James E. Swauger

Toxicological Evaluation of Honey 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 increase or reduce the biological activity that results from burning tobacco. In the manufacture of cigarettes, honey is used as a casing ingredient to impart both aroma and taste. The primary objective of this document is to summarize and interpret chemical and toxicological studies that have been conducted to evaluate the potential impact of honey on the biological activity of either mainstream cigarette smoke or cigarette smoke condensate. As part of ongoing stewardship efforts, cigarettes produced with honey (5% wet weight) as an alternative to invert sugar in tobacco casing material were subjected to extensive evaluation. Principal components of this evaluation were a determination of selected mainstream smoke constituent yields, Ames assay, sister chromatid exchange assay in Chinese hamster ovary cells, a 30-wk dermal tumor promotion evaluation of cigarette smoke condensate in SENCAR mice, and a 13-wk inhalation study of cigarette smoke in Sprague-Dawley rats. Comparative analytical evaluations demonstrated that the substitution of honey for invert sugar as a casing material in cigarettes had no significant impact on mainstream smoke chemistry. In addition, in vitro and in vivo studies demonstrated that cigarettes containing tobacco cased with honey had comparable biological activity to cigarettes containing invert sugar. Collectively, these data demonstrate that the use of honey as an alternative casing material in the manufacture of cigarettes does not alter the potential toxicity of cigarette smoke condensate (CSC) or cigarette smoke; therefore the use of honey as an ingredient added to cigarette tobacco is acceptable from a toxicological perspective.

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.

Patterns of menthol cigarette use among current smokers, overall and within demographic strata, based on data from four U.S. government surveys.

The National Health and Nutrition Examination Survey, National Survey on Drug Use and Health, National Health Interview Survey and Tobacco Use Supplement to the Current Population Survey provide estimates of the proportions of U.S. smokers who currently use menthol cigarettes, overall and within demographic strata. Among adult past-month, regular and daily smokers, menthol cigarette use ranges from 26% to 30%, with statistically higher proportions of female versus male smokers (8-11 percentage points higher) currently using menthol cigarettes. Compared to adult smokers overall, statistically higher proportions of non-Hispanic Black smokers (72-79%) and statistically lower proportions of non-Hispanic White smokers (19-22%) currently use menthol cigarettes, with no differences among smokers of other race/ethnicity groups (18-20% to 28-30%, depending on the survey). Higher proportions of younger adult past-month, regular and daily smokers (aged 18-25years) currently use menthol cigarettes compared to older adult smokers (aged 26-29years and/or ⩾30years); however, differences are small in magnitude, with the vast majority of adult smokers (70-75%) who currently use menthol cigarettes being aged ⩾30years. Comparisons between youth and adult smokers are provided, although data for youth smokers are less available and provide less consistent patterns of menthol cigarette use.

Toxicological evaluation of dry ice expanded tobacco

A tiered testing strategy has been developed to evaluate the potential of tobacco processes, ingredients, or technological developments to change the biological activity resulting from burning tobacco. The strategy is based on comparative chemical and biological testing. Dry ice expanded tobacco (DIET) is an example of a common tobacco expansion process currently used in the manufacture of cigarettes to increase tobacco filling capacity. As part of the toxicological evaluation of DIET, test cigarettes containing DIET were compared with control cigarettes containing tobacco expanded with a traditional expansion agent (Freon-11, also known as trichlorofluoromethane). Testing included mainstream cigarette smoke chemistry studies, genotoxicity studies (Ames and sister chromatid exchange, SCE), a 13-week inhalation study in Sprague-Dawley rats, and a 30-week dermal tumor promotion study in SENCAR mice. Cigarettes containing DIET or Freon-11 expanded tobacco were similar in biological activity.

