C16H13N3O3 295.29

Carbamic acid,(5-benzoyl-1H-benzimidazol-2-yl),methyl ester.
Methyl 5-benzoyl-2-benzimidazolecarbamate [31431-39-7].

Packaging and storage— Preserve in well-closed containers.

USP Reference standards á11ñ— USP Mebendazole RS.

Identification,Infrared Absorption á197Kñ.

Loss on drying á731ñ— Dry it at 105for 4hours:it loses not more than 0.5%of its weight.

Residue on ignition á281ñ: not more than 0.1%.

Heavy metals,Method IIá231ñ: 0.002%.

Chromatographic purity— Dissolve 50mg in 1.0mLof 96percent formic acid in a 10-mLvolumetric flask,add chloroform to volume,and mix.Similarly prepare a solution of USP Mebendazole RSin the same medium having a concentration of 5mg per mL.Transfer 1.0mLof this Standard solution to a 200-mLvolumetric flask,add a mixture of chloroform and 96percent formic acid (9:1)to volume,and mix (diluted Standard solution).Apply 10-µLportions of the test solution,the Standard solution,and the diluted Standard solution to 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,and no spot,other than the principal spot,in the chromatogram of the test solution is larger or more intense than the principal spot obtained from the diluted Standard solution.

Assay— Dissolve about 225mg of Mebendazole,accurately weighed,in 30mLof glacial acetic acid.Titrate with 0.1Nperchloric acid VS,determining the endpoint potentiometrically,using a calomel-glass electrode system.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 29.53mg of C16H13N3O3.

Expert Committee:(PA7)Pharmaceutical Analysis 7

USP28–NF23Page 1188

Phone Number:1-301-816-8394