ProMethazine IMpurity C HCl;ProMethazine EP IMpurity C;rac N-Demethyl Promethazine Hydrochloride;Promethazine EP Impurity-C (HCI);Promethazine EP Impurity C (N-Desmethyl Promethazine);Promethazine Impurity 3(Promethazine EP Impurity C);Promethazine Impurity C;Promethazine Impurity 3(EP Impurity C)