Assay
[NOTEProtect from light all solutions that contain nitrofurazone.
]
Triethylamine buffer, Mobile phase, Standard preparation, and Chromatographic system
Proceed as directed in the
Assay under
Nitrofurazone Ointment.
Assay preparation
Transfer an accurately measured portion of Topical Solution, equivalent to about 1 mg of nitrofurazone, to a 100-mL low actinic volumetric flask. Add 0.2 mL of dimethylformamide and about 25 mL of warm (between 40
and 50
) alcohol. Dilute with water to volume, and mix.
Procedure
Proceed as directed in the
Assay under
Nitrofurazone Ointment. Calculate the quantity, in mg, of C
6H
6N
4O
4 in the portion of Topical Solution taken by the formula:
100C(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Nitrofurazone RS in the
Standard preparation, and
rU and
rS are the nitrofurazone peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.