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: Transfer a quantity of finely powdered Tablets, equivalent to about 10 mg of glipizide, to a glass-stoppered centrifuge tube, add 10 mL of methanol, insert a stopper into the tube, and shake. Centrifuge the mixture, and use the clear supernatant as the test solution. Separately apply, as streaks about 7 cm in length, 100 µL of the test solution and 100 µL of a Standard solution of USP Glipizide RS in methanol containing 1 mg per mL, to a thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel. Allow the streaks to dry, and develop the chromatogram in a solvent system consisting of a mixture of toluene, ethyl acetate, and 98% formic acid (5:3:2) until the solvent front has moved to within 2.5 cm of the top of the plate. Remove the plate from the developing chamber, mark the solvent front, and dry the plate at 80 for 30 minutes. Cool the plate, spray it with 0.5% sodium hypochlorite solution, and allow the plate to air-dry. Spray the plate with alcohol, air-dry, and spray with a freshly prepared mixture of 1% soluble starch solution and 1% potassium iodide solution (1:1): the RF value of the principal band obtained from the test solution corresponds to that obtained from the Standard solution.

Medium: simulated intestinal fluid TS (without pancreatin); 900 mL.

Apparatus 2: 50 rpm.

Time: 45 minutes.

Tolerances— Not less than 80% (Q) of the label claim of C21H27N5O4S is dissolved in 45 minutes.

Buffer , Mobile phase, and Standard preparation—Prepare as directed in the Assay for Glipizide.

Test preparation— Transfer 1 Tablet to an appropriate volumetric flask, add a volume of Buffer equal to one-half of the total flask volume, and shake by mechanical means for 10 minutes to allow the Tablet to disintegrate completely. Dilute with methanol to volume, and sonicate for 15 minutes to obtain a solution having a concentration of about 0.05 mg of glipizide per mL. Filter through a solvent-resistant filter.

Chromatographic system (see Chromatography 621)—Proceed as directed in the Assay for Glipizide. Chromatograph the Standard preparation, and record the peak responses as directed under Procedure: the relative standard deviation for replicate injections is not more than 1.0%.

Procedure— Separately inject equal volumes (about 20 µL) of the Standard preparation and the Test preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C21H27N5O4S in the Tablet taken by the formula: in which C is the concentration, in mg per mL, of USP Glipizide RS in the Standard preparation; V is the volume, in mL, of the Test preparation taken; and rU and rS are the peak responses obtained from the Test preparation and the Standard preparation, respectively.

Buffer and Mobile phase—Prepare as directed in the Assay for Glipizide.

Standard stock solution— Dissolve an accurately weighed quantity of USP Glipizide Related Compound A RS in methanol to obtain a solution having a known concentration of about 50 µg per mL.

Standard solution— Dissolve an accurately weighed quantity of USP Glipizide RS in methanol. To this solution add sufficient Standard stock solution, and dilute quantitatively with methanol to obtain a solution having known concentrations of about 100 µg per mL of USP Glipizide RS and about 0.5 µg per mL of USP Glipizide Related Compound A RS. Transfer 25 mL of this solution to a 50-mL volumetric flask, dilute with Buffer to volume, and mix.

Test solution— Use the Assay preparation.

Chromatographic system— Prepare as directed in the Assay for Glipizide. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the relative retention times are about 0.2 for glipizide related compound A and 1.0 for glipizide; the resolution, R, between glipizide related compound A and glipizide is not less than 1.5; and the relative standard deviation for replicate injections is not more than 5% for glipizide related compound A.

Procedure— Separately inject equal volumes (about 20 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of N-{2-[(4-aminosulfonyl)phenyl]ethyl}-5-methyl-pyrazinecarboxamide (glipizide related compound A) in the Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Glipizide Related Compound A RS in the Standard solution; and rU and rS are the peak responses of glipizide related compound A obtained from the Test solution and the Standard solution, respectively: not more than 2.0% of glipizide related compound A relative to the glipizide content, as determined in the Assay, is found.

(Official January 1, 2007)

Buffer , Mobile phase, and Standard preparation—Prepare as directed in the Assay for Glipizide.

Assay preparation— Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 5 mg of glipizide, to a 100-mL volumetric flask. Add 50 mL of methanol, and place in an ultrasonic bath for 15 minutes. Dilute with Buffer to volume, and place in the ultrasonic bath for an additional 15 minutes. Filter through a solvent-resistant filter.

Chromatographic system (see Chromatography 621)—Prepare as directed in the Assay for Glipizide. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 1.0%.

Procedure— Separately inject equal volumes (about 20 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C21H27N5O4S in the portion of Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Glipizide RS in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.