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163451-81-8Leflunomide EP Impurity B

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Catalogue No.:	VL1060003
CAS No.:	163451-81-8
Mol. Formula:	C12H9F3N2O2
Mol. Weight:	270.21 g/mol

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Additional information on CAS 163451-81-8

Parent drug

Leflunomide

IUPAC Name

N-(4-Trifluoromethylphenyl)-2-cyano-3-hydroxycrotonamide

Pharmacopoeial Synonyms

Leflunomide Related Compound B

Other Synonyms

Teriflunomide; 2-cyano-3-hydroxy-N-[4-(trifluoromethyl)phenyl]but-2-enamide;(Z)-2-Cyano-3-hydroxy-N-[4-(trifluoromethyl)phenyl]-2-butenamide

Smile

C/C(=C(\C#N)/C(=O)NC1=CC=C(C=C1)C(F)(F)F)/O

InChI

InChI=1S/C12H9F3N2O2/c1-7(18)10(6-16)11(19)17-9-4-2-8(3-5-9)12(13,14)15/h2-5,18H,1H3,(H,17,19)/b10-7-

Description

Leflunomide EP Impurity B, also designated Leflunomide Related Compound B and Teriflunomide, is the active metabolite and principal degradative species associated with leflunomide, corresponding to the pharmacologically relevant 2-cyano-3-hydroxy-3-methylbutanamide scaffold. CAS 163451-81-8; molecular formula C12H9F3N2O2; molecular weight 270.21 g/mol. This fluorinated anilide metabolite may arise during metabolic activation or during decomposition of the parent prodrug. Its measurement commonly requires LC-MS/MS, LC-HRMS, and stability-indicating HPLC methods to resolve it from structurally related impurities. Regulatory assessment focuses on impurity qualification, metabolite characterization, and comparison with pharmacopoeial specifications.

References

Bernhard M Kirsch, Maximilian Zeyda, Karl Stuhlmeier, Johannes Grisar, Josef S Smolen, Bruno Watschinger, Thomas M Stulnig, Walter H HÃ¶rl, Gerhard J Zlabinger, Marcus D SÃ¤emann Container: Arthritis Research & Therapy Year: 2005 Volume: 7 Issue: 3 DOI: 10.1186/ar1727 URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1174963/