Assessment of tobacco heating product THP1.0. Part 8: Study to determine puffing topography, mouth level exposure and consumption among Japanese users

A framework for the systematic evaluation of a novel cigarette filter technology

Any functional change in cigarette filter design warrants a rigorous assessment to ensure comparability to existing filter functionality. This study compares the functionality of a standard CA filter with a novel cellulose-based alternative using a combination of emissions, in silico approaches, pre-clinical assessments and behavioural studies. We assess the challenges faced with a significant filtration change, the substantiation of this change and the limitations of such assessments. We explore cigarette emission chemical profiles; assess the potential toxicological impacts (in vitro and statistical modelling) of the differing chemical profiles of cigarette smoke aerosol resulting from the respective filter types; and, finally investigate the behavioural aspects associated with use of the novel filter as compared to the traditional one. The aim of the study was to establish a weight of evidence assessment framework for the comprehensive evaluation of a novel cigarette filter design as part of robust stewardship approach. The data show comparability to a standard CA filter across all assessments and highlight potential areas of investigation for future novel filter product iterations. The approach demonstrates the applicability of a comprehensive step-wise assessment framework to identify any potential increased toxicant emissions and exposures associated with using the novel filter.

Critical appraisal of interventional clinical trials assessing heated tobacco products: a systematic review

OBJECTIVE

To critically assess the methodological characteristics and quality of interventional clinical trials investigating the effects of heated tobacco products (HTPs).

DATA SOURCES

Web of Science (Core collection and MEDLINE), Scopus, MedRxiv, ClinicalTrials.gov and ICTRP trial databases and transnational HTP manufacturer online publication libraries were searched for clinical trials on HTPs published between January 2010 and April 2022.

STUDY SELECTION

Interventional clinical trials of any design, in which at least one group of adult participants used a currently marketed HTP, were selected by two reviewers with good or very good agreement.

DATA EXTRACTION

Data relating to trial characteristics and effects of intervention on primary outcomes were extracted using a predesigned form. Risk of bias was assessed using Cochrane's Risk of Bias tool v1.

DATA SYNTHESIS

40 trials were included, 29 of which were tobacco industry affiliated. Methodological characteristics, such as registration, design, setting, comparator interventions, participants, outcomes and analyses, varied between trials, though there were few significant differences between industry-affiliated and independent trials. Of the 40 trials, 33 were judged to be at high risk of bias and 6 at unclear risk of bias. Trial findings were not significantly associated with either affiliation or risk of bias.

CONCLUSIONS

The conduct and reporting of HTP interventional clinical trials were poor in many respects and limited to investigating effects of short-term exposure. These trials fall short of what is needed to determine whether HTPs are beneficial to public health, meaning they may not be a sound basis for tobacco control policy decisions.

Periodontal Health Status in Adults Exposed to Tobacco Heating System Aerosol and Cigarette Smoke vs. Non-Smokers: A Cross-Sectional Study

Tobacco heating systems (THS) are new products on the market, advertised as a less harmful alternative for smokers, in which tobacco is heated and not burned like in conventional cigarettes. This research explored the effect on periodontal tissues in contact with heating and burning tobacco residual products (smoke and tobacco).

METHODS

The sample included 66 subjects, patients of the Clinic of Dentistry in Rijeka, Croatia, aged 26-56 (median 38), 64% females. Three age- and gender-matched groups were formed (each N = 22): non-smokers, classic cigarettes smokers and THS smokers. Probing depth (PD) and clinical attachment loss (CAL) were primary research parameters.

RESULTS

Three groups differed in average PD and CAL (p ≤ 0.002), with cigarette smokers having the highest and non-smokers the lowest values (p ≤ 0.002). THS consumers generally had lower values of periodontal indices than smokers, but only CAL differed significantly (p = 0.011). Periodontal indices CAL and PD were worse in THS consumers than non-smokers, but they did not reach a level of statistical significance. Cigarette smoking was the only predictor of periodontitis (average CAL ≥ 4 mm) in logistic regression models, with an odds ratio of 4.7 (95% confidence interval 1.2-18.3; p = 0.027).

