N-Methyl Trimetazidine Dihydrochloride; 1-Methyl-4-[(2,3,4-trimethoxyphenyl)methyl]piperazine Hydrochloride; N-Methyltrimetazidine Dihydrochloride,"1-Methyl-4-[(2,3,4-trimethoxyphenyl)methyl]piperazine diHydrochloride",Impurity in commercial preparation of Trimetazidine,Trimetazidine