5-Nitro-2-furaldehyde semicarbazone [59-87-0].
» Nitrofurazone, dried at 105 for 1 hour, contains not less than 98.0 percent and not more than 102.0 percent of C6H6N4O4.
noteAvoid exposing solutions of nitrofurazone at all times to direct sunlight, excessive heat, strong fluorescent lighting, and alkaline materials.
Packaging and storage Preserve in tight, light-resistant containers, and avoid exposure to direct sunlight and to excessive heat.
B: Ultraviolet Absorption 197U
Solution: 8 µg per mL, prepared as directed in the Assay.
Ratio: A306 / A375 does not exceed 0.25.
C: Dissolve 400 mg of potassium hydroxide in 10 mL of alcohol. Immediately before use dilute this solution with dimethylformamide to 100 mL. To 10 mL of the prepared solution add a few crystals of Nitrofurazone: a purple solution results.
pH 791 Suspend 1 g in 100 mL of water, shake for 15 minutes, allow the suspension to settle, and filter: the pH of the filtrate is between 5.0 and 7.5.
Loss on drying 731 Dry it at 105 for 1 hour: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.1%.
Ordinary impurities 466
Test solution: dimethylformamide.
Standard solution: dimethylformamide.
Application volume: 10 µL.
Eluant: a mixture of chloroform, methanol, and ammonium hydroxide (60:24:3), in a nonequilibrated chamber.
Limit of 5-nitro-2-furfuraldazine
Adsorbent: 0.5-mm layer of chromatographic silica gel.
Test solution Transfer 2.0 g to a 100-mL volumetric flask. Dissolve in 60 mL of dimethylformamide, dilute with acetone to volume, and mix.
Standard solution Transfer 50.0 mg of USP Nitrofurazone Related Compound A RS to a 100-mL volumetric flask, dissolve in and dilute with dimethylformamide to volume, and mix. [noteUSP Nitrofurazone Related Compound A RS is 5-nitro-2-furfuraldazine.] Transfer 5.0 mL of this solution to a 25-mL volumetric flask, add 10 mL of dimethylformamide, dilute with acetone to volume, and mix.
Application volume: 5 µL.
Developing solvent system: a mixture of ethyl acetate and cyclohexane (4:1).
Procedure Proceed as directed for Thin-Layer Chromatography under Chromatography 621. With a suitable densitometer, equipped with a filter having its maximum transmittance at about 254 nm, locate and scan the spot produced by the Standard solution and any spot from the Test solution having the same RF as that produced by the Standard solution: the area and intensity of any spot from the Test solution are not greater than the area and intensity produced by the spot from the Standard solution (0.5%).
Assay Transfer about 100 mg of Nitrofurazone, previously dried and accurately weighed, to a 250-mL volumetric flask, dissolve in 50 mL of dimethylformamide, dilute with water to volume, and mix. Transfer 5.0 mL of this solution to a 250-mL volumetric flask, dilute with water to volume, and mix. Concomitantly determine the absorbances of this solution and a Standard solution of USP Nitrofurazone RS in the same medium having a known concentration of about 8 µg per mL, in 1-cm cells at the wavelength of maximum absorbance at about 375 nm, with a suitable spectrophotometer, using water as the blank. Calculate the quantity, in mg, of C6H6N4O4 in the Nitrofurazone taken by the formula:
12.5C(AU / AS)in which C is the concentration, in µg per mL, of USP Nitrofurazone RS in the Standard solution, and AU and AS are the absorbances of the solution of Nitrofurazone and the Standard solution, respectively.
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USP32NF27 Page 3093Pharmacopeial Forum: Volume No. 29(6) Page 1938