ANALYSIS OF POTENTIAL TRANSFER OF CONTINUOUS GLASS FILAMENT FROM ECLIPSE CIGARETTES

This study was designed to determine if a prototype of the Eclipse cigarettes, which uses a special form of continuous glass filament (CGF) as an insulator around the carbon heat source, yielded CGFs via mainstream smoke. A method was developed that used electrostatic precipitation with a greater than 99% collection efficiency of mass to capture CGFs transferred to mainstream smoke. The cigarettes were smoked using an exaggerated puffing condition that was more than twice the Federal Trade Commission (FTC) standard. The cigarettes were subjected to handling procedures that simulated commercial shipping conditions prior to smoking. CGFs were intentionally added to a series of smoke condensate samples to determine CGF recovery efficiency. The recovery efficiency was determined for a series of four internal standards added to smoke condensate. The recovery efficiency was 86% for the Eclipse 5-014 prototype. The number of CGFs in smoke condensate collected from the Eclipse 5-014 prototype was approximately 0.06 ± 0.02 CGFs per cigarette ( ± standard deviation), including the background counts of CGFs and 0.03 CGFs per cigarette, when corrected for background contributions. The number of CGFs found in smoke condensates for this prototype was not statistically distinguishable from zero or background in these experiments, which were capable of detecting transfer rates of greater than 0.2 CGFs per cigarette.This study was designed to determine if a prototype of the Eclipse cigarettes, which uses a special form of continuous glass filament (CGF) as an insulator around the carbon heat source, yielded CGFs via mainstream smoke. A method was developed that used electrostatic precipitation with a greater than 99% collection efficiency of mass to capture CGFs transferred to mainstream smoke. The cigarettes were smoked using an exaggerated puffing condition that was more than twice the Federal Trade Commission (FTC) standard. The cigarettes were subjected to handling procedures that simulated commercial shipping conditions prior to smoking. CGFs were intentionally added to a series of smoke condensate samples to determine CGF recovery efficiency. The recovery efficiency was determined for a series of four internal standards added to smoke condensate. The recovery efficiency was 86% for the Eclipse 5-014 prototype. The number of CGFs in smoke condensate collected from the Eclipse 5-014 prototype was approximately 0.06 +/- 0.02 CGFs per cigarette (+/- standard deviation), including the background counts of CGFs and 0.03 CGFs per cigarette, when corrected for background contributions. The number of CGFs found in smoke condensates for this prototype was not statistically distinguishable from zero or background in these experiments, which were capable of detecting transfer rates of greater than 0.2 CGFs per cigarette.

Primary measures of dependence among menthol compared to non-menthol cigarette smokers in the United States.

Previously published studies provide somewhat inconsistent evidence on whether menthol in cigarettes is associated with increased dependence. The National Health and Nutrition Examination Survey, National Survey on Drug Use and Health, National Health Interview Survey, and Tobacco Use Supplement to the Current Population Survey collect data on current cigarette type preference and primary measures of dependence, and thus allow examination of whether menthol smokers are more dependent than non-menthol smokers. Analyses based on combined data from multiple administrations of each of these four nationally representative surveys, using three definitions for current smokers (i.e., smoked ⩾1day, ⩾10days and daily during the past month), consistently demonstrate that menthol smokers do not report smoking more cigarettes per day than non-menthol smokers. Moreover, two of the three surveys that provide data on time to first cigarette after waking indicate no difference in urgency to smoke among menthol compared to non-menthol smokers, while the third suggests menthol smokers may experience a greater urgency to smoke; estimates from all three surveys indicate that menthol versus non-menthol smokers do not report a higher Heaviness of Smoking Index. Collectively, these findings indicate no difference in dependence among U.S. smokers who use menthol compared to non-menthol cigarettes.

Evaluating the association between menthol cigarette use and the likelihood of being a former versus current smoker.

Menthol in cigarettes has been examined for its potential to affect smoking dependence, measured primarily as number of cigarettes smoked per day and time to first cigarette after waking; the ability to quit smoking constitutes an additional measure of dependence. Successful quitting among menthol compared to non-menthol cigarette smokers is difficult to determine from the literature, due in part to the various definitions of quitting used by researchers. Nevertheless, intervention and follow-up studies of smoking cessation treatments generally indicate no differences in quitting success among menthol compared to non-menthol smokers, while cross-sectional studies suggest some differences within race/ethnicity groups. The association between menthol cigarette use and likelihood of being a former versus current smoker was examined based on data from the National Health Interview Survey and Tobacco Use Supplement to the Current Population Survey. Analyses stratified by race/ethnicity and limited to smokers who had quit at least one year prior to survey participation provided inconsistent results with regard to menthol cigarette use and quitting, both within surveys (i.e., comparing race/ethnicity groups) and between surveys (i.e., same race/ethnicity group across surveys). Evidence suggesting the existence or direction of an association between menthol in cigarettes and quitting depended on the data source.

Comparative 13-week inhalation study of cigarette smoke from cigarettes containing cast sheet tobacco.

A subchronic, nose-only inhalation study was conducted to compare the effects of mainstream smoke from a reference cigarette containing conventional reconstituted tobacco sheet at 30% of the finished blend to mainstream smoke from cigarettes containing 10% or 15% cast sheet (a specific type of reconstituted tobacco sheet) substituted for part of the conventional reconstituted tobacco. Male and female Sprague-Dawley rats were exposed for 1 h/day, 5 d/wk, for 13 wk to mainstream smoke at 0, 0.06, 0.20, or 0.80 mg wet total particulate matter per liter of air. Clinical signs, body and organ weights, clinical chemistry, hematology, carboxyhemoglobin (COHb), serum nicotine, plethysmography, gross pathology, and histopathology were determined. Exposure to cigarette smoke induced a number of changes in respiratory physiology, histopathology, and serum nicotine and COHb levels when compared to sham animals. When corresponding dose groups of reference and cast sheet mainstream smokes were compared, no biological differences were noted. At the end of the exposure period, subsets of rats from each group were maintained without smoke exposures for an additional 13 wk (recovery period). At the end of the recovery period, there were no statistically significant differences in histopathological findings observed between the reference and either cast sheet cigarette. Substitution of 10% or 15% cast sheet tobacco for conventional reconstituted tobacco sheet does not alter the inhalation toxicology of the mainstream smoke when compared to mainstream smoke from a reference cigarette containing conventional reconstituted tobacco sheet.

