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Mafenide Acetate
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C7H10N2O2S·C2H4O2 246.28

Benzenesulfonamide, 4-(aminomethyl)-, monoacetate.
-Amino-p-toluenesulfonamide monoacetate [13009-99-9].
» Mafenide Acetate contains not less than 98.0 percent and not more than 102.0 percent of C7H10N2O2S·C2H4O2, calculated on the anhydrous basis.
Packaging and storage— Preserve in tight, light-resistant containers.
Identification—
A: Infrared Absorption 197K.
B: The RF value of the principal spot in the chromatogram of the Identification solution corresponds to that in the chromatogram of Standard solution A, as obtained in the test for Chromatographic purity.
Melting range 741: between 162 and 171, but the range between beginning and end of melting does not exceed 4.
pH 791: between 6.4 and 6.8, in a solution (1 in 10).
Water, Method I 921: not more than 1.0%.
Residue on ignition 281: not more than 0.2%.
Selenium 291: 0.003%, a 200-mg test specimen being used.
Heavy metals, Method II 231: 0.002%.
Chromatographic purity—
Standard solutions— Dissolve USP Mafenide Acetate RS in methanol, mix to obtain Standard solution A having a known concentration of 500 µg per mL, dissolve USP Mafenide Related Compound A RS in methanol, and mix to obtain Standard solution D having a known concentration of 500 µg per mL. [NOTE—USP Mafenide Related Compound A RS is 4-formylbenzenesulfonamide.] Quantitatively dilute portions of these solutions with methanol to obtain Standard solutions having the following compositions:
Standard
solution		 Dilution Concentration
(µg RS per mL)		 Percentage
(%, for comparison
with test specimen)
A (undiluted) 500 1.0
B 5 in 10 250 0.5
C 1 in 5 100 0.2
D (undiluted) 500 1.0
E 5 in 10 250 0.5
F 1 in 5 100 0.2
Test solution— Dissolve an accurately weighed quantity of Mafenide Acetate in methanol to obtain a solution containing 50 mg per mL.
Identification solution— Quantitatively dilute a portion of the Test solution with methanol to obtain a solution containing 500 µg per mL.
Ninhydrin solution— Dissolve 300 mg of ninhydrin in 100 mL of butyl alcohol, add 3 mL of glacial acetic acid, and mix.
Procedure— Apply separately 5 µL of the Test solution, 5 µL of the Identification solution, and 5 µL of each Standard solution to a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Position the plate in a chromatographic chamber, and develop the chromatograms in a solvent system consisting of a mixture of ethyl acetate, methanol, and isopropylamine (77:20:3) 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 Test solution at the RF value corresponding to those of the principal spots in the chromatograms of Standard solutions D, E, and F. Spray the plate with the Ninhydrin solution, heat the plate at 105 for 5 minutes, and examine the plate. Compare the intensities of any secondary spots observed in the chromatogram of the Test solution to those of the principal spots in the chromatograms of Standard solutions A, B, and C. No secondary spot, observed by both visualizations, from the chromatogram of the Test solution is larger or more intense than the principal spots obtained from Standard solution B (0.5%) and Standard solution E (0.5%), and the sum of the intensities of all secondary spots obtained from the Test solution corresponds to not more than 1.0%.
Organic volatile impurities, Method V 467: meets the requirements.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Assay— Transfer about 100 mg of Mafenide Acetate, accurately weighed, to a 50-mL volumetric flask, dissolve in about 20 mL of water, dilute with water to volume, and mix. Pipet 10 mL of this solution into a 100-mL volumetric flask containing 1 mL of 1 N hydrochloric acid, dilute with water to volume, and mix. Dissolve an accurately weighed quantity of USP Mafenide Acetate RS in 0.01 N hydrochloric acid, and dilute quantitatively and stepwise with the same solvent to obtain a Standard solution having a known concentration of about 200 µg per mL. Concomitantly determine the absorbance of both solutions in 1-cm cells at the wavelength of maximum absorbance at about 267 nm, with a suitable spectrophotometer, using 0.01 N hydrochloric acid as the blank. Calculate the quantity, in mg, of C7H10N2O2S·C2H4O2 in the portion of Mafenide Acetate taken by the formula:
0.5C(AU / AS),
in which C is the concentration, in µg per mL, of USP Mafenide Acetate RS in the Standard solution; and AU and AS are the absorbances of the solution of Mafenide Acetate and the Standard solution, respectively.
Auxiliary Information— Staff Liaison : Behnam Davani, Ph.D., MBA, Senior Scientist
Expert Committee : (MDAA05) Monograph Development-Antivirals and Antimicrobials
USP29–NF24 Page 1285
Pharmacopeial Forum : Volume No. 30(4) Page 1258
Phone Number : 1-301-816-8394