CONCLUSIONS

Exposure to nicotine-containing aerosol of THS in adults has a less harmful effect on periodontal tissues, measurable through periodontal indices (PD and CAL), compared to burning tobacco of conventional cigarettes. THS, presented as an alternative product to classic cigarettes, also has a detrimental effect on the periodontium.

Comparison of Biomarkers of Exposure in a Controlled Study of Smokers Switched from Conventional Cigarettes to Heated Tobacco Products

The heated tobacco product (HTP) heats rather than burns tobacco to release an aerosol with significantly fewer toxicants than conventional cigarette smoke and has received global attention in recent years. To investigate whether changes in biomarkers of exposure could be detected after switching from conventional cigarettes (CCs) to HTPs, 224 subjects from four cities in China participated in this study. Nine biomarkers containing tobacco-specific nitrosamines (TSNAs), volatile organic compounds (VOCs), and the biomarkers for acrolein and crotonaldehyde were determined by UPLC-MS/MS. The levels of the sum of nine biomarkers in CCs were 5.4 and 5.2 times higher than in an Original-HTP and Menthol-HTP, respectively. Among the nine biomarkers, 3HPMA and 3HMPMA accounted for the highest proportions. Switching from CCs to HTPs is good for both men and women because the changes in each biomarker in urine samples were the same in men and women. Among all the subjects, subjects aged 20-39 years had the greatest reduction in biomarker residues in urine. The findings of the present study provided useful information for the health risk research of HTPs in China.

A review of the characteristic properties of selected tobacco chemicals and their associated etiological risks

OBJECTIVES

Despite the quantum of research findings on tobacco epidemic, a review on the formation characteristics of nicotine, aldehydes and phenols, and their associated etiological risks is still limited in literature. Accordingly, knowledge on the chemical properties and free radical formation during tobacco burning is an important subject towards unravelling the relationship between smoking behaviour and disease. This review investigates how scientific efforts have been advanced towards understanding the release of molecular products from the thermal degradation of tobacco, and harm reduction strategies among cigarette smokers in general. The mechanistic characteristics of nicotine and selected aldehydes are critically examined in this review. For the purpose of this work, articles published during the period 2004-2021 and archived in PubMed, Google Scholar, Medley, Cochrane, and Web of Science were used. The articles were selected based on the health impacts of cigarette smoking, tobacco burning kinetics, tobacco cessation and tobacco as a precursor for emerging diseases such as Covid-19.

CONTENT

The toxicity of cigarette smoke is directly correlated with its chemical composition derived from the pyrolysis of tobacco stem and leaves. Most of the harmful toxic substances are generated by pyrolysis during smoking and depends on pyrolysis conditions. Detailed studies have been conducted on the kinetics of nicotine by use of robust theoretical models in order to determine the rate constants of reactions in nicotine and those of nicotine dissociation via C-C and C-N scission, yielding pyridinyl and methyl radicals, respectively. Research has suggested that acetaldehyde enhances the effect of nicotine, which in turn reinforces addiction characteristics whereas acrolein and crotonaldehyde are ciliatoxic, and can inhibit lung clearance. On the other hand, phenol affects liver enzymes, lungs, kidneys, and the cardiovascular system while m-cresol attacks the nervous system.

SUMMARY AND OUTLOOK

The characteristics of chemical release during tobacco burning are very important in the tobacco industry and the cigarette smoking community. Understanding individual chemical formation from cigarette smoking will provide the necessary information needed to formulate sound tobacco reform policies from a chemical standpoint. Nonetheless, intense research is needed in this field in order to prescribe possible measures to deter cigarette smoking addiction and ameliorate the grave miseries bedevilling the tobacco smoking community.

Electronic Cigarette Nicotine Flux, Nicotine Yield, and Particulate Matter Emissions: Impact of Device and Liquid Heterogeneity

INTRODUCTION

Electronic cigarettes (ECIGs) heat a nicotine-containing liquid to produce an inhalable aerosol. ECIG power (wattage) and liquid nicotine concentration are two factors that predict nicotine emission rate ("flux"). These factors can vary greatly across devices and users.

