Dissolution 711
[NOTEProtect solutions from light throughout this test.
]
Medium:
0.01 N hydrochloric acid; 900 mL.
Apparatus 2:
50 rpm.
Time:
45 minutes.
Procedure
Determine the amount of C
15H
14F
3N
3O
4S
2 dissolved by employing UV absorption at the wavelength of maximum absorbance at about 271 nm on filtered portions of the solution under test, suitably diluted with water, if necessary, in comparison with a Standard solution having a known concentration of
USP Bendroflumethiazide RS in the same
Medium.
Tolerances
Not less than 75% (Q) of the labeled amount of C15H14F3N3O4S2 is dissolved in 45 minutes.
Assay
[NOTEUse low-actinic glassware for the
Assay 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.
Standard preparation
Dissolve an accurately weighed quantity of
USP Bendroflumethiazide RS in methanol, and dilute quantitatively and stepwise with methanol to obtain a solution having a known concentration of about 50 µg per mL.
Assay preparation
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 5 mg of bendroflumethiazide, to a 100-mL volumetric flask, add about 70 mL of methanol, and sonicate for 15 minutes, with occasional shaking. Dilute with methanol to volume, mix, and centrifuge a portion of the solution for 15 minutes.
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 tailing factor is not more than 2.0.
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 response of the major peak. Calculate the quantity, in mg, of C
15H
14F
3N
3O
4S
2 in the portion of Tablets taken by the formula:
0.1C(rU / rS),
in which
C is the concentration, in µg per mL, of
USP Bendroflumethiazide RS in the
Standard preparation, and
rU and
rS are the peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.