Comparison of design characteristics and toxicant emissions from Vuse Solo and Alto electronic nicotine delivery systems

Composition of e-cigarette aerosols: A review and risk assessment of selected compounds

The potential harms and benefits of e-cigarettes, or electronic nicotine delivery systems (ENDS), have received significant attention from public health and regulatory communities. Such products may provide a reduced risk means of nicotine delivery for combustible cigarette smokers while being inappropriately appealing to nicotine naive youth. Numerous authors have examined the chemical complexity of aerosols from various open- and closed-system ENDS. This body of literature is reviewed here, with the risks of ENDS aerosol exposure among users evaluated with a margin of exposure (MoE) approach for two non-carcinogens (methylglyoxal, butyraldehyde) and a cancer risk analysis for the carcinogen N-nitrosonornicotine (NNN). We identified 96 relevant papers, including 17, 13, and 5 reporting data for methylglyoxal, butyraldehyde, and NNN, respectively. Using low-end (minimum aerosol concentration, low ENDS use) and high-end (maximum aerosol concentration, high ENDS use) assumptions, estimated doses for methylglyoxal (1.78 × 10-3-135 μg/kg-bw/day) and butyraldehyde (1.9 × 10-4-66.54 μg/kg-bw/day) corresponded to MoEs of 227-17,200,000 and 271-280,000,000, respectively, using identified points of departure (PoDs). Doses of 9.90 × 10-6-1.99 × 10-4 μg/kg-bw/day NNN corresponded to 1.4-28 surplus cancers per 100,000 ENDS users, relative to a NNN-attributable surplus of 7440 per 100,000 cigarette smokers. It was concluded that methylglyoxal and butyraldehyde in ENDS aerosols, while not innocuous, did not present a significant risk of irritant effects among ENDS users. The carcinogenic risks of NNN in ENDS aerosols were reduced, but not eliminated, relative to concentrations reported in combustible cigarette smoke.

Benchmarking a universal smoking machine adaptor for tobacco product testing

SIGNIFICANCE

Characterisation of tobacco product emissions is an important step in assessing their impact on public health. Accurate and repeatable emissions data require that a leak-tight seal be made between the smoking or vaping machine and the mouth-end of the tobacco product being tested. This requirement is challenging because of the variety of tobacco product mouth-end geometries being puffed on by consumers today. We developed and tested a prototype universal smoking machine adaptor (USMA) that interfaces with existing machines and reliably seals with a variety of tobacco product masses and geometries.

METHODS

Emissions were machine-generated using the USMA and other available adaptors for a variety of electronic cigarettes (n=7 brands), cigars (n=4), cigarillos (n=2), a heated tobacco product, and a reference cigarette (1R6F), and mainstream total particulate matter (TPM) and nicotine were quantified. Data variability (precision, n≥10 replicates/brand) for all products and error (accuracy) from certified values (1R6F) were compared across adaptors.

RESULTS

TPM and nicotine emissions generated using the USMA were accurate, precise and agreed with certified values for the 1R6F reference cigarette. Replicate data indicate that USMA repeatability across all tobacco products tested generally meets or exceeds that from the comparison adaptors and extant data.

CONCLUSION

The USMA seals well with a variety of combustible tobacco products, e-cigarettes with differing geometries and plastic-tipped cigarillos. Variability for all measures was similar or smaller for the USMA compared with other adaptors.

Understanding the nicotine dose delivered by electronic nicotine delivery systems in a single puff: the importance of nicotine flux and puff duration

Electronic nicotine delivery systems (ENDS) may lead to public health benefit if they help people who smoke quit smoking, and may lead to public health harm if they recruit a new generation of nicotine-dependent people. Regulators intent on maximising ENDS' public health benefit and minimising harm may be interested in regulating the nicotine dose delivered by ENDS in a single puff. The per-puff nicotine dose is the product of ENDS nicotine emission rate (or 'nicotine flux') and the duration of the puff taken by the person using the ENDS (or 'puff duration'). Nicotine flux can be measured or predicted mathematically for any ENDS device/liquid combination. Puff duration can be controlled electronically, as demonstrated by several ENDS marketed today. Combining nicotine flux and puff duration regulation is feasible today and provides authorities the means to limit nicotine dose per puff to a level that may help people who smoke quit smoking while reducing the possibility that nicotine-naive individuals will engage in repeated ENDS use. Tobacco regulatory science and product regulation will both be improved by a rigorous approach to understanding, characterising, and reporting the nicotine dose emitted by ENDS.

Evaluation of Cytotoxicity and Oxidative Stress of Whole Aerosol from Vuse Alto ENDS Products

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.

Effect of third-party components on emissions from a pod style electronic cigarette

Electronic nicotine delivery systems (ENDS) have been associated with a dramatic increase in youth becoming addicted to nicotine following decades-long decline in cigarette smoking uptake. The United States Food and Drug Administration, Center for Tobacco Products (FDA/CTP) is responsible for regulating devices and consumable materials associated with ENDS. State and federal regulations regarding flavoring compounds in ENDS liquids (e-liquids) may be circumvented when vendors market refillable reservoirs side-by-side with noncompliant e-liquids. This study investigated the effect of third-party refillable versus manufacturer-supplied single-use reservoirs on total particulate matter (TPM) and nicotine emissions. The maximum TPM yield per puff was 5.6 times higher for the third-party (Blankz) reservoir (12.4 mg/puff) in comparison with the manufacturer's (JUUL) reservoir (2.2 mg/puff), whereas the maximum TPM concentration was over 7 times higher for third party (0.200 mg/ml) versus manufacturer (0.028 mg/ml) pod. The third-party pod was tested with nicotine concentrations ranging from 0% to 4%. The mass ratio of nicotine present in the aerosol (mg Nic/mg TPM) was found to be approximately the same as the mass ratio of the e-liquid (mg Nic/mg e-liquid) for both pods and all 3 nicotine laden e-liquids tested. Toxicant exposure may increase when consumers use third-party pods with ENDS devices. Refillable reservoirs are a significant barrier to regulatory restrictions on potentially toxic additives to e-liquids. It is recommended FDA/CTP require emissions characterization of third-party reservoirs used with each ENDS they are compatible with and should be required to demonstrate no increased potential toxicant exposure in comparison with manufacturer-provided reservoirs.