Albendazole

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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C₁₂H₁₅N₃O₂S         265.33 

Carbamic acid, [5-(propylthio)-1H-benzimidazol-2-yl]-, methyl ester; 

Methyl 5-(propylthio)-2-benzimidazolecarbamate CAS RN®: 54965-21-8; UNII: F4216019LN. 

1 DEFINITION 

Albendazole contains NLT 98.0% and NMT 102.0% of albendazole (C₁₂H₁₅N₃O₂S ), calculated on the dried basis.

2 IDENTIFICATION 

Change to read: 

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197M (CN 1-May-2020) 

B. The R value of the principal spot of the Sample solution corresponds to that of the principal spot of the Standard solution, as obtained in F 

the test for Organic Impurities. 

3 ASSAY 

Procedure 

Sample: 250 mg of Albendazole 

Analysis: Transfer the Sample to a suitable ask, 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. Each mL of 0.1 N perchloric acid is equivalent to 26.53 mg of C₁₂H₁₅N₃O₂S . 

Acceptance criteria: 98.0%–102.0% on the dried basis 

4 IMPURITIES 

Residue on Ignition 〈281〉: NMT 0.2% 

Organic Impurities 

Standard stock solution: 5 mg/mL of USP Albendazole RS in glacial acetic acid 

Standard solution: 0.05 mg/mL of USP Albendazole RS in glacial acetic acid from Standard stock solution 

Sample solution: 10 mg/mL in glacial acetic acid 

4.1 Chromatographic system 

(See Chromatography 〈621〉, Thin-Layer Chromatography.) 

Mode: TLC 

Adsorbant: 0.25-mm layer of silica gel mixture 

Application volume: 10 µL 

Developing solvent system: Chloroform, ether, and glacial acetic acid (60:10:10) 

4.2 Analysis

Proceed as directed for Chromatography 〈621〉, Thin-Layer Chromatography. 

Samples: Standard stock solution, Standard solution, and Sample solution 

Develop the chromatogram in the Developing solvent system 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. 

Acceptance criteria: 0.5%; no spot, other than the principal spot of the Sample solution, is larger or more intense than the principal spot of the Standard solution. 

5 SPECIFIC TESTS 

Loss on Drying 〈731〉 

Analysis: Dry at 105° for 4 h. 

Acceptance criteria: NMT 0.5% 

6 ADDITIONAL REQUIREMENTS 

Packaging and Storage: Preserve in tight containers, and store at controlled room temperature. 

USP Reference Standards 〈11〉 

USP Albendazole RS