» Tolbutamide Tablets contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of C12H18N2O3S.
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.
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.
Uniformity of dosage units 905: meet the requirements.
Mobile phase , Internal standard solution, Standard preparation, and Chromatographic systemPrepare 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 C12H18N2O3S in the portion of Tablets taken by the formula:
100C(RU / RS)in which the terms are as defined therein.
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USP32NF27 Page 3767