFIC TESTS
• Specific Gravity 841:
1.18–1.24
841:
1.18–1.24
• pH 791:
2.5–4.5
791:
2.5–4.5
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers, and store in a cool, dry place protected from light.
• Labeling:
Label the Oral Solution in terms of zinc sulfate monohydrate (ZnSO4·H2O) and in terms of elemental zinc.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Natalia Davydova
Scientific Liaison 1-301-816-8328 |
(DS2010) Monographs - Dietary Supplements |
USP35–NF30 Page 5077
Pharmacopeial Forum: Volume No. 31(2) Page 468