ISOPROMETHAZINE HYDROCHLORIDE;ProMethazine EP IMpurity B;N,N-dimethyl-2-phenothiazin-10-ylpropan-1-amine:hydrochloride;Promethazine Impurity 2(EP Impurity B);Promethazine Impurity B (Isopromethazine) HCl;PROMETHAZINE EP IMPURITY B HCL (ISOPROMETHAZINE HCL);N,N-dimethyl-2-(10H-phenothiazin-10-yl)propan-1-amine;Promethazine Impurity B