an evaluation of electronic cigarette formulations and aerosols for harmful and potentially harmful constituents (hPhCs) typically derived from combustion

Introduction:
This article reports a study that aimed to determine the presence of harmful and potentially harmful constituents (hPhCs) in electronic cigarette (e-cigarette) formulations and aerosols, specifically focusing on combustion-related hPhCs. The study also assessed the transfer efficiency of these hPhCs from e-liquids to aerosols. The findings of this study can inform regulatory agencies and e-liquid manufacturers about the most meaningful analytes to include in regulatory guidance and quality control.

Key Points:

* The study used highly sensitive, selective, and validated analytical methods to analyze commercial rechargeable e-cigarettes with disposable cartridges and refill e-liquids.
* The combustion-related hPhCs, such as volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (Pahs), were not detected at measurable levels in the commercial and reference e-liquids or e-cigarette aerosols tested.
* When combustion-related hPhCs were added to the e-liquids, they transferred to the aerosol with transfer efficiencies ranging from 49% to 99%.
* The transfer efficiency of hPhCs was proportional to the amount of aerosol generated and was not affected by the coil heating time.
* The stability of VOCs and Pahs in the e-liquids was found to be low, with more than 95% of VOCs lost within 90 hours and B[a]P falling out of solution or being retained by the cartridge.
* Considerable measures were taken throughout the study to avoid contamination from conventional cigarette smoke.
* The study recommends that manufacturers of e-cigarettes monitor the e-cigarette e-liquid and aerosol chemistry through comprehensive stability studies to determine the product's shelf-life and factors that affect its stability.

Main Message:
The study found that combustion-related hPhCs are not present at measurable levels in commercial and reference e-liquids or e-cigarette aerosols tested. however, when combustion-related hPhCs were added to the e-liquids, they transferred to the aerosol with transfer efficiencies ranging from 49% to 99%. The study recommends that manufacturers of e-cigarettes should conduct comprehensive stability studies to determine the product's shelf-life and factors that affect its stability, while taking into account the low stability of VOCs and Pahs in the e-liquids. These findings can inform regulatory agencies and e-liquid manufacturers about the most meaningful analytes to include in regulatory guidance and quality control.

Wagner, Karl a., Jason W. Flora, Matt S. Melvin, Karen C. avery, Regina M. Ballentine, anthony P. Brown, and Willie J. McKinney. “an Evaluation of Electronic Cigarette Formulations and aerosols for harmful and Potentially harmful Constituents (hPhCs) Typically Derived from Combustion.” Regulatory Toxicology and Pharmacology 95 (June 2018): 153–60. https://doi.org/10.1016/j.yrtph.2018.03.012.