Identification—
B:
Ultraviolet Absorption 
197U
—
Solution:
10 µg per mL.
Medium:
methanol.
Absorptivities at 271 nm, calculated on the anhydrous basis, do not differ by more than 4.0%.
C:
Mix 5 mL of dilute hydrochloric acid (1 in 2) with 20 mg of Bendroflumethiazide, boil gently for 1 minute, and cool in an ice bath. Add in succession 0.5 mL of sodium nitrite solution (1 in 1000), 0.5 mL of ammonium sulfamate solution (1 in 200), and 0.5 mL of N-(1-naphthyl)ethylenediamine dihydrochloride solution (1 in 1000): a deep red color is produced.
Limit of 2,4-disulfamyl-5-trifluoromethylaniline—
[NOTE—Use low-actinic glassware for the
Test preparation and the
Standard preparation.]
Mobile phase—
Dissolve 5.62 g of sodium chloride and 1.97 g of anhydrous sodium acetate in 1000 mL of water in a 2-liter volumetric flask. Add 4.0 mL of glacial acetic acid and 800 mL of methanol, dilute with water to volume, mix, filter, and degas.
Test preparation—
Transfer about 25 mg of Bendroflumethiazide, accurately weighed, to a 100-mL volumetric flask, add methanol to volume, and mix. Transfer 10.0 mL of this solution to a 50-mL volumetric flask, dilute with methanol to volume, and mix.
Chromatographic system
(see
Chromatography 621)—The liquid chromatograph is equipped with a 270-nm detector and a 4.6-mm × 30-cm column that contains packing L11 maintained at a temperature of 35 ± 5
. The flow rate is about 1.5 mL per minute. Chromatograph five replicate injections of the
Standard preparation, and record the peak responses as directed for
Procedure: the relative standard deviation is not more than 3.0%, and the resolution factor between the methanol and 2,4-disulfamyl-5-trifluoromethylaniline is not less than 1.4.
Procedure—
Separately inject equal volumes (about 20 µL) of the
Standard preparation and the
Test preparation into the chromatograph, record the chromatograms, and measure the peak response of the 2,4-disulfamyl-5-trifluoromethylaniline. Calculate the percentage of 2,4-disulfamyl-5-trifluoromethylaniline in the portion of Bendroflumethiazide taken by the formula:
100(CS / CU)(rU / rS),
in which
CS is the concentration, in µg per mL, of
USP 2,4-Disulfamyl-5-trifluoromethylaniline RS in the
Standard preparation; CU is the concentration, in µg per mL, of bendroflumethiazide in the
Test preparation; and
rU and
rS are the peak responses obtained from the
Test preparation and the
Standard preparation, respectively. Not more than 1.5% of 2,4-disulfamyl-5-trifluoromethylaniline is found.
;)
