A: The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that of the Standard preparation, as obtained in the Assay.

B: Accurately weigh an amount of Tablet mass, equivalent to 10 mg of diazepam, place in a 50-mL centrifuge tube, and add 2 mL of acetone. Place the centrifuge tube in an ultrasonic bath for 5 minutes, and centrifuge. Using 100 µL of the supernatant as the test solution, 100 µL of a solution of USP Diazepam RS in acetone containing 5 mg per mL as the Standard solution, and a solvent system consisting of equal volumes of ethyl acetate and n-heptane, proceed as directed in Identification test B under Diazepam. The specified result is observed.

Medium: 0.1 N hydrochloric acid; 900 mL.

Apparatus 1: 100 rpm.

Time: 30 minutes.

Procedure— Determine the amount of C16H13ClN2O dissolved by employing UV absorption at a wavelength of about 242 nm on filtered portions of the solution under test, suitably diluted with Dissolution Medium, if necessary, in comparison with a Standard solution having a known concentration of USP Diazepam RS in the same Medium.

Tolerances— Not less than 85% (Q) of the labeled amount of C16H13ClN2O is dissolved in 30 minutes.

(Official January 1, 2007)

Mobile phase, System suitability solution, Standard preparation, and Chromatographic system— Prepare as directed in the Assay under Diazepam.

Assay preparation— Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 10 mg of diazepam, to a 100-mL volumetric flask. Add about 50 mL of methanol, sonicate for 5 minutes, shake by mechanical means for 5 minutes, dilute with methanol to volume, mix, and filter, discarding the first few mL of the filtrate.

Procedure— Proceed as directed for Procedure in the Assay under Diazepam. Calculate the quantity, in mg, of diazepam (C16H13ClN2O) in the portion of Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Diazepam RS in the Standard preparation, and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.