Safety assessment of diammonium phosphate and urea used in the manufacture of cigarettes.

A tiered testing strategy has been employed to evaluate the potential for new ingredients, tobacco processes, and technological developments to alter the mainstream smoke or biological activity that results from burning cigarette tobacco. The foundation of this evaluation strategy is comparative testing, typically including chemical and biological assessments. In the manufacture of cigarettes, diammonium phosphate (DAP) and urea have been historically used as ingredients added to tobacco, to reconstituted tobacco sheet, and to other processed tobaccos. As part of ongoing stewardship efforts, a toxicological assessment of cigarettes with and without DAP and urea was conducted. Chemical and biological analyses were conducted for test cigarettes added 0.5% DAP and 0.2% urea in the final blend and also for those added 1.0% DAP and 0.41% urea in the final blend compared to reference cigarettes without added DAP or urea. Principal components of this evaluation included a determination of selected mainstream smoke constituent yields, an Ames assay in Salmonella typhimurium strains TA98 and TA100, a sister chromatid exchange assay in Chinese hamster ovary cells, a 13-week inhalation study of mainstream cigarette smoke in Sprague-Dawley rats, and a 30-week dermal tumor-promotion evaluation of mainstream cigarette smoke condensate in SENCAR mice. Comparative evaluations demonstrated that the addition of DAP and urea to cigarettes at up to 1% and 0.41%, respectively, does not alter the biological activity compared to reference cigarettes without DAP or urea.

Safety assessment of high fructose corn syrup (HFCS) as an ingredient added to cigarette tobacco.

A tiered testing strategy has been developed to evaluate the potential for new ingredients, tobacco processes, and technological developments to alter the biological activity that results from burning tobacco. A series of studies was initially conducted with cigarettes containing 3% high fructose corn syrup (HFCS) as an alternate tobacco casing material to corn syrup/invert sugar, including determination of selected mainstream cigarette smoke (MS) constituent yields, Ames assay, sister chromatid exchange (SCE) assay in Chinese hamster ovary (CHO) cells, a 30-week dermal tumor-promotion evaluation of cigarette smoke condensate (CSC) in SENCAR mice, and a 13-week subchronic inhalation study of MS in Sprague-Dawley rats. A second series of studies was conducted with cigarettes containing 3%, 4% and 5% HFCS including MS chemistry, Ames assay, SCE assay in CHO cells, and a neutral red cytotoxicity assays. Collectively, mainstream smoke chemistry, genotoxicity, dermal tumor-promotion, and inhalation toxicity studies demonstrated no differences between cigarettes with 3% HFCS and cigarettes with 3% corn syrup/invert sugar. Also, mainstream smoke chemistry and genotoxicity of cigarettes with 4% and 5% HFCS were not different from cigarettes with 3% HFCS. In conclusion, the addition of up to 5% HFCS to cigarette does not alter the mainstream smoke chemistry or biological activity of mainstream smoke or mainstream smoke condensate as compared to cigarettes with 3% corn syrup/invert sugar with regard to the parameters investigated and presented.