Cytotoxicity and acute toxicity assessment of several typical nicotine salts
As a new form of nicotine intake, nicotine salts are increasingly used in new tobacco products such as electronic cigarette. Whether the matrix components of electronic liquids will affect its toxicity, relative to pure nicotine, how to set the concentration limits of nicotine salts in electronic liquids to avoid the risk of misuse, and their inhalation toxicity on lung cell are all important issues deserving attention. Therefore, in this study, the matrix effect of electronic liquid was investigated first; and then 7 representative nicotine salts were selected to test their acute oral toxicity based on rats, and finally their pulmonary cytotoxicity was test based on BEAS-2B cells. The results showed that: (1) The LD50 values of pure nicotine and simulated electronic liquid with the same nicotine equivalent were very close to each other; (2) The LD50 values of acute oral toxicity of 7 nicotine salts were higher than that of nicotine; (3) The IC50 values of the cytotoxicity of 7 nicotine salts were significantly different, partly higher than nicotine and partly lower than nicotine. In conclusion, it can be inferred that the matrix components of electronic liquids have little effect on nicotine toxicity; the general toxicity of these nicotine salts is lower than that of nicotine, which can provide a reference for setting maximum limits of these nicotine salts in electronic liquids; the pulmonary cytotoxicity of different nicotine salts was significantly different, and the pulmonary cytotoxicity of several nicotine salts was much higher than that of nicotine. Further studies on inhalation toxicity of nicotine salts are needed in the future to guide the application of nicotine salts in electronic liquids.