N'-(3-Chloro-4-methylphenyl)-N,N-dimethyl-urea-13C6; 1,1-Dimethyl-3-(3-chloro-4-methylphenyl)urea-13C6; 1-(3-Chloro-4-methyl)-3,3-dimethylurea-13C6; 3-(3-Chloro-p-tolyl)-1,1-dimethylurea-13C6; Dicuran-13C6; Dicuran 500FL-13C6; Lentipur Flo-13C6; Lentipur Forte-13C6; N,N-Dimethyl-N'-(3-chloro-4-methylphenyl)urea-13C6; N-(3-Chloro-4-methylphenyl)-N',N'-dimethylurea-13C6;Syncuran-13C6; Tolurex-13C6