Characterization of potential impurities and degradation products in electronic cigarette formulations and aerosols

• Published in: Regulatory toxicology and pharmacology 2016-02, Vol.74, p.1-11
• Main Authors: Flora, Jason W., Meruva, Naren, Huang, Chorng B., Wilkinson, Celeste T., Ballentine, Regina, Smith, Donna C., Werley, Michael S., McKinney, Willie J.
• Format: Article
• Language: English
• Subjects: Aerosol; Aerosols; Aldehydes - adverse effects; Aldehydes - analysis; Ammonia - analysis; Arsenic - analysis; Cadmium - analysis; Chemistry, Pharmaceutical; Drug Contamination; Drug Stability; E-cigarettes; E-vapor; Electronic Nicotine Delivery Systems - adverse effects; Formulation; Harmful and potentially harmful constituents (HPHC); Humans; Nicotine - adverse effects; Nicotine - analysis; Nicotinic Agonists - adverse effects; Nicotinic Agonists - analysis; Nitrosamines - adverse effects; Nitrosamines - analysis; Risk Assessment; Volatilization
• ISSN: 0273-2300; 1096-0295
• DOI: 10.1016/j.yrtph.2015.11.009

E-cigarettes are gaining popularity in the U.S. as well as in other global markets. Currently, limited published analytical data characterizing e-cigarette formulations (e-liquids) and aerosols exist. While FDA has not published a harmful and potentially harmful constituent (HPHC) list for e-cigarettes, the HPHC list for currently regulated tobacco products may be useful to analytically characterize e-cigarette aerosols. For example, most e-cigarette formulations contain propylene glycol and glycerin, which may produce aldehydes when heated. In addition, nicotine-related chemicals have been previously reported as potential e-cigarette formulation impurities. This study determined e-liquid formulation impurities and potentially harmful chemicals in aerosols of select commercial MarkTen® e-cigarettes manufactured by NuMark LLC. The potential hazard of the identified formulation impurities and aerosol chemicals was also estimated. E-cigarettes were machine puffed (4-s duration, 55-mL volume, 30-s intervals) to battery exhaustion to maximize aerosol collection. Aerosols analyzed for carbonyls were collected in 20-puff increments to account for analyte instability. Tobacco specific nitrosamines were measured at levels observed in pharmaceutical grade nicotine. Nicotine-related impurities in the e-cigarette formulations were below the identification and qualification thresholds proposed in ICH Guideline Q3B(R2). Levels of potentially harmful chemicals detected in the aerosols were determined to be below published occupational exposure limits. •Most potential impurities or degradation products were not detectable.•Impurities or degradation products found were below occupational exposure limits.•Study provides insights regarding constituents that can be present in e-cigarettes.•Standardized puffing regimes and testing methodologies for e-cigarettes is needed.