Relationship Between Nicotine Dependence Scores and Nicotine, Cotinine, 3′-Hydroxycotinine and Nicotine Metabolite Ratio in Chinese Male Smokers

Summary Smoking is mainly sustained by nicotine dependence (ND), which varies across ethnic groups principally due to genetic as well as environmental factors. The Fagerström Test for Nicotine Dependence (FTND) and biomarkers of tobacco exposure are two important approaches to assess ND. However, the relationship between ND and FTND of Chinese smokers has not been studied. The aim of this study was to assess the relationship between FTND scores and nicotine, cotinine, 3′-hydroxycotinine (3HC) and nicotine metabolite ratio (NMR, the concentration ratio of 3HC to cotinine) in Chinese smokers. FTND was carried out and general characteristics were collected using a self-administered smoking questionnaire with 289 smokers. Nicotine, cotinine and 3HC in urine were simultaneously determined by liquid chromatography–mass spectrometry/mass spectrometry (LC-MS/MS). The concentrations of nicotine, cotinine and 3HC in the urine of smokers with a high FTND score were higher than in the urine of those with a low FTND score. There were significant correlations between urinary biomarker and FTND scores. Except for FTND item 2 (difficulty to refrain), the other items showed significant associations with the urinary biomarkers. No relationship was found between the nicotine metabolite ratio (NMR, 3′-hydroxycotinine/cotinine) and FTND scores or general characteristics of the participants. In conclusion, biomarkers of tobacco exposure levels are significantly associated with FTND scores. However, FTND Item 2 and NMR were not found to be associated with nicotine dependence in Chinese smokers.

Inter-Laboratory Reproducibility and Interchangeability of 3R4F and 1R6F Reference Cigarettes in Mainstream Smoke Chemical Analysis and In Vitro Toxicity Assays

Summary A new reference cigarette, 1R6F, produced by the Kentucky Tobacco Research and Development Center, has been manufactured as a substitute for the 3R4F reference cigarette because of a depletion of 3R4F stock. The purpose of the current study was to investigate the interchangeability of 1R6F and 3R4F by comparing the chemical and biological characteristics of the mainstream smoke and to assess the inter-laboratory reproducibility by comparing the results obtained in the current study with a previous report. We analyzed 45 priority chemicals required by Health Canada for regulatory reporting and assessed the toxicological effects of cigarette smoke using in vitro standard toxicological assays recommended by the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) under the International Organization for Standardization (ISO) standard and intense smoking regimens. The results of the chemical analysis and standard toxicological assays showed a good inter-laboratory reproducibility for 1R6F as a reference cigarette, while there were some slight reproducible differences between 1R6F and 3R4F. In addition, we investigated the interchangeability of 1R6F with 3R4F in some additional toxicological assays that detect oxidative stress because oxidative stress is a principle endpoint used in tobacco research with next generation tobacco and nicotine delivery products (NGPs). Both 1R6F and 3R4F elicited comparable responses in the oxidative stress assays. Overall, our results showed inter-laboratory reproducibility in chemical and standard toxicological assessments of 1R6F; thus, suggesting the suitability of 1R6F as a reference cigarette. In addition, the results obtained in the oxidative stress assays provide insight into the interchangeability of 1R6F with 3R4F when used as a comparator for NGPs.

Simulation of Heat and Mass Transfer of Cut Tobacco in a Batch Rotary Dryer by Multi-Objective Optimization

Summary To simulate the drying process of cut tobacco in a batch rotary dryer, six different models of equilibrium moisture content were selected to calculate the driving force of mass transfer, and a mathematical model of heat and mass transfer was numerically solved. The multi-objective nonlinear problem of heat and mass transfer coefficients was optimized by employing a weight factor. The simulation results showed that the weight factor r was an important parameter for fitting results of moisture content and temperature. The model evaluation indices almost reached their minimal values with r at 0.1. For all the six equilibrium/classic models the fit was better for moisture content than for temperature. One model (M-Hen/C) was superior to other equilibrium/classic models and the REA (reaction engineering approach) model. This study aims for an understanding of heat and mass transfer in the tobacco drying process, and provides a theoretical framework to support the prediction of temperature and moisture in various drying situations.

