Mobile phase— Prepare as directed in the Assayfor Glyburide.

System suitability preparation— Prepare a solution of progesterone in acetonitrile having a known concentration of about 0.2mg per mL(Solution A).Transfer about 10mg of USP Glyburide RS,accurately weighed,to a suitable container,add 20.0mLof Solution A,and shake vigorously to dissolve.Add 4.0mLof water,and mix.

Standard preparation— To about 10mg of USP Glyburide RS,accurately weighed,add 20.0mLof acetonitrile,and shake vigorously to dissolve.Add 4.0mLof water,and mix.

Assay preparation— Transfer not fewer than 20Tablets to a suitable container,add water equivalent to 0.4mLof water per mg of glyburide,and swirl to disperse and wet Tablet material.Then add acetonitrile equivalent to 2.0mLof acetonitrile per mg of glyburide,and shake for 30minutes.Centrifuge a portion of the suspension so obtained,and use the clear supernatant.

Chromatographic system— Proceed as directed in the Assayfor Glyburide,except to use the System suitability preparationin place of the Standard preparation.

Procedure— Separately inject equal volumes (about 10µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the height of the major peaks.Calculate the quantity,in mg,of glyburide (C23H28ClN3O5S)in the portion of Tablets taken by the formula: in which WSis the weight,in mg,of USP Glyburide RStaken to prepare the Standard preparation;and rUand rSare the glyburide peak heights obtained from the Assay preparationand the Standard preparation,respectively.