C12H15N3O2S 265.33

Carbamic acid,[5-(propylthio)-1H-benzimidazol-2-yl]-,methyl ester.
Methyl 5-(propylthio)-2-benzimidazolecarbamate [54965-21-8].

Packaging and storage— Preserve in tight containers,and store at controlled room temperature.

USP Reference standards á11ñ— USP Albendazole RS.

Identification—

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 0.2%.

Chromatographic purity— Dissolve 50mg of it in 3.0mLof glacial acetic acid in a 5-mLvolumetric flask,dilute with glacial acetic acid to volume,and mix.Similarly prepare a Standard solution containing 5mg of USP Albendazole RSper mL.Transfer 1.0mLof the Standard solution to a 100-mLvolumetric flask,dilute with glacial acetic acid 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 Chromatographyá621ñ),coated with a 0.25-mm layer of silica gel mixture,and allow the spots to dry.Develop the chromatogram in a solvent system consisting of a mixture of chloroform,glacial acetic acid,and ether (60:10:10)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 from the plate,and examine the plate under short-wavelength UVlight:no spot,other than the principal spot,in the chromatogram of the test solution is larger or more intense than the principal spot in the chromatogram of the diluted Standard solution (0.5%).

Assay— Transfer about 250mg of Albendazole,accurately weighed,to a suitable flask,and dissolve in 100mLof glacial acetic acid,warming gently if necessary.Cool,add 1drop of oracet blue B TS,and titrate with 0.1Nperchloric acid VSto a violet-colored endpoint.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 26.53mg of C12H15N3O2S.

Expert Committee:(VET)Veterinary Drugs

USP28–NF23Page 55

Phone Number:1-301-816-8178