Carvedilol dimer HCl is a dimeric impurity formed via intermolecular coupling of two Carvedilol monomers through their terminal amine and benzyl cyanide moieties, resulting in a symmetric bis-arylamine linkage. The structure retains phenoxypropanol ether groups and cyanobenzyl substituents, with protonation of the quaternary amine by HCl. This compound arises during oxidative stress or prolonged storage of Carvedilol APIs. It serves as a critical HPLC reference standard for quantifying dimeric impurities in Carvedilol formulations.
