Olanzapine EP impurity B

Olanzapine EP Impurity B is a structurally related degradation product derived from the oxidative cleavage of the piperidine ring in the parent antipsychotic compound. It retains the thieno[2,3-b]pyridine core and 2-chlorophenyl substitution but features a truncated piperazine moiety replaced by a 4-methylpiperazin-1-yl group linked via a pyridine bridge. This impurity exhibits reduced aromatic substitution at the terminal phenyl ring compared to Olanzapine, resulting in altered lipophilicity and chromatographic behavior. It functions as a reference standard for HPLC-based quantification of oxidative degradation pathways in Olanzapine drug substances.