(Official January 1, 2007)

Mobile phase, Internal standard solution, and Standard preparation— Prepare as directed in the Assay under Triple Sulfa Vaginal Cream.

Assay preparation— Weigh and finely powder not fewer than 10 Vaginal Inserts. Transfer an accurately weighed portion of the powder, equivalent to about 144 mg of sulfacetamide, 184 mg of sulfabenzamide, and 173 mg of sulfathiazole, to a 250-mL volumetric flask. Add 10.0 mL of water, and shake for 10 minutes. Add 10.0 mL of Internal standard solution and 100 mL of acetone, and shake for 30 minutes at low speed on a mechanical shaker. Dilute with acetone to volume, mix, and allow to stand for 30 minutes. Pipet 5 mL of the clear supernatant into a 50-mL volumetric flask, and evaporate on a steam bath with the aid of a gentle stream of nitrogen to dryness. Dissolve the residue in Mobile phase, dilute with Mobile phase to volume, and mix.

Chromatographic system and Procedure— Proceed with the Vaginal Inserts as directed in the Assay under Triple Sulfa Vaginal Cream.