Bacitracin Zinc Soluble Powder

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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Bacitracin Zinc Soluble Powder is a mixture of Bacitracin Zinc and zinc proteinates. It contains not less than 90.0 percent and not more than 120.0 percent of the labeled amount of bacitracin.

1 Packaging and storage

Preserve in tight containers.

2 Labeling

Label it to indicate that it is for veterinary use only. Label it to state the content of bacitracin in terms of grams per pound, each gram of bacitracin being equivalent to 42,000 Bacitracin Units.

USP REFERENCE STANDARDS (11)-

USP Bacitracin Zinc BS

LOSS ON DRYING (731)-Dry about 100 mg, accurately weighed, in a capillary-stoppered bottle in vacuum at a pressure not exceeding 5 mm of mercury at 60 for 3 hours: it loses not more than 5.0% of its weight.

3 Zinc content

Using Powder, proceed as directed for Zinc content under Bacitracin Zinc. Calculate the zinc content, in g, in relation to each 42,000 Bacitracin Units in the specimen taken by the formula:

280,000C/WA

in which A is the bacitracin content of the specimen, in Bacitracin Units per g, and the other terms are as defined therein: it contains not more than 2.0 g for each 42,000 Bacitracin Units.

4 Assay

Dissolve an accurately weighed quantity of Powder quantitatively in 0.01 N hydrochloric acid to obtain a stock solution containing about 100 Bacitracin Units per mL. Proceed as directed under Antibiotics-Microbial Assays (81), using an accurately measured volume of this stock solution diluted quantitatively and stepwise with Buffer B. 1 to obtain a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard. In preparing each test dilution of the Standard, add additional hydrochloric acid to each to obtain the same concentration of hydrochloric acid as in the Test Dilution.