(al ben' da zole).
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C12H15N3O2S 265.33

Carbamic acid, [5-(propylthio)-1H-benzimidazol-2-yl]-, methyl ester.
Methyl 5-(propylthio)-2-benzimidazolecarbamate [54965-21-8].
» Albendazole contains not less than 98.0 percent and not more than 102.0 percent of C12H15N3O2S, calculated on the dried basis.
Packaging and storage— Preserve in tight containers, and store at controlled room temperature.
USP Reference standards 11
USP Albendazole RS Click to View Structure
B: The RF value of the principal spot observed in the chromatogram of the test solution corresponds to that of the principal spot observed in the chromatogram of the Standard solution, as obtained in the test for Chromatographic purity.
Loss on drying 731 Dry it at 105 for 4 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.2%.
Chromatographic purity— Dissolve 50 mg of it in 3.0 mL of glacial acetic acid in a 5-mL volumetric flask, dilute with glacial acetic acid to volume, and mix. Similarly prepare a Standard solution containing 5 mg of USP Albendazole RS per mL. Transfer 1.0 mL of the Standard solution to a 100-mL volumetric flask, dilute with glacial acetic acid to volume, and mix (diluted Standard solution). Apply 10-µL portions of the test solution, the Standard solution, and the diluted Standard solution to a suitable thin-layer chromatographic plate (see Chromatography 621), 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 UV light: 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 250 mg of Albendazole, accurately weighed, to a suitable flask, and dissolve in 100 mL of glacial acetic acid, warming gently if necessary. Cool, and titrate with 0.1 N perchloric acid VS to a potentiometric endpoint (see Titrimetry 541. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 26.53 mg of C12H15N3O2S.
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