(hye'' droe floo'' me thye' a zide).
2H-1,2,4-Benzothiadiazine-7-sulfonamide, 3,4-dihydro-6-(trifluoromethyl)-, 1,1-dioxide.
3,4-Dihydro-6-(trifluoromethyl)-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide [135-09-1].
» Hydroflumethiazide contains not less than 98.0 percent and not more than 102.0 percent of C8H8F3N3O4S2, calculated on the anhydrous basis.
Packaging and storage Preserve in tight containers.
USP Reference standards 11
USP 2,4-Disulfamyl-5-trifluoromethylaniline RS
A: Infrared Absorption 197K, previously dried over silica gel for 4 hours.
Solution: 10 µg per mL.
Melting range, Class I 741: between 270 and 275.
pH 791: between 4.5 and 7.5, in a 1 in 100 dispersion in water.
Water, Method I 921: not more than 1.0%.
Residue on ignition 281: not more than 1.0%.
Heavy metals, Method II 231: 0.002%.
Selenium 291: 0.003%.
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.
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 C8H8F3N3O4S2 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.
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USP35NF30 Page 3444