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IntroductionModern oral nicotine pouch products (ONPs) are a category of oral nicotine products which contain pharmaceutical-grade nicotine, flavors, and other food-grade ingredients but no tobacco leaf. Recent reports indicate that ONPs in general do not contain (or only at minimal levels) the harmful and potentially harmful constituents (HPHCs) identified in cigarette smoke, suggesting their potential as alternative products for reducing harm from cigarette smoking.MethodsWe assessed in vitro toxicological effects of eight ONPs, designated as modern oral (MO) 1 to 8 along with an ONP, an oral tobacco (snus), and a combustible cigarette market comparator using established regulatory toxicological assays including Ames, in vitro micronucleus (ivMN), and neutral red uptake (NRU) assays.ResultsThe MO test products 1-7 ZYN wintergreen, and General Snus white mint were negative for mutagenicity (Ames assay), genotoxicity (ivMN), and cytotoxicity (NRU). The combustible cigarette was positive in all three assays. The MO-8 test product was negative for mutagenicity; however, it was positive in the ivMN and NRU assays at concentrations either 42 to 135-fold based on the ivMN i to iv treatment schedule or 60-fold higher, respectively, when compared to combustible cigarettes.DiscussionThus, the MO test products are likely to be less harmful than combustible cigarettes and are alternatives to cigarettes. However, understanding of long-term effects of ONPs in general requires additional research.

Compared to cigarette smoke, heated tobacco product (HTP) aerosol contains significantly fewer and lower levels of harmful and potentially harmful constituents (HPHCs). However, the impact on environmental air is relatively unexplored. Therefore, this study compared levels of secondhand aerosol (SHA) constituents in air following glo HTP use with secondhand smoke (SHS) constituents following cigarette smoking in an environmental test chamber (ETC). Extracted ETC air samples following product use sessions were analyzed for 27 SHS/SHA constituents, including HPHCs. The use of glo HTPs resulted in significantly lower SHA HPHC levels in the ETC air relative to SHS HPHC levels from cigarette smoking. Some aerosol constituents (benzene, CO, formaldehyde, nicotine, respirable suspended particles, toluene, ethylbenzene, fine particulate matter, m- and p-cresol, o-cresol, pyridine, styrene, and ultraviolet particulate matter) were either below the limit of detection in ETC air or at significantly low levels following glo HTP use relative to cigarette smoking. Mean concentrations of the assessed constituents were at least 90 % lower following use of glo HTPs compared to smoking combustible cigarettes. These results suggest that glo HTP use would not contribute significantly to indoor air contamination and would reduce non-user exposure to HPHCs and other harmful constituents relative to combustible cigarettes. Such reductions in non-user exposure should be considered when assessing the tobacco harm reduction potential of glo HTPs.

Abstract We report the findings from a randomized, parallel study designed to evaluate nicotine pharmacokinetics (PK) following 10 min of ad libitum use of electronic nicotine delivery system (ENDS) in four flavor variants. Subjects were randomized an investigational product (IP) and blood samples were collected for PK assessments during a test session. Primary endpoints were baseline-adjusted values of maximum plasma nicotine concentration (Cmax) and area under the nicotine concentration-vs-time curve up to 60 min (AUCnic0–60). Baseline-adjusted mean Cmax ranged from 6.53 to 8.21 ng/mL, and mean AUCnic0–60 ranged from 206.87 to 263.52 ng min/mL for all ENDS IPs. Results of geometric mean Cmax and AUCnic0–60 values were within 95% confidence intervals (CI) among the ENDS IP flavor variants tested.

Assessment of in vitro cytotoxicity is an important component of tobacco product toxicological evaluations. However, current methods of regulatory testing involve exposing monolayer cell cultures to various preparations of aerosols from cigarettes or other emerging products such as electronic nicotine delivery systems (ENDS), which are not representative of human exposure. In the present study, a whole aerosol (WA) system was used to expose lung epithelial cultures (2D and 3D) to determine the potential of six Vuse Alto ENDS products that varied in nicotine content (1.8%, 2.4%, and 5%) and flavors (Golden Tobacco, Rich Tobacco, Menthol, and Mixed Berry), along with a marketed ENDS and a marked cigarette comparator to induce cytotoxicity and oxidative stress. The WA from the Vuse Alto ENDS products was not cytotoxic in the NRU and MTT assays, nor did it activate the Nrf2 reporter gene, a marker of oxidative stress. In summary, Vuse Alto ENDS products did not induce cytotoxic or oxidative stress responses in the in vitro models. The WA exposures used in the 3D in vitro models described herein may be better suited than 2D models for the determination of cytotoxicity and other in vitro functional endpoints and represent alternative models for regulatory evaluation of tobacco products.

The rapid development associated with Next Generation Tobacco Products (NGTP) has necessitated the development of high throughput methodologies to test their genotoxic potential in vitro when compared to conventional cigarette smoke (CS). An assessment of two Vitrocell® Mammalian 6/48 exposure modules in three independent experiments was made by comparing results from multiple dosimetric techniques applied to aerosol generated from 3R4F Kentucky Reference cigarettes, commercially available electronically heated tobacco product (eHTP) and Electronic Nicotine Delivery System (ENDS) using the Vitrocell® VC10®. Real-time aerosol particle concentration was assessed by means of light scattering photometers and expressed as area under the curve (∑AUC). Nicotine concentrations were determined analytically by LC/MS. Humectant amount and distribution was assessed for eHTP and ENDS by the quantification of free glycerol in a phosphate buffered saline (PBS) trap, whereas total particulate matter (TPM) was assessed in the 3R4F cigarettes by the fluorescence of the particulate at 485 nm in anhydrous dimethyl sulfoxide (DMSO) trap within the exposure. Dose was adjusted by means of the addition of ambient air to dilute the whole smoke/aerosol in L/min and sampled into the system at a rate of 5 mL/min. Dilution of CS ranged from 8.0 to 0.5 L/min and for the eHTP and ENDS ranged from 4 to 0 L/min (undiluted). Dosimetric analysis of the system showed good concordance within replicates (p-values ranged from p = 0.3762 to p = 0.8926) and showed that the Vitrocell® Mammalian 6/48 is a viable means for genotoxic assessment of aerosol generated from both conventional cigarettes and NGTP. Results demonstrate the need to tailor dosimetry approaches to different aerosols due to variations in the physio-chemical composition, with a multi-dosimetry approach recommended.

The Vitrocell® VC10® smoke exposure system offers multiple platforms for air liquid interface (ALI) and air agar interface (AAI) exposure that mimic in vivo conditions for assessing toxicological impact of whole smoke using in vitro assays. The aim of this study was to investigate and compare multiple dosimetry techniques that may be employed during combustible cigarette whole smoke exposure using the Vitrocell® VC10® smoking robot. The following techniques were assessed: (1) quartz crystal microbalances (QCMs), (2) aerosol photometers (using area under curve, AUC), and (3) fluorescence of anhydrous dimethyl sulfoxide (DMSO)-captured smoke constituents.Results showed that each of the dosimetry techniques was able to distinguish different levels of whole smoke airflow in a concentration-related manner. When compared to each other, the three techniques showed a high level of consistency and all were considered efficient tools in quantifying dose during an exposure, although higher variation was observed at the higher airflows tested. Overall, the dosimetry tools investigated here provide effective measures of the whole smoke concentrations tested during the exposure. Keywords: Whole smoke, Smoke exposure system, Dosimetry, Aerosol, Photometers