Identification
Finely powder a quantity of Tablets,equivalent to about 200mg of mebendazole,and mix the powder with 20mLof a mixture of chloroform and 96percent 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 10µLof this solution and 10µLof a Standard solution of
USP Mebendazole RSin a mixture of chloroform and 96percent formic acid (19:1)containing 10mg per mLto a suitable thin-layer chromatographic plate (see
Chromatography á621ñ)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 96percent 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 UVlight:the
RFvalue of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.
Dissolution á711ñ
Medium:
0.1Nhydrochloric acid containing 1.0%sodium lauryl sulfate;900mL.
Apparatus 2:
75rpm.
Time:
120minutes.
Determine the amount of C16H13N3O3dissolved by employing the following method.
Buffer solution
Dissolve 8.0g of sodium hydroxide in 2Lof water,add 3.0g of sodium lauryl sulfate,and mix;then add 20mLof phosphoric acid,and adjust with phosphoric acid to a pHof 2.5.
Mobile phase
Prepare a filtered and degassed mixture of acetonitrile and
Buffer solution(3:7).Make adjustments if necessary (see
System Suitabilityunder
Chromatography á621ñ).
Standard solution
Transfer 25mg of
USP Mebendazole RSto a 50-mLvolumetric flask,add 10.0mLof formic acid and dissolve,dilute with methanol to volume,and mix.Dilute a portion of this solution quantitatively and stepwise with
Dissolution Mediumto obtain a solution having a known concentration similar to the expected concentration in the solution under test.
Chromatographic system
(see
Chromatography á621ñ)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 1mLper 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 10µL)of filtered portions of the Standard solutionand 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 C16H13N3O3is dissolved in 120minutes.
Uniformity of dosage units á905ñ:
meet the requirements.
PROCEDURE FOR CONTENT UNIFORMITY
Standard preparation
Transfer about 20mg of
USP Mebendazole RS,accurately weighed,to a 10-mLvolumetric flask,add 4mLof 96percent formic acid,and mix to dissolve.Add isopropyl alcohol to volume,and mix.Pipet 0.5mLof this solution into a 100-mLvolumetric flask,dilute with isopropyl alcohol to volume,and mix.
Test preparation
Mix 1Tablet with 20mLof 96percent formic acid in a 100-mLvolumetric flask,and heat on a steam bath for 15minutes.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 1mg of mebendazole,to a 100-mLvolumetric flask,dilute with isopropyl alcohol to volume,and mix.
Procedure
Concomitantly determine the absorbances of the
Standard preparationand the
Test preparationin 1-cm cells at the wavelength of maximum absorbance at about 310nm,with a suitable spectrophotometer,using a 1in 500solution of 96percent formic acid in isopropyl alcohol as the blank.Calculate the quantity,in mg,of C
16H
13N
3O
3in the Tablet taken by the formula:
(TC/D)(AU/AS),
in which
Tis the labeled quantity,in mg,of mebendazole in the Tablet;
Cis the concentration,in µg per mL,of
USP Mebendazole RSin the
Standard preparation;
Dis 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
AUand
ASare the absorbances of the solutions from the
Test preparationand the
Standard preparation,respectively.
Assay
Mobile phase
Prepare a mixture of methanol and 0.05
Mmonobasic potassium phosphate (60:40),adjust with 0.1
Mphosphoric acid or 1Nsodium hydroxide to a pHof 5.5,filter,and degas.Make adjustments if necessary (see
System Suitabilityunder
Chromatography á621ñ).
Standard preparation
Transfer about 25mg of
USP Mebendazole RS,accurately weighed,to a 100-mLvolumetric flask.Add 10mLof formic acid,and heat in a water bath at 50

for 15minutes.Shake by mechanical means for 5minutes,add 90mLof methanol,and allow to cool.Dilute with methanol to volume,and mix.Transfer 5.0mLof this solution to a 25-mLvolumetric flask,dilute with
Mobile phaseto volume,mix,and filter through a filter having a porosity of 0.5µm or finer.
Assay preparation
Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 500mg of mebendazole,to a 100-mLvolumetric flask.Add 50mLof formic acid,and heat in a water bath at 50

for 15minutes.Shake by mechanical means for 1hour,dilute with water to volume,mix,and filter.Transfer 5.0mLof the filtrate to a 100-mLvolumetric flask,dilute with a solution of formic acid in methanol (1:9)to volume,and mix.Transfer 5.0mLof this solution to a 25-mLvolumetric flask,dilute with
Mobile phaseto volume,mix,and pass through a pass having a porosity of 0.5µm or finer.
Chromatographic system
(see
Chromatography á621ñ)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 L1and is maintained at about 30

.The flow rate is about 1.5mLper 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 2500theoretical plates,and the relative standard deviation for replicate injections is not more than 1%.
Procedure
Separately inject equal volumes (about 15µL)of the
Standard preparationand the
Assay preparationinto 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
Cis the concentration,in mg per mL,of
USP Mebendazole RSin the
Standard preparation;and
rUand
rSare the mebendazole peak responses obtained from the
Assay preparationand the
Standard preparation,respectively.