Packaging and storage— Preserve in well-closed containers.

USP Reference standards 11—
USP Acetohexamide RS.

Identification— Evaporate on a steam bath to dryness a 20-mL portion of the diluted chloroform solution prepared as directed in the Assay: the residue meets the requirements of Identification test A under Acetohexamide.

Dissolution 711—

Uniformity of dosage units 905: meet the requirements.

Assay— Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 500 mg of acetohexamide, to a 100-mL volumetric flask, add 60 mL of 0.1 N sodium hydroxide, and shake for 30 minutes. Dilute with water to volume, mix, and filter, discarding the first 20 mL of the filtrate. Transfer 20.0 mL of the subsequent filtrate to a 125-mL separator, add 2 mL of 3 N hydrochloric acid, and extract with four 40-mL portions of chloroform, filtering each portion through chloroform-washed paper into a 200-mL volumetric flask. Dilute with chloroform to volume, and mix. Transfer 20.0 mL of this solution to a suitable beaker, and evaporate on a steam bath to dryness. Transfer the residue, with the aid of 0.1 N sodium hydroxide, to a 100-mL volumetric flask, add 0.1 N sodium hydroxide to volume, and mix. Transfer 10.0 mL of this solution to a third 100-mL volumetric flask, dilute with water to volume, and mix. Concomitantly determine the absorbances of the solution from the Tablets and a Standard solution prepared from USP Acetohexamide RS, in the same medium, at a concentration of about 10 µg per mL, in 1-cm cells, at the wavelength of maximum absorbance at about 247 nm, with a suitable spectrophotometer, using 0.01 N sodium hydroxide as the blank. Calculate the quantity, in mg, of C15H20N2O4S in the portion of Tablets taken by the formula: in which C is the concentration, in µg per mL, of USP Acetohexamide RS in the Standard solution; and AU and AS are the absorbances of the solution from the Tablets and the Standard solution, respectively.

Topic/Question	Contact	Expert Committee
Monograph	Elena Gonikberg, Ph.D. Senior Scientist 1-301-816-8251	(MDGRE05) Monograph Development-Gastrointestinal Renal and Endocrine
Reference Standards	Lili Wang, Technical Services Scientist 1-301-816-8129 RSTech@usp.org
711	Margareth R.C. Marques, Ph.D. Senior Scientist 1-301-816-8106	(BPC05) Biopharmaceutics05

USP32–NF27 Page 1420