Mafenide Acetate

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

DOWNLOAD PDF HERE

1 DEFINITION

Mafenide Acetate contains NLT 98.0% and NMT 102.0% of mafenide acetate (C₇H₁₀N₂O₂S · C₂H₄O₂), calculated on the anhydrous basis.

2 IDENTIFICATION

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K

B. The R value of the principal spot of the Identification solution corresponds to that of Standard solution A, as obtained in the test for Organic Impurities.

3 ASSAY

Change to read:

Procedure

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

Sample stock solution: 2 mg/mL of Mafenide Acetate

Sample solution: 200 μg/mL of Mafenide Acetate prepared as follows. Pipet 10 mL of the Sample stock solution into a 100-mL volumetric flask containing 1 mL of 1 N hydrochloric acid, and dilute with water to volume.

Instrumental conditions

(See Ultraviolet-Visible Spectroscopy 〈857〉.) (USP 1-Dec-2021)

Mode: UV

Analytical wavelength: 267 nm

Cell: 1 cm

Blank: 0.01 N hydrochloric acid

Analysis

Samples: Standard solution and Sample solution (USP 1-Dec-2021)

Calculate the percentage of mafenide acetate (C₇H₁₀N₂O₂S · C₂H₄O₂) in the portion of Mafenide Acetate 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 = concentration of Mafenide Acetate in the Sample solution (μg/mL)

Acceptance criteria: 98.0%–102.0% on the anhydrous basis

4 IMPURITIES

Residue on Ignition 〈281〉: NMT 0.2%

Delete the following:

Selenium 〈291〉

Sample: 200 mg

Acceptance criteria: NMT 30 ppm (USP 1-Dec-2021)

Change to read:

Organic Impurities

Standard solution A: 500 μg/mL of USP Mafenide Acetate RS in methanol

Standard solution D: 500 μg/mL of USP Mafenide Related Compound A RS in methanol

(USP 1-Dec-2021)

Standard solutions: Quantitatively dilute portions of Standard solution A with methanol to obtain Standard solution B and Standard solution C.

Similarly, quantitatively dilute portions of Standard solution D with methanol to obtain Standard solution E and Standard solution F. The compositions are shown in Table 1.

Table 1

Sample solution: 50 mg/mL of Mafenide Acetate in methanol

Identification solution: 500 μg/mL from the Sample solution in methanol

Ninhydrin solution: 300 mg of ninhydrin in 100 mL of butyl alcohol. Add 3 mL of glacial acetic acid.

Chromatographic system

(See Chromatography 〈621〉, General Procedures, Thin-Layer Chromatography.)

Mode: TLC

Adsorbent: 0.25-mm layer of chromatographic silica gel mixture

Application volume: 5 μL

Developing solvent system: Ethyl acetate, methanol, and isopropylamine (77:20:3)

Spray reagent: Ninhydrin solution

Analysis

Samples: Standard solutions, Sample solution, and Identification solution

Apply the Samples separately to the chromatographic plate. Position the plate in a chromatographic chamber, and develop the chromatograms in the Developing solvent system until the solvent front has moved about three-fourths of the length of the plate.

Remove the plate from the developing chamber, mark the solvent front, and allow the solvent to evaporate in warm, circulating air.

Examine the plate under short-wavelength UV light, and compare the intensities of any secondary spots observed in the chromatogram of the Sample solution at the R value corresponding to those of the principal spots in the chromatograms of Standard solutions D, E, and F. Spray the plate with Spray reagent, heat the plate at 105° for 5 min, and examine the plate. Compare the intensities of any secondary spots observed in the chromatogram of the Sample solution to those of the principal spots in the chromatograms of

Standard solutions A, B, and C.

Acceptance criteria: No secondary spot, observed by both visualizations, from the chromatogram of the Sample solution is larger or more intense than the principal spots obtained from Standard solution B (0.5%) and Standard solution E (0.5%). The sum of the intensities of all secondary spots obtained from the Sample solution corresponds to NMT 1.0%.

5 SPECIFIC TESTS

Melting Range or Temperature 〈741〉: Between 162° and 171°, but the range between the beginning and end of melting does not exceed 4°.

pH 〈791〉

Sample solution: 100 mg/mL

Acceptance criteria: 6.4–6.8

Water Determination 〈921〉, Method I: NMT 1.0%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers.

USP Reference Standards 〈11〉

USP Mafenide Acetate RS

USP Mafenide Related Compound A RS

4-Formylbenzenesulfonamide.

C₇H₇NO₃S 185.20