Darifenacin Open chain

Darifenacin Open Chain is a structurally distinct impurity arising from the cleavage of the quinuclidine ring system in the parent drug, resulting in a linear piperidine-based scaffold with an exposed amino functionality. This compound retains the benzoyl substituent and methoxyphenyl moiety characteristic of darifenacin but lacks the cyclic tertiary amine, presenting instead a primary amine and a terminal carboxylic acid derivative. Its open-chain configuration disrupts the parent’s conformational rigidity, altering pharmacophoric interactions. This impurity serves as a critical HPLC reference standard for quantifying degradation pathways in stability-indicating assays.