Neomycin and Polymyxin B Sulfates and Hydrocortisone Otic Solution

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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Neomycin and Polymyxin B Sulfates and Hydrocortisone Otic Solution is a sterile solution containing the equivalent of not less than 90.0 percent and not more than 130.0 percent of the labeled amounts of neomycin and polymyxin B. It contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of hydrocortisone. It may contain one or more suitable buffers, dispersants, and solvents.

Packaging and storage-Preserve in tight, light-resistant containers. The containers or individual cartons are sealed and tamper-proof so that sterility is assured at time of first use.

USP REFERENCE STANDARDS (11)-

USP Hydrocortisone RS

USP Neomycin Sulfate RS

USP Polyrnvxin B Sulfate RS

STERILITY TESTS (71): meets the requirements.

PH (791): between 2.0 and 4.5.

Assay for neomycin-Proceed as directed under Antibiotics-Microbial Assays (81), using an accurately measured volume of Otic Solution diluted quantitatively and stepwise with Buffer B.3 to yield a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard (1.0 µg of neomycin per mL).

Assay for polymyxin B-Proceed as directed under Antibiotics-Microbial Assays (81), using an accurately measured volume of Otic Solution diluted quantitatively and stepwise with Buffer B.6 to yield a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard (10 Polymyxin B Units per mL). Add to each test dilution of the Standard a quantity of Neomycin Standard, dissolved in Buffer 8.6, to obtain the same concentration of neomycin present in the Test Dilution.

Assay for hydrocortisone-

Mobile phase, Standard preparation, and Chromatographic system-Prepare as directed in the Assay for hydrocortisone under Neomycin and Polymyxin B Sulfates. Bacitracin Zinc and Hydrocortisone Ophthalmic Ointment.

Assay preparation-Transfer 3.0 mL of Otic Solution to a 200-mL volumetric flask, dilute with a mixture of methanol and water (1:1) to volume, and mix.

Procedure-Proceed as directed for Procedure in the Assay for hydrocortisone under Neomycin and Polymyxin B Sulfates, Bacitracin Zinc and Hydrocortisone Ophthalmic Ointment. Calculate the quantity, in mg, of C₂₁H₃₀O₅ in each mL of the Otic Solution taken by the formula:

(66.67C)(r_u /r_s )

in which C is the concentration, in mg per ml, of USP Hydrocortisone RS in the Standard preparation, and r_u and r_s are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.