Numerical Simulation of the Burning Process in a King-Size Cigarette Based on Experimentally Derived Reaction Kinetics

Summary A comprehensive two-dimensional (2D) mathematical model has been proposed to simulate the burning process of a king-size cigarette. The characteristics of this model are including: 1) the use of kinetic models for the evaporation of water, the pyrolysis of tobacco and the oxidation of char, 2) the application of mathematical relationships between the release amounts of certain products (i.e., “tar” and CO) and different reaction variables (i.e., temperatures and oxygen concentrations), 3) the introduction of mass, heat and momentum transports, 4) the consideration of filtration effects of the cigarette filter on “tar”. These characteristics were expressed in a set of coupled equations that can be solved numerically by FLUENT. The information about the char density field, temperature field, flow velocity field, “tar” and CO density fields and the filtration efficiency could be obtained from the model. This model was validated by comparing the predictions with experimental data on puff number, the temperatures at specific locations, the filtration efficiency and the yields of “tar” and CO under different puff intensities. The calculated results show a good agreement with the experimental data. The predicted puff number was 7.3, and the experimental puff number was 6.8. The standard root mean square error (NRMSE) between the experimental and the predicted temperatures at specific locations is < 18%. The predicted filtration efficiency for “tar” was 46.1%, and the experimentally determined filtration efficiency for nicotine was 44.5%. The maximum relative deviations of the yields of “tar” and CO under different puff intensities were 8.9% and 10.6%, respectively.

Robustness of HPHC Reduction for THS 2.2 Aerosol Compared with 3R4F Reference Cigarette Smoke Under High Intensity Puffing Conditions

SummaryIn the absence of standards specific for testing the reduction robustness of the levels of harmful and potentially harmful constituents (HPHCs), the aerosol from the THS 2.2, a heated tobacco product, was compared with the mainstream smoke of the 3R4F reference cigarette over a broad range of machine-smoking regimes. The average reduction and the introduced concept of threshold limits of robust reduction were derived from HPHC concentrations, in mass per tobacco-stick normalized per total puff volume, to propose an alternative for the assessment of products where nicotine-adjusted yields would be inappropriate. In addition, this study explores the influence of 3R4F reference cigarette filter ventilation, and discusses the roles of temperature and precursors in the present context of robustness of HPHC reduction. Fifty-four HPHCs were analyzed under multiple regimes in THS 2.2 aerosol and 3R4F cigarette smoke. The average reduction of HPHC concentrations compared across all regimes characterized the robustness. Threshold limits of reduction of individual HPHCs were statistically determined across all regimes. The results observed under Health Canada Intense (HCI) and more intense regimes indicated that on average the reductions in HPHCs levels investigated in THS 2.2 aerosol were more than 90% and that the majority of the 54 HPHCs investigated in THS 2.2 aerosol showed more than 90% reduction. The robustness of THS 2.2 in maintaining the levels of reduction of representative HPHCs, whatever the puffing regime, can be quantified. The mass of HPHC per tobacco-stick normalized per total puff volume is a valuable approach to compare the robustness of the performance of a product over a large range of puffing conditions. Our findings will greatly complement the assessment for robustness of current and future similar products where classical approaches would present limitations.

Statistical Analysis for Comparison of the Results Obtained by Capillary Columns and Packed Columns in the Determination of Water Yield in Smoke Condensates Analyzed in Cigarettes for the 24th Asia Collaborative Study

SummaryRecently, capillary columns have been widely used in the methodology for the determination of water yields in smoke condensate, even though ISO 10362-1:1999, “Cigarettes - Determination of water in smoke condensates – Part 1: Gas chromatographic method” specifies a packed gas chromatographic column. As a result of a systematic review in 2015, ISO/TC126 decided to revise the standard to include the use of capillary columns.The goal of this study was to confirm the comparability of water yields obtained from capillary column methodology to those yields from packed columns by the statistical analysis of yield data from the 24th Asia Collaborative Study which included 86 datasets submitted by 64 laboratories. After the exclusion of outliers by Cochran’s and Grubbs’ tests, the datasets were classified by GC column type and then mean water yields, and their repeatability and reproducibility were calculated for each type of column. No significant differences were observed in water yields between capillary and packed columns. Repeatability and reproducibility of water yields using capillary column were comparable to those using packed columns as described in ISO 10362-1:1999. From these results, it was confirmed that the capillary columns are an appropriate alternative to packed columns for the gas chromatographic procedure described in ISO 10362-1:1999.

