Packaging and storage—
Preserve in well-closed containers.
Identification—
Triturate a quantity of finely powdered Tablets, equivalent to about 500 mg of tolbutamide, with 50 mL of chloroform, and filter. Evaporate the clear filtrate on a steam bath to dryness: the residue so obtained responds to Identification test A under Tolbutamide.
Dissolution 
711
—
Medium: pH 7.4 phosphate buffer
(see Buffer Solutions in the section Reagents, Indicators, and Solutions); 900 mL.
Apparatus 2:
75 rpm.
Time:
30 minutes.
Procedure—
Measure the amount in solution in filtered portions of the
Dissolution Medium, suitably diluted with water, if necessary, at the wavelength of maximum absorbance at about 226 nm, with a suitable spectrophotometer, in comparison with a solution having a known concentration of
USP Tolbutamide RS. An amount of alcohol not to exceed 1% of the total volume of the Standard solution may be used to bring the Reference Standard into solution prior to dilution with
Dissolution Medium.
Tolerances—
Not less than 70% (Q) of the labeled amount of C12H18N2O3S is dissolved in 30 minutes.
Assay—
Mobile phase
, Internal standard solution, Standard preparation, and Chromatographic system—Prepare as directed in the Assay under Tolbutamide.
Assay preparation—
Weigh and finely powder not less than 10 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 150 mg of tolbutamide, to a suitable container. Add 100.0 mL of Internal standard solution and about 20 glass beads. Securely close the container, and shake vigorously by mechanical means for approximately 30 minutes. Centrifuge and use the clear supernatant.
Procedure—
Proceed as directed for
Procedure in the
Assay under
Tolbutamide. Calculate the quantity, in mg, of C
12H
18N
2O
3S in the portion of Tablets taken by the formula:
100C(RU / RS),
in which the terms are as defined therein.
