Zinc Sulfate Compounded Injection

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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1 DEFINITION

Zinc Sulfate Compounded Injection contains NLT 90.0% and NMT 110.0% of the labeled content of zinc (Zn). Prepare Zinc Sulfate Compounded Injection containing 1 mg/mL or 5 mg/mL of zinc as follows (see Pharmaceutical Compounding—Sterile Preparations 〈797〉).

For Zinc Sulfate Compounded Injection containing 1-mg/mL

For Zinc Sulfate Compounded Injection containing 5-mg/mL

Dissolve the Zinc Sulfate Monohydrate or the Zinc Sulfate Heptahydrate in 95 mL of Sterile Water for Injection. Adjust with Sulfuric Acid or Sodium Hydroxide to a pH between 2.0 and 4.0. Add sufficient Sterile Water for Injection to bring to final volume, and mix well. Pass through a compatible filter of 1.2-μm pore size to remove particulate matter and sterilize by autoclave.

2 ASSAY

Procedure

Mobile phase: 3 mM nitric acid

Standard solution: 0.01 mg/mL of zinc prepared from USP Zinc Sulfate RS and water

Sample solution: For a 1-mg/mL Injection, transfer 1.0 mL of the compounded preparation to a 100-mL volumetric flask, dilute with water to volume, and mix well. For a 5-mg/mL Injection, transfer 0.2 mL of the compounded preparation to a 100-mL volumetric flask, dilute with water to volume, and mix well.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: Conductivity

Column: 4.0-mm × 10-cm; packing L76

Column temperature: 40°

Flow rate: 0.9 mL/min

Injection volume: 10 μL

System suitability

Sample: Standard solution

[Note—The retention time for zinc is about 7.0 min.]

Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0% for replicate injections

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of zinc (Zn) in the portion of Injection taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response of zinc from the Sample solution

r_S = peak response of zinc from the Standard solution

C_S = concentration of zinc from USP Zinc Sulfate RS in the Standard solution (mg/mL)

C_U = nominal concentration of zinc in the Sample solution (mg/mL)

Acceptance criteria: 90.0%–110.0%

3 SPECIFIC TESTS

pH 〈791〉: 2.0–4.0

Sterility Tests 〈71〉, Test for Sterility of the Product to Be Examined, Membrane Filtration: Meets the requirements

Bacterial Endotoxins Test 〈85〉: NMT 25.0 USP Endotoxin Units/mg of zinc

Particulate Matter in Injections 〈788〉: Meets the requirements

4 ADDITIONAL REQUIREMENTS

Packaging and Storage: Package in single-dose sterile containers, preferably of Type I or Type II glass, and store at controlled roomtemperature.

Beyond-Use Date: In the absence of performing and completing a sterility and endotoxins test, the Beyond-Use Dates in Pharmaceutical

Compounding - Sterile Preparations 〈797〉 apply. After successful completion of sterility and endotoxins testing, NMT 90 days after the date on which it was compounded when stored at controlled room temperature.

Labeling: Label it to indicate that it is for use in a single patient only, and to state the Beyond-Use Date. Label the Injection in terms of its

content of anhydrous zinc sulfate (ZnSO₄) and in terms of its content of elemental zinc. Label it to state that it is not intended for direct injection but is to be added to other intravenous solutions.

USP Reference Standards 〈11〉

USP Zinc Sulfate RS (USP 1-Aug-2020)