Bacitracin Ointment

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

Bacitracin Ointment is Bacitracin in an anhydrous ointment base. It contains NLT 90.0% and NMT 140.0% of the labeled amount of bacitracin. It may contain a suitable anesthetic.

2 IDENTIFICATION

A. THIN-LAYER CHROMATOGRAPHIC IDENTIFICATION TEST (201BNP): Meets the requirements

3 ASSAY

PROCEDURE

(See Antibiotics-Microbial Assays (81).)

Sample solution: Use a portion of Ointment shaken with about 50 mL of ether in a separator and extracted with four 20-mL portions of Buffer B.1 (see the chapter). Combine the buffer extracts, and dilute with Buffer B.1 to a suitable volume.

Analysis: Proceed as directed in the chapter. Add sufficient 0.01 N hydrochloric acid to a suitable aliquot of the Sample solution so that the amount of hydrochloric acid in the Test Dilution is the same as in the median level of the standard. Dilute with Buffer B. 1 to obtain a Test Dilution having a bacitracin concentration that is nominally equivalent to the median level of the standard.

Acceptance criteria: 90.0%-140.0%

4 SPECIFIC TESTS

WATER DETERMINATION, Method (921)

Analysis: Use 20 mL of a mixture of toluene and methanol (7:3) in place of methanol in the titration vessel.

Acceptance criteria: NMT 0.5%

MINIMUM FILL (755): Meets the requirements

5 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in well-closed containers containing NMT 60 g, unless labeled solely for hospital use, preferably at controlled room temperature.

USP REFERENCE STANDARDS (11)

USP Bacitracin Zinc RS