Characterization of electronic cigarette formulations and aerosol
E-cigarettes, also known as E-vapor products and electronic nicotine delivery systems, are gaining popularity in the U.S. and global markets. Currently, limited published data exists on the formulations and chemicals that may be formed during aerosol generation. A harmful and potentially harmful constituent (HPHC) list developed for currently regulated tobacco products includes several chemical classes such as carbonyls, aromatic amines, volatile organic compounds, polyaromatic hydrocarbons and tobacco specific nitrosamines (TSNAs). The E-vapor product category, however, is currently not regulated and no specific list of HPHCs exists. Most e-cigarette formulations contain propylene glycol (PG) and glycerin, which are known to produce aldehydes when heated. In addition, ethylene glycol, diethylene glycol and nicotine related chemicals have been previously reported as potential e-cigarette formulation impurities. Our objective was to evaluate NuMark’s commercial e-cigarette formulations and aerosols for the chemicals listed above, determine toxicological significance and share results with the scientific community. Aerosols were collected using 4 second puffs, 55 cc puff volumes, and 30 second puff intervals. E-cigarettes were puffed to battery exhaustion to maximize aerosol collection. For carbonyls analysis, aerosols were collected in 20 puff increments to account for analyte instability. TSNAs were measured at levels acceptable in US pharmacopeia grade nicotine. Nicotine related impurities in NuMark’s e-cigarette formulations were below levels suggested by ICH guidelines Q3B(R2) (<0.5% of the total nicotine concentration). The levels of thermal degradation products from PG and glycerin detected in the aerosol were determined to be toxicologically insignificant.