AIMS AND METHODS

The purpose of this study was to examine ECIG device and liquid heterogeneity in "real world" settings and the association with predicted nicotine flux, nicotine yield, and total particulate matter (TPM) emissions. Past 30-day ECIG users (n = 84; mean age = 23.8 years [SD = 9.6]) reported device and liquid characteristics. Device power was measured via multimeter, device display screens, or obtained via labeling. Liquid nicotine concentration was obtained via labeling or through chemical analysis. Predicted nicotine flux, nicotine yield, and TPM associated with 10 4-second puffs were calculated for participants' primary devices.

RESULTS

Participants' primary devices were box mods (42.9%), disposable vapes (20.2%), and pod mods (36.9%). Most participants (65.5%) reported not knowing their primary device wattage. Rebuildable/box mods had the greatest power range (11.1-120.0 W); pod mod power also varied considerably (4.1-21.7 W). Unlike device wattage, most participants (95.2%) reported knowing their liquid nicotine concentration, which ranged from 3.0 to 86.9 mg/ml (M = 36.0, SD = 29.3). Predicted nicotine flux varied greatly across products (range =12.0-160.1 μg/s, M = 85.6 μg/s, SD = 34.3). Box mods had the greatest variability in wattage and predicted nicotine flux, nicotine yield, and TPM yield.

CONCLUSIONS

ECIG device and liquid heterogeneity influence nicotine and other toxicant emissions. Better measurement of ECIG device and liquid characteristics is needed to understand nicotine and toxicant emissions and to inform regulatory policy.

IMPLICATIONS

ECIG device and liquid heterogeneity cause great variability in nicotine flux and toxicants emitted. These data demonstrate the need to examine device and liquid characteristics to develop empirically informed, health-promoting regulatory policies. Policies may include setting product standards such that ECIG products cannot (1) have nicotine fluxes much greater than that of a cigarette to decrease the risk of dependence, (2) have nicotine fluxes that are very low and thus would have minimal appeal to cigarette smokers and may serve as starter products for youth or nontobacco users, and (3) emit large amounts of particulate matter and other toxicants.

Twenty-eight day repeated exposure of human 3D bronchial epithelial model to heated tobacco aerosols indicates decreased toxicological responses compared to cigarette smoke

Tobacco harm reduction (THR) involves providing adult smokers with potentially reduced harm modes of nicotine delivery as alternatives to smoking combustible cigarettes. Heated tobacco products (HTPs) form a category with THR potential due to their ability to deliver nicotine and flavours through heating, not burning, tobacco. By eliminating burning, heated tobacco does not produce smoke but an aerosol which contains fewer and lower levels of harmful chemicals compared to cigarette smoke. In this study we assessed the in vitro toxicological profiles of two prototype HTPs' aerosols compared to the 1R6F reference cigarette using the 3D human (bronchial) MucilAir™ model. To increase consumer relevance, whole aerosol/smoke exposures were delivered repeatedly across a 28 day period (16, 32, or 48 puffs per exposure). Cytotoxicity (LDH secretion), histology (Alcian Blue/H&E; Muc5AC; FoxJ1 staining), cilia active area and beat frequency and inflammatory marker (IL-6; IL-8; MMP-1; MMP-3; MMP-9; TNFα) levels were assessed. Diluted 1R6F smoke consistently induced greater and earlier effects compared to the prototype HTP aerosols across the endpoints, and in a puff dependent manner. Although some significant changes across the endpoints were induced by exposure to the HTPs, these were substantially less pronounced and less frequently observed, with apparent adaptive responses occurring over the experimental period. Furthermore, these differences between the two product categories were observed at a greater dilution (and generally lower nicotine delivery range) for 1R6F (1R6F smoke diluted 1/14, HTP aerosols diluted 1/2, with air). Overall, the findings demonstrate the THR potential of the prototype HTPs through demonstrated substantial reductions in toxicological outcomes in in vitro 3D human lung models.

Evaluation of behavioural, chemical, toxicological and clinical studies of a tobacco heated product glo™ and the potential for bridging from a foundational dataset to new product iterations

Background

Tobacco Heating Products (THPs) are tobacco products that heat rather than burn tobacco with temperatures less than 350 °C. Because of this operating principle, they produce substantially fewer and lower levels of tobacco smoke toxicants than combustible cigarette smoke produced when tobacco is burnt, which occurs at much higher temperatures of around 900 °C. This paper analyses data on a THP, glo™, and assesses whether its use would result in reduced health risks compared to the health risks of smoking cigarettes. It also looks at the possibility of bridging datasets across the different variants of the glo™ product.

