Mafenide Acetate Cream

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

Mafenide Acetate Cream is Mafenide Acetate in a water-miscible, oil-in-water cream base, containing suitable preservatives. It contains NLT 90.0% and NMT 110.0% of mafenide acetate (C₇H₁₀N₂O₂S · C₂H₄O₂), in terms of the labeled amount of mafenide (C₇H₁₀N₂O₂S).

2 IDENTIFICATION

Change to read:

A. Spectroscopic Identification Tests 〈197〉, Ultraviolet-Visible Spectroscopy: 197U (CN 1-May-2020)

Sample solution: Proceed as directed in the Assay.

Acceptance criteria: Meets the requirements

B. Identification Tests—General, Acetate〈191〉

Sample solution: Place about 1 g in a 60-mL separatory funnel, and add 20 mL of chloroform to dissolve it. Add 20 mL of water, shake for 2 min, allow the layers to separate completely, and discard the lower chloroform layer. Repeat this washing with another 20-mL portion of chloroform, and discard the chloroform washing. Centrifuge the aqueous layer. Use a 1-mL aliquot of the supernatant with 2 mL of water for test A and a 3-mL aliquot of the supernatant test B.

Acceptance criteria: Meets the requirements

3 ASSAY

Procedure

Standard solution: 200 μg/mL of USP Mafenide Acetate RS in 0.01 N hydrochloric acid

Sample solution: Nominally 200 μg/mL of mafenide acetate prepared as follows. Transfer a portion of Cream containing 100 mg of mafenide acetate to a 60-mL separator, and add 20 mL of chloroform to dissolve it. Add 20 mL of water, shake for 2 min, allow the layers to separate completely, and discard the lower chloroform layer. Repeat this washing with two separate 20-mL portions of chloroform, and discard the chloroform washings. Pass the aqueous phase through a dry filter into a 100-mL volumetric flask. Rinse the separator and the filter with water, passing all rinses through the filter, and add water to volume. Centrifuge 30 mL, then pipet 20 mL of the clear supernatant into a 100-mL volumetric flask. Add 1 mL of 1 N hydrochloric acid, and add water to volume.

Instrumental conditions

Mode: UV

Analytical wavelength: 267 nm

Cell: 1 cm

Blank: 0.01 N hydrochloric acid

Analysis

Samples: Standard solution, Sample solution, and Blank

Calculate the percentage of the labeled amount of mafenide acetate (C₇H₁₀N₂O₂S · C₂H₄O₂) in the portion of Cream taken:

Result = (A_U/A_S) × (C_S/C_U) × 100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

C_S = concentration of USP Mafenide Acetate RS in the Standard solution (μg/mL)

C_U = nominal concentration of mafenide acetate in the Sample solution (μg/mL)

Acceptance criteria: 90.0%–110.0%

4 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers, and avoid exposure to excessive heat.

USP Reference Standards 〈11〉

USP Mafenide Acetate RS