Analysis of α-Tocopherol in Tobacco and Cigarette Smoke

Summaryα-Tocopherol, a type of vitamin E, has been known to be present in tobacco for many years. The compound is an antioxidant protecting cell membranes from oxidants. α-Tocopherol is transferred from tobacco into cigarette smoke, where it is also present. Analysis of α-tocopherol has been reported in a number of studies and in various matrices including tobacco and tobacco smoke. However, no recent publication describes a method for quantitative analysis of tocopherol in tobacco and in cigarette smoke, and many methods reported from previous studies were not published and only presented at conferences or communicated in internal company publications.The goal of this study was to quantitate α-tocopherol and, if present, α-tocopheryl acetate in tobacco and in tobacco smoke. For this analysis, an original HPLC technique was developed and is described in this report. Both UV and MS/MS (MRM mode) were used as detection procedure for the analysis. The results obtained using UV detection were in very good agreement with the results obtained using MS/MS detection. The method has been applied for the analysis of a number of tobaccos, as well as the total particulate matter (TPM) from cigarettes made with the same tobaccos. Depending on tobacco type, the levels of α-tocopherol vary in tobacco between about 200 μg/g up to about 900 μg/g (“dry weight basis”). For ISO type smoking, the levels of α-tocopherol vary in TPM between about 2 μg/mg up to slightly above 4 μg/mg of TPM. For a cigarette generating TPM of about 10 mg/cig, the α-tocopherol is between about 20 μg/cig up to about 40 μg/cig. A relatively good correlation was obtained between the level of α-tocopherol in smoke (ISO type smoking) and the level of the compound in tobacco. α-Tocopheryl acetate was absent in tobacco.

Variations of TSNA Levels in Tobaccos Upon Heating at Moderate Temperatures

SummaryTobacco-specific nitrosamines (TSNAs) including nitrosoanabasine (NAB), nitrosoanatabine (NAT), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and nitrosonornicotine (NNN) are naturally present at trace levels in tobacco. During tobacco processing, preparation of expanded tobacco, and when tobacco is used in heat-not-burn type cigarettes, the tobacco is exposed to different degrees of heat. Heating of tobacco has been reported in the literature to increase the level of TSNAs. Since the increase of TSNAs in heated tobacco is still not well understood, the present study evaluated TSNA levels in six types of tobacco as a function of moderate heat exposure. These tobaccos included: flue-cured lower stalk, flue-cured upper stalk (US), Burley lower stalk, Burley upper stalk (US), and two Oriental blends (Turkey, Greece, Bulgaria, Northern Republic Macedonia). Heating was performed in sealed glass tubes at oven temperatures of 100 °C, 150 °C, 200 °C, and 250 °C for time intervals of 2 min and 5 min. The temperatures inside the glass tubes were lower than the targets and were monitored separately as a function of glass tube heating. The study showed no meaningful differences within tobacco type (by stalk position) but showed considerable differences in the levels of TSNAs between different tobaccos, with the Burley tobaccos having the highest levels, and the Orientals the lowest. For all tobacco types, TSNAs increase to some extent when temperature increases. For 2-min heating, the increase in TSNAs is relatively small up to about 200 °C, but the levels almost double when the oven temperature increases to 250 °C. For 5-min heating, the increase in TSNAs starts at about 150 °C with a maximum at 200 °C which can reach more than double the initial TSNA level. Longer heating at 250 °C (5 min) starts to cause TSNAs decomposition and the levels are reduced.

Thermo-Oxidative Decomposition of Lovage (Levisticum officinale) and Davana (Artemisia pallens) Essential Oils under Simulated Tobacco Heating Product Conditions

SummaryThe thermo-oxidative decomposition of lovage (Levisticum officinale) and davana (Artemisia pallens) essential oils has been studied by pyrolysis-gas chromatography/mass spectrometry in 9% oxygen and 91% nitrogen atmosphere at 300 °C to simulate low-temperature tobacco heating conditions. Both lovage and davana oils contain numerous chemical substances; the main components of both oils are various oxygen-containing compounds. Isobenzofuranones are the most important constituents of lovage oil, and their relative intensity changed significantly during oxidative pyrolysis. (Z)-ligustilide underwent two kinds of decomposition reactions: an aromatization reaction resulting in the formation of butylidenephthalide and the scission of the lactone ring with the elimination of carbon dioxide or carbon monoxide. Davanone is the main component of davana oil, which did not decompose considerably during low-temperature oxidative pyrolysis. However, the relative yield of the second most intensive component, bicyclogermacrene, reduced markedly due to bond rearrangement reactions. Davana ether underwent oxidation reactions leading to the formation of various furanic compounds. The changes in the composition of both essential oils could be interpreted in terms of bond splitting, intramolecular rearrangement mechanisms and oxidation reactions of several constituents during low-temperature oxidative pyrolysis. The applied thermo-oxidative method was found to be suitable to study the stability of the essential oils and monitor the decomposition products under simulated tobacco heating conditions. In spite of the complicated composition of the essential oils, no evidence for interaction between the oil components was found. [Beitr. Tabakforsch. Int. 29 (2020) 27–43]