Methods

The approach is to consider whether datasets from behavioural, chemical, toxicological and clinical studies provide consistent findings of reductions in toxicant exposure with glo™ use by subjects who switch completely from smoking cigarettes to using glo™ and whether these reductions are similar to those who stop smoking cigarettes without switching to glo™ or any other tobacco or nicotine product. We also examine the similarities and differences of different versions of the glo™ product and benchmark it against a THP from another manufacturer.

Results

The studies indicate that the use of the glo™ results in substantial and prolonged reductions in toxicant exposure for smokers who switch to glo™ completely. A long-term clinical study shows substantial reductions in toxicant exposure over a period of time, similar to reduction of some biomarkers of exposure found following smoking cessation without switching to glo™ or any other tobacco product, and biomarkers of potential harm trending in a favourable manner for both groups that switch to glo™ and that quit all tobacco and nicotine use. Data suggests that all iterations of glo™ result in substantial reductions in toxicant exposure compared to smoking cigarettes and that bridging across datasets is feasible.

Conclusions

Given the accumulated scientific data summarised in this paper, and particularly the findings from a long-term clinical study, the data demonstrate that glo™ is a reduced exposure product compared to combustible cigarettes and is reasonably deemed to reduce the risk of smoking-related diseases and supports the conclusion that smokers who would have otherwise continued to smoke and instead switch entirely to THP glo™ use, will reduce their relative risk of developing smoking-related diseases as compared to continued smoking. The extent of reduction in risk compared to continuing to smoke is likely to vary by smoking-related disease and by an individuals' smoking history, other risk factors and an individual's susceptibility to disease. Use of the THP will present some level of increased health risk as compared to cessation of tobacco and nicotine products and will cause dependence. As long as the principles of heat-not-burn are maintained, THP use will result in substantially reduced exposure to smoke toxicants as compared to continued conventional cigarette smoking. It is possible to use bridging or read across to apply these conclusions to new iterations of the glo™ product, extending the utility and validity of the evidence generated through study of prior iterations.

Analysis of waterpipe aerosol constituents in accordance with the ISO standard 22486

•

ISO 22486 to be complemented with real conditions for the evaluation of waterpipe.

•

Charcoal is the main contributor to CO and BaP in waterpipe aerosols.

•

Correlation between sugars content in tobaccos and formaldehyde yields in aerosols.

This study analyzed commercial waterpipe tobacco products in accordance with the newly developed ISO 22486 as well as with commercial waterpipes and charcoals using the ISO 22486 puffing regime for comparison. The aerosols from these products were analyzed for their nicotine, humectant, tobacco specific nitrosamine, carbonyl, benzo[a]pyrene, and metal yields. Significant differences were observed among the waterpipe tobacco products when analyzed in accordance with the ISO standard 22486 and with different commercial waterpipes and charcoals. The concentrations of CO and benzo[a]pyrene observed in the consumers’ configuration using the ISO 22486 puffing regime (with lit charcoal) were higher than those obtained with the ISO standard using electrical heating, with the yields for carbonyl compounds being lower or higher. The use of the recently published ISO standard for generating water pipe tobacco aerosols should be complemented with analysis by using the consumers’ configuration. The necessity for this was demonstrated by the differences in CO and benzo[a]pyrene yields in the present work. It appears that the temperature (280°C) selected for electrical heating of waterpipe tobacco products in ISO 22486 is somewhat lower than that obtained with commercial charcoals, resulting in a generally lower yield of nicotine and total collected matter. In addition, there is a need to evaluate the contribution of commercial charcoals to the concentration of constituents in waterpipe aerosols. This is particularly true for compounds resulting from charcoal combustion, such as CO and benzo[a]pyrene.

