Medium: water; 900 mL.

Apparatus 1: 100 rpm.

Time: 120 minutes.

Procedure— Determine the amount of sennosides dissolved, employing the procedure set forth in the Assay, making any necessary volumetric adjustments.

Tolerances— Not less than 75% (Q) of the labeled amount of sennosides is dissolved in 120 minutes.

(Official January 1, 2007)

pH 7.0 phosphate buffer, Borate solution, Sodium dithionite solution, and Standard preparation— Prepare as directed in the Assay under Sennosides.

Assay preparation— Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 25 mg of sennosides, to a 25-mL volumetric flask. Add 20 mL of pH 7.0 phosphate buffer, sonicate to dissolve the sennosides, add pH 7.0 phosphate buffer to volume, and mix. Centrifuge the resulting suspension for 15 minutes at 3500 rpm. The supernatant is the Assay preparation.

Procedure— Proceed as directed for Procedure in the Assay under Sennosides. Calculate the quantity, in mg, of sennosides in the portion of Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Sennosides RS, corrected for loss on drying, in the Standard preparation, and IU and IS are the fluorescence values observed for the solutions from the Assay preparation and the Standard preparation, respectively.