George M. Singer

Liposolubility as an aspect of nitrosamine carcinogenicity: quantitative correlations and qualitative observations.

Carcinogenicity data for a number of nitrosamines have been examined for possible structure-activity correlations with liposolubility by the method of Hansch. Correlations were found in two cases which support a previous mechanistic suggestion and which also suggest a possible difference between the action of nitrosopiperidines and dinitrosopiperazines in inducing olfactory carcinomas. No correlations were found for non-cyclic nitrosamines.

Induction of tumors of the esophagus in rats by nitrosomethylalkylamines

SummaryThe carcinogenic effectiveness of nitrosomethyl-n-butylamine,-n-hexylamine and-n-heptylamine was compared by administration to F344 rats at various concentrations in drinking water and by gavage in oil. Nitrosomethylbutylamine induced only tumors of the upper gastrointestinal tract, and was very toxic. Nitrosomethylhexylamine was less toxic and induced tumors of the liver and lung, as well as those the upper GI tract, when given by gavage, but only tumors of the GI tract when given in drinking water. In contrast, nitrosomethylheptylamine induced tumors of the liver and lung when given in drinking water or by gavage, but there were tumors of the esophagus only in those rats treated via the drinking water. As measured by the dose needed to produce a given carcinogenic effect, nitrosomethylheptylamine was a weaker carciogen than the other two nitrosamines, but was not inactive as has been reported previously.

Isolation of Gram Quantities of Configurational Isomers of Cyclic Nitrosamines by Preparative Liquid Chromatography

Abstract Substituted cyclic nitrosamines, e.g., 2,6-dimethyl-N-nitrosomorpholine and 3,5-dimethyl-N-nitrosopiperidine are separable into their component configurational isomers by preparative hplc. Gram quantities of the individual isomers sufficient for animal testing were obtained. The identification of contaminants in commercial 2,6-dimethylmorpholine of purported 99% is discussed.