The genotoxicological assessment of a tobacco heating product relative to cigarette smoke using the in vitro micronucleus assay

In vitro studies have supported the toxicological evaluation of chemicals and complex mixtures including cigarette smoke and novel tobacco and nicotine products which include tobacco heating products (THP). This new environment requires faster testing, higher throughput and appropriate in vitro studies, to support product innovation and development. In this study, total particulate matter (TPM) from a commercially available THP and a reference cigarette (3R4F) were assessed up to 500 μg/mL using two in vitro micronucleus techniques. V79 and TK6 cells were assessed using conventional OECD 487 manual scoring techniques, whereas, CHO cells were assessed using contemporary, automated high content screening approaches (Cellomics ArrayScan® VTI). V79 cells gave the most consistent response with all three treatment conditions producing a clear positive genotoxic response. Human TK6 cells only produced dose-dependent response, indicative of a weak-positive response. CHO cells demonstrated a positive response with TPM using long (24 h) -S9 conditions. All three cell lines equally demonstrated a negative response with THP TPM up to 500 μg/mL. In conclusion, THP TPM did not increase micronuclei formation above control levels even at doses far exceeding that tested with reference cigarette smoke, in most cases up to 10x the dose delivered compared to that of cigarette smoke. This study supports the growing belief that THPs are less risky than conventional cigarettes and that 21st century screening techniques can be employed to support product design and decision making, as a potential 1st screen prior to more traditional assessments.

State-of-the-art methods and devices for the generation, exposure, and collection of aerosols from heat-not-burn tobacco products

Tobacco harm reduction is increasingly recognized as a promising approach to accelerate the decline in smoking prevalence and smoking-related population harm. Potential modified risk tobacco products (MRTPs) must undergo a rigorous premarket toxicological risk assessment. The ability to reproducibly generate, collect, and use aerosols is critical for the characterization, and preclinical assessment of aerosol-based candidate MRTPs (cMRTPs), such as noncombusted cigarettes, also referred to as heated tobacco products, tobacco heating products, or heat-not-burn (HNB) tobacco products. HNB tobacco products generate a nicotine-containing aerosol by heating tobacco instead of burning it. The aerosols generated by HNB products are qualitatively and quantitatively highly different from cigarette smoke (CS). This constitutes technical and experimental challenges comparing the toxicity of HNB aerosols with CS. The methods and experimental setups that have been developed for the study of CS cannot be directly transposed to the study of HNB aerosols. Significant research efforts are dedicated to the development, characterization, and validation of experimental setups and methods suitable for HNB aerosols. They are described in this review, with a particular focus on the Tobacco Heating System version 2.2. This is intended to support further studies, the objective evaluation and verification of existing evidence, and the development of scientifically substantiated HNB MRTPs.

A cross-category puffing topography, mouth level exposure and consumption study among Italian users of tobacco and nicotine products

Actual use studies play a key part in evaluating the reduced risk potential of tobacco and nicotine products. This study was undertaken to determine the puffing topography, mouth level exposure (MLE) and average daily consumption (ADC) relating to two commercially available tobacco heating products (THPs) and a prototype electronic cigarette (or e-cigarette) among Italian non-mentholated 7 mg ISO tar cigarette smokers. The study was conducted in Milan, Italy, with three groups of approximately 50 participants. Groups 1 and 3 included adult smokers of 7 mg ISO tar tobacco cigarettes, and Group 2 consisted of both solus vapers and dual users of vapour and tobacco products. Amongst smokers, e-cigarette mean puff volumes (41.6 mL vs 41.3 mL) and mean puff durations (1.4 s vs 1.5 s) were similar to that of the cigarette, although the average usage session was significantly longer (1064.8 s vs 289.5 s) with a higher total number of puffs (58.6 vs 17.3), however this may be attributable to differences in product operation. There were no significant differences across puffing topography measurements observed between smokers (Group 1) and regular vapers/dual users (Group 2) when using the e-cigarette. As consistent with previous research, users took, on average, larger mean puff volumes when using a THP compared to the reference cigarette (C651), although puff numbers and puff durations remained similar. The average interval between puffs was considerably shorter for THP1.0(T) compared to THS2.4(T) (11.0 s vs 17.1 s). MLE to nicotine-free dry particulate matter and nicotine was significantly reduced for THP1.0(T) and THS2.4(T) compared to the tobacco cigarette (C651). MLE to nicotine was also significantly reduced for the e-cigarette (IS1.0(T)) compared to C651. The average daily consumption (ADC) of cigarettes by groups 1 and 3 were higher than the respective ADCs of both THP consumables. There were no significant differences in ADC when comparing the same product between different groups. Differences seen between sensory scores for each of the product categories may be attributed to fundamental differences in design and mode of operation resulting in very different characteristics of the aerosol generated.

