Identification—
Shake a quantity of finely powdered Tablets, equivalent to about 100 mg of chlorpropamide, with 20 mL of 1 N hydrochloric acid, and extract with 50 mL of chloroform. Filter the chloroform through chloroform-washed cotton into a suitable beaker, and evaporate the chloroform on a steam bath with the aid of a current of dry air to dryness. Dry the residue at 105
for 1 hour: the residue so obtained responds to the
Identification tests under
Chlorpropamide.
Dissolution 
711
—
Medium:
water; 900 mL.
Apparatus 2:
50 rpm.
Time:
60 minutes.
Procedure—
Determine the amount of C
10H
13ClN
2O
3S dissolved from UV absorbances at the wavelength of maximum absorbance at about 230 nm of filtered portions of the solution under test, suitably diluted with 0.1 N hydrochloric acid in comparison with a Standard solution having a known concentration of
USP Chlorpropamide RS in 0.1 N hydrochloric acid.
[NOTE—A volume of alcohol not exceeding 10% of the final volume of the Standard solution may be used to dissolve the
USP Chlorpropamide RS.
]
Tolerances—
Not less than 75% (Q) of the labeled amount of C10H13ClN2O3S is dissolved in 60 minutes.
Assay—
Mobile phase
,
Standard preparation, and
Chromatographic system—Proceed as directed in the
Assay under
Chlorpropamide.
Assay preparation—
Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 50 mg of chlorpropamide, to a 100-mL volumetric flask. Add Mobile phase to volume, mix, and filter, discarding the first 10 mL of the filtrate. Pipet 10 mL of the filtrate into a second 100-mL volumetric flask, add Mobile phase to volume, and mix.
Procedure—
Proceed as directed for
Procedure in the
Assay under
Chlorpropamide. Calculate the quantity, in mg, of C
10H
13ClN
2O
3S in the portion of Tablets taken by the formula:
1000C(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Chlorpropamide RS in the
Standard preparation; and
rU and
rS are the peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
