Packaging and storage—
Preserve in well-closed, light-resistant containers.
Labeling—
The labeling indicates with which Dissolution test the product complies. Tablets intended solely for veterinary use are so labeled.
Identification—
Transfer a portion of finely powdered Tablets, equivalent to about 40 mg of furosemide, to a 100-mL volumetric flask. Add 25 mL of 0.1 N sodium hydroxide, and allow to stand for 30 minutes with occasional shaking. Dilute with water to volume, and mix. Filter the solution, discarding the first 10 mL of the filtrate, and transfer 2.0 mL to a second 100-mL volumetric flask. Add 0.02 N sodium hydroxide to volume, and mix. Proceed as directed in the
Identification test under
Furosemide Injection, beginning with “Dissolve about 10 mg of
USP Furosemide RS.”
Dissolution 
711
—
Test 1:
If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 1.
Apparatus 2:
50 rpm.
Time:
60 minutes.
Procedure—
Determine the amount of C
12H
11ClN
2O
5S dissolved from UV absorbances at the isosbestic point at 274 nm on filtered portions of the solution under test, suitably diluted with pH 5.8 phosphate buffer, in comparison with a Standard solution having a known concentration of
USP Furosemide RS in the same
Medium.
Tolerances—
Not less than 80% (Q) of the labeled amount of C12H11ClN2O5S is dissolved in 60 minutes.
Test 2:
If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 2. Tablets labeled as intended for veterinary use comply with this test.
Apparatus 2:
65 rpm.
Medium,
Time, and
Procedure—Proceed as directed under
Test 1.
Tolerances—
Not less than 80% (Q) of the labeled amount of C12H11ClN2O5S is dissolved in 60 minutes.
Limit of furosemide related compound B—
[NOTE—Protect furosemide solutions from exposure to light.
]
Mobile phase, Diluting solution, System suitability solution, and Chromatographic system—
Prepare as directed in the test for
Related compounds under
Furosemide.
Test solution—
Transfer an accurately weighed portion of finely powdered Tablets, equivalent to about 10 mg of furosemide, to a 10-mL volumetric flask, add Diluting solution to volume, and mix.
Procedure—
Separately inject equal volumes (about 20 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the peak responses. The response at 254 nm obtained for any peak observed in the chromatogram of the Test solution at a retention time corresponding to that of the Reference Standard in the Standard solution is not greater than the response at 254 nm obtained for the peak in the chromatogram of the Standard solution, corresponding to not more than 0.8% of furosemide related compound B.
Assay—
[NOTE—Protect furosemide solutions from exposure to light.
]
Mobile phase, Diluting solution, System suitability solution, and Chromatographic system—
Prepare as directed in the test for
Related compounds under
Furosemide.
Standard preparation—
Dissolve an accurately weighed quantity of
USP Furosemide RS in
Diluting solution to obtain a solution having a known concentration of about 1.0 mg per mL.
Assay preparation—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 50 mg of furosemide, to a 50-mL volumetric flask, add 30 mL of Diluting solution, and sonicate for 10 minutes. Add Diluting solution to volume, mix, and filter, discarding the first 10 mL of the filtrate.
Procedure—
Separately inject equal volumes (about 20 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the peak responses. Using the response at 254 nm, calculate the quantity, in mg, of furosemide (C
12H
11ClN
2O
5S) in the portion of Tablets taken by the formula:
50C(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Furosemide RS in the
Standard preparation; and
rU and
rS are the peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