In vitro mutagenicity of gas-vapour phase extracts from flavoured and unflavoured heated tobacco products

The in vitro mutagenic and genotoxic potential of Heated Tobacco Products (HTPs) has already been studied with the particulate phase and reported previously. This study has been designed to complement the in vitro assessment of the HTP and to determine whether the inclusion of potential flavourings would alter the in vitro response by testing the other phase of the aerosol, the gas-vapour phase (GVP). Both flavoured and unflavoured Neostik GVP samples did not show any sign of mutagenic activity in the Ames test but induced a mutagenic response in the mouse lymphoma assay (MLA), however, these responses were significantly less than those of the reference cigarette, 3R4F. The results demonstrated that GVP emissions of this HTP did not induce either new qualitative or quantitative mutagenic hazards compared to 3R4F, as assessed by the Ames test (no new responsive strains) and MLA (a lower mutagenic response), respectively. A statistical comparative analysis of the responses showed that the addition of flavourings that may thermally decompose under the conditions of use did not add to the in vitro baseline responses of the unflavoured Neostik.

Heated Tobacco Products: A Review of Current Knowledge and Initial Assessments

The health risks of tobacco smoking have been documented in numerous studies and smoking rates have declined in developed countries over the last 50 years. Today, we know that cigarette smoking is the major cause of preventable deaths due to tobacco smoke induced diseases. As a consequence of an increased awareness of smoking-related health risks, heated tobacco products (HTPs) are marketed as reduced toxicant alternatives to conventional tobacco products. Manufacturers claim that levels of toxicants and hazardous compounds are significantly reduced, implying that inhalation of the modified aerosol is less harmful compared to conventional cigarettes. In this manuscript, previous assessments of HTPs are briefly summarized, including a short discussion on challenges with the adaption of standard analytical methods used for tobacco smoke. The reliability of analytical data is important for risk assessment approaches that are based on reduced toxicant exposure. In order to assess a putative reduction of health risks, an integrated study design is required that should include clinical studies and epidemiology data. One manufacturer applied for a classification as a Modified Risk Tobacco Product (MRTP) in the United States, based on extensive toxicological studies that have also been published. However, data are not yet sufficient for a reliable assessment or recognition of putatively reduced health risks. Challenges regarding a classification in Europe are also discussed briefly in this review.

Heat-not-burn tobacco products: a systematic literature review

OBJECTIVE

To review peer-reviewed evidence on heat-not-burn tobacco products (HnB), their secondhand emissions and use by humans; to identify differences between independent and industry-funded studies.

DATA SOURCES

Medline, Embase, PsycINFO, ProQuest, Scopus and Web of Science databases were searched up to 6 November 2017 for studies on HnB published after December 2009; reference lists were screened and other researchers contacted, yielding 637 records.

STUDY SELECTION

Thirty-one publications on HnB secondhand emissions (n=16) or use by humans (n=15) were selected by two reviewers with excellent agreement (k=0.75).

DATA EXTRACTION

Data on authors' affiliations, HnB products, secondhand emissions and human exposure were extracted by one reviewer. Two reviewers assessed the quality of experimental HnB studies using the Effective Public Health Practice Project tool.

DATA SYNTHESIS

Twenty out of 31 studies were affiliated with tobacco industry. Studies on secondhand emissions varied by methodology, products and comparators. Compared with cigarettes, HnB delivered up to 83% of nicotine and reduced levels of harmful and potentially harmful toxicants by at least 62% and particulate matter by at least 75%. Experimental HnB use studies were limited to one product, reductions of human exposure to toxicants varied between 42% and 96%. HnB use suppressed urges to smoke, but participants rated HnB less satisfying than cigarettes. While limited by methodological heterogeneity, findings were largely similar for independent and industry-funded studies.

CONCLUSIONS

Studies on HnB secondhand emissions and human use were heterogeneous and largely affiliated with the manufacturers. HnB exposed users and bystanders to toxicants, although at substantially lower levels than cigarettes.