Toxicological evaluation of propane expanded tobacco

A tiered testing strategy has been developed to evaluate the potential for tobacco processes, ingredients, and other technological developments to increase or decrease the biological activity resulting from burning tobacco. The strategy is based on comparative chemical and biological testing. Propane expanded tobacco is an example of a processed tobacco used in the modern manufacture of cigarettes. Test cigarettes containing propane expanded tobacco were compared to control cigarettes containing tobacco expanded with a traditional expansion agent (Freon-11). The toxicological evaluation included chemistry studies using mainstream cigarette smoke (determination of selected constituent yields), in vitro studies using cigarette smoke condensate (Ames study in Salmonella typhimurium and sister chromatid exchange study in Chinese hamster ovary cells) and in vivo studies (13-week inhalation study of mainstream cigarette smoke in Sprague-Dawley rats and 30-week dermal tumor promotion study of cigarette smoke condensate in SENCAR mice). Although statistically significant differences in several smoke constituents were observed, most constituents from cigarettes containing 100% propane expanded tobacco were within market survey ranges. Furthermore, biological tests indicated that the cigarettes containing propane or Freon-11 expanded tobacco were not significantly different.

Quantative Analysis of Potential Transfer of Continuous Glass Filament From Eclipse Prototype 9-014 Cigarettes

This study was designed to determine if the Eclipse prototype 9-014 cigarettes, which use a special form of continuous glass filament (CGF) as an insulator around the carbon heat source, yield CGFs via mainstream smoke. A previously developed method (Higuchi et al., 2000) that employed electrostatic precipitation—with a greater than 99% collection efficiency of mass—was used to capture CGFs transferred to mainstream smoke. The cigarettes were smoked using an exaggerated puffing condition more than twice the Federal Trade Commission (FTC) standard. Prior to smoking, cigarettes were subjected to handling procedures that simulated commercial shipping conditions. Using a modified standard addition method, and utilizing a mixture of water and glycerol as a mock condensate, CGFs were intentionally added to a series of (mock condensate) samples to develop knowledge of CGF recovery efficiency. The linear regression model of the recovered CGFs demonstrated a recovery efficiency of 86%. This efficiency rate was applied to the number of CGFs recovered from samples of smoke condensate and associated background samples. The number of CGFs in smoke condensate collected from the Eclipse 9-014 prototype was approximately 0.32 ± 0.17 CGFs per cigarette (± standard deviation), including the background counts of CGFs, and 0.16 CGFs per cigarette when corrected for background contributions. The number of CGFs found in the smoke condensates for this prototype was statistically (p = .00031) distinguishable from zero and background in these experiments. The low number of CGFs seen in the transfer data from this prototype studied, the unique physical characteristics of the filaments ( e.g., controlled physical dimensions), and the absence of biological activity of similar glass filaments/fibers indicate that biologically significant exposure to the Eclipse smoker does not occur.This study was designed to determine if the Eclipse prototype 9-014 cigarettes, which use a special form of continuous glass filament (CGF) as an insulator around the carbon heat source, yield CGFs via mainstream smoke. A previously developed method (Higuchi et al., 2000) that employed electrostatic precipitation-with a greater than 99% collection efficiency of mass-was used to capture CGFs transferred to mainstream smoke. The cigarettes were smoked using an exaggerated puffing condition more than twice the Federal Trade Commission (FTC) standard. Prior to smoking, cigarettes were subjected to handling procedures that simulated commercial shipping conditions. Using a modified standard addition method, and utilizing a mixture of water and glycerol as a mock condensate, CGFs were intentionally added to a series of (mock condensate) samples to develop knowledge of CGF recovery efficiency. The linear regression model of the recovered CGFs demonstrated a recovery efficiency of 86%. This efficiency rate was applied to the number of CGFs recovered from samples of smoke condensate and associated background samples. The number of CGFs in smoke condensate collected from the Eclipse 9-014 prototype was approximately 0.32 +/- 0.17 CGFs per cigarette (+/- standard deviation), including the background counts of CGFs, and 0.16 CGFs per cigarette when corrected for background contributions. The number of CGFs found in the smoke condensates for this prototype was statistically (p =.00031) distinguishable from zero and background in these experiments. The low number of CGFs seen in the transfer data from this prototype studied, the unique physical characteristics of the filaments (e.g., controlled physical dimensions), and the absence of biological activity of similar glass filaments/fibers indicate that biologically significant exposure to the Eclipse smoker does not occur.