Neomycin Sulfate and Prednisolone Acetate 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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Neomycin Sulfate and Prednisolone Acetate Ointment contains the equivalent of not less than 90.0 percent and not more than 135.0 percent of the labeled amount of neomycin, and not less than 90.0 percent and not more than 110.0 percent of the labeled amount of prednisolone acetate (C₂₃H₃₀O₆).

Packaging and storage-Preserve in collapsible tubes or in tight containers, protected from light.

USP REFERENCE STANDARDS (11)

USP Neomycin Sulfate RS

USP Prednisolone Acetate RS

1 Identification

A: It meets the requirements for neomycin under Thin-Layer Chromatographic Identification Test (201BNP).

B: The retention time of the major peak for prednisolone acetate in the chromatogram of the Assay preparation corresponds to that of the Standard preparation, as obtained in the Assay for prednisolone acetate,

MINIMUM FILL (755): meets the requirements.

WATER DETERMINATION, Method | (921): not more than 1.0%, 20 mL of a mixture of toluene and methanol (7:3) being used in place of methanol in the titration vessel.

Assay for neomycin-Proceed with Ointment as directed in the Assay under Neomycin Sulfate Ointment.

2 Assay for prednisolone acetate

Mobile phase, Internal standard solution, Standard preparation, and Chromatographic system-Prepare as directed in the Assay for prednisolone acetate under Neomycin Sulfate and Prednisolone Acetate Ophthalmic Suspension.

Assay preparation-Transfer an accurately weighed portion of Ointment, equivalent to about 1 mg of prednisolone acetate, to a suitable container, add 2.0 mL of Internal standard solution, dilute with water-saturated chloroform to about 35 mL, and shake to dissolve the ointment. Transfer about 5 mL of this solution to a suitable container, and evaporate to dryness. Add about 5 mL of water-saturated chloroform, and sonicate for 5 minutes. Filter, and use the clear solution as the Assay preparation.

Procedure-Proceed as directed for Procedure in the Assay for prednisolone acetate under Neomycin Sulfate and Prednisolone Acetate Ophthalmic Suspension. Calculate the quantity, in mg, of prednisolone acetate (C₂₃H₃₀O₆) in the portion of Ointment taken by the formula:

0.04C(R_u /R_s )

in which C is the concentration, in µg per mL, of USP Prednisolone Acetate RS in the Standard preparation, and R_u and R_s are the peak response ratios of prednisolone acetate to betamethasone obtained from the Assay preparation and the Standard preparation, respectively.