Changes in Biomarkers of Exposure on Switching From a Conventional Cigarette to Tobacco Heating Products: A Randomized, Controlled Study in Healthy Japanese Subjects

BACKGROUND

Smoking is a leading cause of numerous human disorders including pulmonary disease, cardiovascular disease, and cancer. Disease development is primarily caused by exposure to cigarette smoke constituents, many of which are known toxicants. Switching smokers to modified risk tobacco products (MRTPs) has been suggested as a potential means to reduce the risks of tobacco use, by reducing such exposure.

METHODS

This randomized, controlled study investigated whether biomarkers of toxicant exposure (BoE) were reduced when smokers switched from smoking combustible cigarettes to using a novel (glo™/THP1.0) or in-market comparator (iQOS/THS) tobacco heating product (THP). One hundred eighty Japanese smokers smoked combustible cigarettes during a 2-day baseline period, followed by randomization to either continue smoking cigarettes, switch to using mentholated or non-mentholated variants of glo™, switch to using a non-mentholated variant of iQOS, or quit nicotine and tobacco product use completely for 5 days. Baseline and post-randomization 24-h urine samples were collected for BoE analysis. Carbon monoxide was measured daily in exhaled breath (eCO).

RESULTS

On day 5 after switching, urinary BoE (excluding for nicotine) and eCO levels were significantly (p < .05) reduced by medians between 20.9% and 92.1% compared with baseline in all groups either using glo™ or iQOS or quitting tobacco use. Between-group comparisons revealed that the reductions in the glo™ groups were similar (p > .05) to quitting in many cases.

CONCLUSIONS

glo™ or iQOS use for 5 days reduced exposure to smoke toxicants in a manner comparable to quitting tobacco use. THPs are reduced exposure tobacco products with the potential to be MRTPs.

IMPLICATIONS

This clinical study demonstrates that when smokers switched from smoking combustible cigarettes to using tobacco heating products their exposure to smoke toxicants was significantly decreased. In many cases, this was to the same extent as that seen when they quit smoking completely. This may indicate that these products have the potential to be reduced exposure and/or reduced risk tobacco products when used by smokers whose cigarette consumption is displaced completely.

CLINICAL TRIAL REGISTRATIONS

ISRCTN14301360 and UMIN000024988.

Free-Base Nicotine Is Nearly Absent in Aerosol from IQOS Heat-Not-Burn Devices, As Determined by 1H NMR Spectroscopy

Heat-not-burn products, eg, I quit ordinary smoking (IQOS), are becoming popular alternative tobacco products. The nicotine aerosol protonation state has addiction implications due to differences in absorption kinetics and harshness. Nicotine free-base fraction (α_fb) ranges from 0 to 1. Herein, we report α_fb for IQOS aerosols by exchange-averaged ¹H NMR chemical shifts of the nicotine methyl protons in bulk aerosol and verified by headspace-solid phase microextraction-gas chromatography-mass spectrometry. The α_fb ≈ 0 for products tested; likely a result of proton transfer from acetic acid and/or other additives in the largely aqueous aerosol. Others reported higher α_fb for these products, however, their methods were subject to error due to solvent perturbation.

Investigation of menthol content and transfer rates in cigarettes and Tobacco Heating System 2.2

Menthol cigarettes account for a significant market share in many countries. However, little recent data exists on menthol levels in cigarettes and in mainstream smoke, limited to some markets or specific cigarette designs, such as cigarettes containing capsules filled with flavoring liquids. Samples of mentholated cigarettes bought worldwide with a variety of cigarette designs were analyzed for menthol content in cigarettes and in cigarette mainstream smoke with two analytical machine smoking regimes. A wide range of menthol content in cigarettes, from 1 to 22 mg/cigarette, was observed. The transfer of menthol to the cigarette mainstream smoke was generally slightly higher than the transfer of nicotine, with a range of 17%-40% using an intense smoking regime and 1%-17% using the ISO smoking regime. For the Tobacco Heating System (THS) 2.2, the menthol content was 12.8 mg/stick, and the transfer of menthol into the aerosol was about 17% with the ISO intense smoking regime, similar to the transfer of nicotine. The menthol content of the novel product THS 2.2 corresponds to the midpoint of the menthol content range of cigarettes, and the transfer of menthol to its aerosol is in the low range of cigarette menthol transfer.

