Blonanserin Dimer impurity

Blonanserin Dimer impurity is a dimeric species formed via oxidative coupling between the aromatic amine moieties of two Blonanserin monomers, resulting in a symmetrically linked biphenyl core bridged by piperazine and benzisothiazole heterocycles. The structure retains key pharmacophoric elements of the parent compound, including the 2-(4-(4-(2-hydroxyethyl)piperazin-1-yl)butyl)phenol motif, while introducing intermolecular crosslinking at the 3-position of the benzisothiazole ring. This impurity arises during API synthesis under oxidizing conditions and serves as a critical HPLC reference standard for quantifying dimerization byproducts in Blonanserin formulations.