Risk assessment of tobacco involves the evaluation of toxicological ingredients and their pathway of uptake in human body. Some relevant and significant aspects regarding the conversion of tobacco constituents to cancer suspect and toxicological important substances during tobacco pyrolysis are known. Albeit some mechanisms as shown in the case of tobacco specific N-nitrosamine (TSNA) formation could have been recovered, the majority of these procedures remain obscure and rare knowledge is available concerning the conversion of tobacco constituents to activated reactive intermediates due to tobacco pyrolysis. The concentrations of nicotine and TSNA are balanced using their metabolic profile or biomarkers in urine, blood and saliva to correlate their realistic uptake. Recently the conversion of nicotine to myosmine during peroxidation reaction was demonstrated which could be similar to processes during tobacco pyrolysis. In the case of both tobacco alkaloids nicotine and myosmine problems may arise from classification of their origin. The amount of myosmine which is formed from nicotine would add to the natural given concentration in tobacco, on the other hand nicotine concentration would be diminished by this conversion. This effect would cause uncertainty of validation and biomarkers of these substances and their derived TSNA in urine, blood and saliva. As reported in the literature the filter analyses of cigarette promises a practicable methodology which would lead to preliminary insights not only in constituents of mainstream smoke (MS), in relation to environmental smoke (ETS), but also about possible candidates up taken in human organism. At the moment the effect under the concern of toxicology is not clear, but the conversion of nicotine to myosmine may be demonstrated by the analysis of cigarette filter butts from smoked cigarettes. For this reason cigarette butts were collected and the filters separated. The filters were shredded and subjected to the specific extraction procedure. The resulting extract was further cleaned up, enriched by solid-phase-extraction (SPE) procedure and analysed by high performance liquid chromatography - diode array detection (HPLC-DAD), whereupon myosmine was detected. These preliminary results clearly demonstrate that the investigation of effects from tobacco smoke in biological model systems and human being demands an accurate quantification of its most toxic relevant ingredients including the profile from conversion of nicotine to myosmine via pyrolysis. Considering the discussion of carcinogenic and toxicological risk assessment of tobacco use, the problems correlating nicotine, myosmine and TSNA from cigarette smoke requires further declaration. Acknowledgement: This work was supported by DFG grant Zwi59/2-2, and TY 81/1-2

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1603. doi:1538-7445.AM2012-1603