Comprehensive comparative compositional study of the vapour phase of cigarette mainstream tobacco smoke and tobacco heating product aerosol

A simple direct sample collection/dilution and introduction method was developed using quartz wool and Tenax/sulficarb sorbents for thermal desorption and comprehensive two-dimensional gas chromatography (TD-GC × GC) analyses of volatile organic compounds from vapour phase (VP) fractions of aerosol produced by tobacco heating products (THP1.0) and 3R4F mainstream tobacco smoke (MTS). Analyses were carried out using flame ionisation detection (FID) for semi-quantification and both low and high resolution time-of-flight mass spectrometry (LR/HR-TOFMS) for qualitative comparison and peak assignment. Qualitative analysis was carried out by combining identification data based on linear retention indices (LRIs) with a match window of ±10 index units, mass spectral forward and reverse library searches (from LR and HRTOFMS spectra) with a match factor threshold of >700 (both forward and reverse), and accurate mass values of ± 3 ppm for increased confidence in peak identification. Using this comprehensive approach of data mining, a total of 79 out of 85 compounds and a total of 198 out of 202 compounds were identified in THP1.0 aerosol and in 3R4F MTS, respectively. Among the identified analytes, a set of 35 compounds was found in both VP sample types. Semi-quantitative analyses were carried out using a chemical class-based external calibration method. Acyclic, alicyclic, aromatic hydrocarbons and ketones appeared to be prominent in 3R4F MTS VP, whereas larger amounts of aldehydes, ketones, heterocyclic hydrocarbons and esters were present in THP1.0 aerosol VP. The results demontsrate the capability and versatility of the method for the characterization and comparison of complex aerosol samples and highlighted the relative chemical simplicity of THP1.0 aerosol in comparison to MTS.

Evaluation of flavourings potentially used in a heated tobacco product: Chemical analysis, in vitro mutagenicity, genotoxicity, cytotoxicity and in vitro tumour promoting activity

We designed a novel tobacco-heating product (THP) that heats tobacco to release nicotine and aerosolised components, such as glycerol and tobacco volatiles from a tobacco rod (Neostik). Heating tobacco significantly reduces levels of combustion-derived toxicants in the aerosol compared to cigarette smoke. This study was conducted to determine whether the inclusion of potential flavourings in the THP would add to the levels of toxicants in the emissions or alter in vitro responses. Levels of measured toxicants were similar in the flavoured and unflavoured Neostik emissions and significantly less than emissions from the reference cigarette, 3R4F. No mutagenicity was observed with the Neostiks in the Ames test or in the mouse lymphoma assay. There was evidence of a weak genotoxic response in the in vitro micronucleus test using V79 cells from both Neostiks and these responses were less than 3R4F. They did not show tumour-promoting potential in the Bhas 42 cell transformation assay and were not cytotoxic in the Neutral Red uptake assay. 3R4F elicited toxic responses in all assays at significantly lower concentrations. The addition of flavourings to the Neostik tested did not alter the chemical profile of THP emissions or change in vitro responses relative to the unflavoured Neostik.

Investigation and comparison of the transfer of TSNA from tobacco to cigarette mainstream smoke and to the aerosol of a heated tobacco product, THS2.2

Tobacco-specific nitrosamines (TSNA) levels in tobacco cut filler and cigarette smoke were measured in more than 1000 commercially available cigarettes sampled between 2008 and 2014. Relative contributions to their transfer from tobacco to the mainstream smoke in terms of direct transfer by distillation, pyrorelease, and pyrosynthesis were evaluated on the basis of the comparison with the transfer of nicotine from tobacco to smoke. N'-nitrosonornicotine (NNN) was transferred essentially by distillation, while N'-nitrosoanatabine (NAT), 4-(methylnitrosamino)-1-(3-bipyridyl)-1-butanone (NNK) and N'-nitrosoanabasine (NAB) were transferred by pyrorelease or pyrosynthesis as well. In the case of the Tobacco Heating System 2.2, the transfer of nicotine from tobacco to the aerosol was similar to that observed for cigarettes, while the % transfer of TSNAs from tobacco to THS 2.2 aerosol was 2-3 times lower than in cigarettes. This difference is due to the fact that the tobacco is heated instead of burnt resulting in a lower direct transfer by distillation and a lower if any contribution of pyrosynthesis or pyrorelease.