Medium: 0.05 M phosphate buffer, pH 9.5; 500 mL.

Apparatus 2: 75 rpm.

Time: 45 minutes.

Mobile phase— Prepare a filtered and degassed mixture of water and acetonitrile (1:1), and add 4.0 mL of phosphoric acid per L of solution. Make adjustments if necessary (see System Suitability under Chromatography 621).

Standard stock solution— Transfer about 15 mg of USP Glyburide RS, accurately weighed, to a 100-mL volumetric flask, dissolve in Medium with sonication until dissolved, about 25 minutes, and dilute with Medium to volume.

Standard solutions— Dilute the Standard stock solution quantitatively, and stepwise if necessary, with Medium to obtain solutions having known concentrations of 0.003 mg per mL (for Tablets labeled to contain 1.5 mg), 0.006 mg per mL (for Tablets labeled to contain 3.0 mg), 0.009 mg per mL (for Tablets labeled to contain 4.5 mg), and 0.012 mg per mL (for Tablets labeled to contain 6.0 mg).

Test solution— Pass a portion of the solution under test through a suitable 0.45-µm filter.

Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 215-nm detector and a 4.6-mm × 30-cm column that contains 10-µm packing L1. The flow rate is about 2.0 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the column efficiency is not less than 4000 theoretical plates; the tailing factor is not more than 2.0; and the relative standard deviation for replicate injections is not more than 3.0%.

Procedure— Separately inject equal volumes (about 50 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Determine the amount, in percentage, of C23H28ClN3O5S dissolved by the formula: in which rU and rS are the peak responses obtained from the Test solution and the Standard solution, respectively; CS is the concentration, in mg per mL, of the Standard solution; 500 is the volume, in mL, of Medium; 100 is the conversion factor to percentage; and LC is the Tablet label claim, in mg.

Tolerances— Not less than 70% (Q) of the labeled amount of C23H28ClN3O5S is dissolved in 45 minutes.

Medium: 0.05 M phosphate buffer, pH 8.5; 900 mL.

Apparatus 2: 50 rpm.

Time: 60 minutes.

Mobile phase— Prepare a filtered and degassed mixture of 520 mL of water containing 2.6 g of monobasic ammonium phosphate and 480 mL of acetonitrile. Make adjustments if necessary (see System Suitability under Chromatography 621).

Standard stock solution— Transfer about 67 mg of USP Glyburide RS, accurately weighed, to a 500-mL volumetric flask, dissolve in 40 mL of methanol with sonication for 5 minutes, and dilute with Medium to volume.

Standard solutions— Dilute the Standard stock solution quantitatively, and stepwise if necessary, with Medium to obtain solutions having known concentrations of 0.0017 mg per mL (for Tablets labeled to contain 1.5 mg), 0.0034 mg per mL (for Tablets labeled to contain 3 mg), 0.0047 mg per mL (for Tablets labeled to contain 4.5 mg), and 0.0067 mg per mL (for Tablets labeled to contain 6 mg).

Test solution— Pass a portion of the solution under test through a suitable 0.5-µm filter.

Chromatographic system— The liquid chromatograph is equipped with a 215-nm detector and a 4.0-mm × 25-cm column that contains 10-µm packing L7. The flow rate is about 1.5 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the tailing factor is not more than 2.0; and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 50 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Determine the amount, in percentage, of C23H28ClN3O5S dissolved by the formula: in which rU and rS are the peak responses obtained from the Test solution and the Standard solution, respectively; CS is the concentration, in mg per mL, of the Standard solution; 900 is the volume, in mL, of Medium; 100 is the conversion factor to percentage; and LC is the Tablet label claim, in mg.

Tolerances— Not less than 60% (Q) of the labeled amount of C23H28ClN3O5S is dissolved in 60 minutes.

Medium: 0.05 M phosphate buffer, pH 7.5; 900 mL.

Apparatus 2: 50 rpm.

Time: 45 minutes.

Mobile phase— Proceed as directed for the Assay.

Diluent— Prepare a mixture of acetonitrile and water (5:1).

Standard solution— Transfer about 66.6 mg of USP Glyburide RS, accurately weighed, to a 100-mL volumetric flask, and dissolve in and dilute with Diluent to volume. Transfer 10.0 mL of this solution to a 100-mL volumetric flask, and dilute with Medium to volume. Transfer 10.0 mL of this solution to a 100-mL volumetric flask, and dilute with Medium to volume.

Test solution— Pass a portion of the solution under test through a suitable 0.45-µm filter.

Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm × 25-cm column that contains packing L7. The flow rate is about 2 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 75 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Determine the amount, in percentage, of C23H28ClN3O5S dissolved by the formula: in which rU and rS are the peak responses obtained from the Test solution and the Standard solution, respectively; CS is the concentration, in mg per mL, of the Standard solution; 900 is the volume, in mL, of Medium; 100 is the conversion factor to percentage; and LC is the Tablet label claim, in mg.

Tolerances— Not less than 70% (Q) of the labeled amount of C23H28ClN3O5S is dissolved in 45 minutes.

WS (rU / rS)