Clemastine EP Impurity A (Mixture of Diastereomers);Clemastine Impurity 3(EP Impurity B);Clemastine N-Oxide;Clemastine EP Impurity A;Clemastine Impurity 1(EP Impurity A);Clemastine Fumarate Impurity A (Mixture of Diastereomers);(1RS,2R)-2-[2-[(1R)-1-(4-Chlorophenyl)-1-phenylethoxy]ethyl]-1-methylpyrrolidine 1-oxide;ClemastineEPImpurityAFumarate