Nitrofurantoin
2,4-Imidazolidinedione, 1-[[(5-nitro-2-furanyl)methylene]amino]-. 1-[(5-Nitrofurfurylidene)amino]hydantoin ![]() ![]() ![]() Monohydrate 256.18 ![]() ![]() ![]() » Nitrofurantoin is anhydrous or contains one molecule of water of hydration. It contains not less than 98.0 percent and not more than 102.0 percent of C8H6N4O5, calculated on the anhydrous basis.
noteNitrofurantoin and solutions of it are discolored by alkali and by exposure to light, and are decomposed upon contact with metals other than stainless steel and aluminum.
Packaging and storage
Preserve in tight, light-resistant containers.
Labeling
Label it to indicate whether it is anhydrous or hydrous. Nitrofurantoin in the form of macrocrystals is so labeled. The labeling states the specific surface area and which method, specified under Specific Surface Area
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USP Reference standards
![]() ![]() USP Nitrofurantoin RS. USP Nitrofurazone RS. USP Nitrofurfural Diacetate RS.
Identification
B:
The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
Water, Method III
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Specific surface area
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Limit of nitrofurfural diacetate
In a 10-mL volumetric flask dissolve 100 mg of Nitrofurantoin in 1 mL of dimethylformamide, add acetone to volume, and mix. Apply 10 µL of this solution and 10 µL of a Standard solution of USP Nitrofurfural Diacetate RS in a 1 in 10 mixture of dimethylformamide in acetone containing 100 µg per mL to a suitable thin-layer chromatographic plate (see Chromatography
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Limit of nitrofurazone
pH 7.0 Phosphate buffer
Prepare as directed in the Assay.
Mobile phase
Prepare a filtered and degassed mixture of pH 7.0 Phosphate buffer and tetrahydrofuran (9:1).
Standard preparation
Prepare a solution of USP Nitrofurazone RS in dimethylformamide containing 5.0 µg per mL. Pipet 2 mL of this solution into a glass-stoppered flask, add 20.0 mL of water, and mix.
Test preparation
Dissolve 100 mg of Nitrofurantoin in 2.0 mL of dimethylformamide in a glass-stoppered, 25-mL flask. Add 20.0 mL of water, mix, and allow to stand for about 15 minutes to allow precipitate to form. Pass a portion of the solution through a nylon filter having a 0.45-µm porosity, and use the clear filtrate.
Chromatographic system (see Chromatography
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Procedure
Separately inject equal volumes (60 µL to 100 µL) of the Standard preparation and the Test preparation into the chromatograph, and record the chromatograms. The height of any peak appearing in the chromatogram of the Test preparation at a retention time corresponding to that of the main peak from the Standard preparation is not greater than the height of the main peak from the Standard preparation: not more than 0.01% of nitrofurazone is found.
Assay
pH 7.0 Phosphate buffer
Dissolve 6.8 g of monobasic potassium phosphate in about 500 mL of water. Add a volume of 1.0 N sodium hydroxide (about 30 mL) sufficient to adjust to a pH of 7.0, dilute with water to 1 liter, and mix.
Mobile phase
Prepare a filtered and degassed mixture of pH 7.0 Phosphate buffer and acetonitrile (88:12).
Internal standard solution
Prepare a solution containing about 1 mg of acetanilide per mL in water, and mix.
Standard preparation
Dissolve about 50 mg of USP Nitrofurantoin RS, accurately weighed, in 40.0 mL of dimethylformamide in a glass-stoppered flask, add 50.0 mL of Internal standard solution, and mix.
Assay preparation
Using about 50 mg of Nitrofurantoin, accurately weighed, proceed as directed for Standard preparation.
Chromatographic system (see Chromatography
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Procedure
Separately inject equal volumes (5 µL to 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C8H6N4O5 in the portion of Nitrofurantoin taken by the formula:
W(RU / RS)
in which W is the weight, in mg, of USP Nitrofurantoin RS in the Standard preparation; and RU and RS are the peak response ratios obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information
Please check for your question in the FAQs before contacting USP.
Chromatographic Column
USP32NF27 Page 3089
Pharmacopeial Forum: Volume No. 28(3) Page 717
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.
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