Identification—
Finely powder a quantity of Tablets, equivalent to about 200 mg of mebendazole, and mix the powder with 20 mL of a mixture of chloroform and 96 percent formic acid (19:1). Warm the suspension on a water bath for a few minutes, cool, and filter through a medium-porosity, sintered-glass filter. Apply 10 µL of this solution and 10 µL of a Standard solution of
USP Mebendazole RS in a mixture of chloroform and 96 percent formic acid (19:1) containing 10 mg per mL to a suitable thin-layer chromatographic plate (see
Chromatography 
621
) coated with a 0.25-mm layer of chromatographic silica gel mixture. Allow the spots to dry, and develop the chromatogram in a solvent system consisting of a mixture of chloroform, methanol, and 96 percent formic acid (90:5:5) until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, allow the solvent to evaporate, and examine the plate under short-wavelength UV light: the
RF value of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.
Dissolution 711—
Medium:
0.1 N hydrochloric acid containing 1.0% sodium lauryl sulfate; 900 mL.
Apparatus 2:
75 rpm.
Time:
120 minutes.
Determine the amount of C16H13N3O3 dissolved by employing the following method.
Buffer solution—
Dissolve 8.0 g of sodium hydroxide in 2 L of water, add 3.0 g of sodium lauryl sulfate, and mix; then add 20 mL of phosphoric acid, and adjust with phosphoric acid to a pH of 2.5.
Mobile phase—
Prepare a filtered and degassed mixture of acetonitrile and
Buffer solution (3:7). Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard solution—
Transfer 25 mg of
USP Mebendazole RS to a 50-mL volumetric flask, add 10.0 mL of formic acid and dissolve, dilute with methanol to volume, and mix. Dilute a portion of this solution quantitatively and stepwise with
Dissolution Medium to obtain a solution having a known concentration similar to the expected concentration in the solution under test.
Chromatographic system
(see
Chromatography 621)—The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm × 3-cm column that contains packing L7. The flow rate is about 1 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 10 µL) of filtered portions of the Standard solution and the solution under test into the chromatograph, record the chromatograms, and measure the responses for the major peaks.
Tolerances—
Not less than 75% (Q) of the labeled amount of C16H13N3O3 is dissolved in 120 minutes.
Uniformity of dosage units 905:
meet the requirements.
PROCEDURE FOR CONTENT UNIFORMITY—
Standard preparation—
Transfer about 20 mg of
USP Mebendazole RS, accurately weighed, to a 10-mL volumetric flask, add 4 mL of 96 percent formic acid, and mix to dissolve. Add isopropyl alcohol to volume, and mix. Pipet 0.5 mL of this solution into a 100-mL volumetric flask, dilute with isopropyl alcohol to volume, and mix.
Test preparation—
Mix 1 Tablet with 20 mL of 96 percent formic acid in a 100-mL volumetric flask, and heat on a steam bath for 15 minutes. Cool, add isopropyl alcohol to volume, mix, and pass through a medium-porosity, sintered-glass filter. Transfer an accurately measured portion of the filtrate, equivalent to 1 mg of mebendazole, to a 100-mL volumetric flask, dilute with isopropyl alcohol to volume, and mix.
Procedure—
Concomitantly determine the absorbances of the
Standard preparation and the
Test preparation in 1-cm cells at the wavelength of maximum absorbance at about 310 nm, with a suitable spectrophotometer, using a 1 in 500 solution of 96 percent formic acid in isopropyl alcohol as the blank. Calculate the quantity, in mg, of C
16H
13N
3O
3 in the Tablet taken by the formula:
(TC / D)(AU / AS),
in which
T is the labeled quantity, in mg, of mebendazole in the Tablet;
C is the concentration, in µg per mL, of
USP Mebendazole RS in the
Standard preparation;
D is the concentration, in µg per mL, of mebendazole in the
Test preparation, based upon the labeled quantity per Tablet and the extent of dilution; and
AU and
AS are the absorbances of the solutions from the
Test preparation and the
Standard preparation, respectively.
Assay—
Mobile phase—
Prepare a mixture of methanol and 0.05
M monobasic potassium phosphate (60:40), adjust with 0.1
M phosphoric acid or 1 N sodium hydroxide to a pH of 5.5, filter, and degas. Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard preparation—
Transfer about 25 mg of
USP Mebendazole RS, accurately weighed, to a 100-mL volumetric flask. Add 10 mL of formic acid, and heat in a water bath at 50
for 15 minutes. Shake by mechanical means for 5 minutes, add 90 mL of methanol, and allow to cool. Dilute with methanol to volume, and mix. Transfer 5.0 mL of this solution to a 25-mL volumetric flask, dilute with
Mobile phase to volume, mix, and filter through a filter having a porosity of 0.5 µm or finer.
Assay preparation—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 500 mg of mebendazole, to a 100-mL volumetric flask. Add 50 mL of formic acid, and heat in a water bath at 50
for 15 minutes. Shake by mechanical means for 1 hour, dilute with water to volume, mix, and filter. Transfer 5.0 mL of the filtrate to a 100-mL volumetric flask, dilute with a solution of formic acid in methanol (1:9) to volume, and mix. Transfer 5.0 mL of this solution to a 25-mL volumetric flask, dilute with
Mobile phase to volume, mix, and pass through a filter having a porosity of 0.5 µm or finer.
Chromatographic system
(see
Chromatography 621)—The liquid chromatograph is equipped with a 247-nm detector, a precolumn that contains packing L1, and a 3.9-mm × 30-cm analytical column that contains packing L1 and is maintained at about 30
. The flow rate is about 1.5 mL per minute. Chromatograph the
Standard preparation, and record the peak responses as directed for
Procedure: the tailing factor is not more than 2.0, the column efficiency is not less than 2500 theoretical plates, and the relative standard deviation for replicate injections is not more than 1%.
Procedure—
Separately inject equal volumes (about 15 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 mebendazole (C
16H
13N
3O
3) in the portion of Tablets taken by the formula:
10,000C(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Mebendazole RS in the
Standard preparation; and
rU and
rS are the mebendazole peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
