2
H-1,2,4-Benzothiadiazine-7-sulfonamide, 3,4-dihydro-6-(trifluoromethyl)-, 1,1-dioxide.
3,4-Dihydro-6-(trifluoromethyl)-2
H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide
[
135-09-1].
Packaging and storage—
Preserve in tight containers.
Identification—
Solution:
10 µg per mL.
Medium:
methanol.
pH 
791
:
between 4.5 and 7.5, in a 1 in 100 dispersion in water.
Heavy metals, Method II 231:
0.002%.
Diazotizable substances—
Standard preparation—
Transfer 10.0 mg of
USP 2,4-Disulfamyl-5-trifluoromethylaniline RS to a 50-mL volumetric flask, dissolve in and dilute with acetone to volume, and mix. Transfer 10.0 mL of this solution to a 100-mL volumetric flask, dilute with water to volume, and mix.
Test preparation—
Transfer 100 mg to a 50-mL volumetric flask, dissolve in 5 mL of acetone, dilute with water to volume, and mix.
Procedure—
Transfer 5.0 mL each of the Standard preparation, the Test preparation, and a solution of acetone in water (1 in 10) to provide the blank, to separate 25-mL volumetric flasks. To each flask add 2.0 mL of dilute hydrochloric acid (1 in 5), and immediately add 1 mL of freshly prepared sodium nitrite solution (1 in 100). Mix, and allow to stand for 5 minutes. Add 1 mL of freshly prepared ammonium sulfamate solution (1 in 10) to each flask, mix, and allow to stand for 1 minute, with frequent swirling. Add 1 mL of a freshly prepared solution of N-(1-naphthyl)ethylenediamine dihydrochloride (1 in 1000), and mix. After 1 minute, dilute with water to volume, and mix. Concomitantly, and within 5 minutes after mixing, taking care to establish the same elapsed time for each solution, determine the absorbances of the solutions in 1-cm cells at 518 nm, with a suitable spectrophotometer, using the blank to set the instrument: the absorbance of the solution from the Test preparation does not exceed that of the solution from the Standard preparation, corresponding to not more than 1.0% of diazotizable substances.
Organic volatile impurities, Method V 467:
meets the requirements.
Solvent—
Use dimethyl sulfoxide.
Assay—
Transfer about 50 mg of Hydroflumethiazide, accurately weighed, to a 100-mL volumetric flask, add methanol to volume, and mix. Transfer 2.0 mL of this solution to a second 100-mL volumetric flask, dilute with methanol to volume, and mix. Concomitantly determine the absorbances of this solution and a Standard solution of
USP Hydroflumethiazide RS in the same medium having a known concentration of about 10 µg per mL, in 1-cm cells at the wavelength of maximum absorbance at about 273 nm, with a suitable spectrophotometer, using methanol as the blank. Calculate the quantity, in mg, of C
8H
8F
3N
3O
4S
2 in the Hydroflumethiazide taken by the formula:
5C(AU / AS),
in which
C is the concentration, in µg per mL, of
USP Hydroflumethiazide RS in the Standard solution; and
AU and
AS are the absorbances of the solution of Hydroflumethiazide and the Standard solution, respectively.
;)
and 275