Comprehensive Chemical Characterization of the Aerosol Generated by Heated Tobacco Product

      Bentley, Mark

      Conference date
      Feb 24, 2021
      Conference name
      SRNT 2021

      Below is the transcript of the video:

      Hello, I'm Mark Bentley and I work for Philip Morris International at their R&D facility based in Neuchâtel, Switzerland. First of all, I'd like to thank the organizers for giving me the opportunity to present this research, where I will share with you the results from the Chemical Characterization of the Aerosol Generated by a Heated Tobacco Product. This is represented by our Tobacco Heating System, THS. 

      When tobacco is heated instead of being burned, the aerosol that is generated contains fewer and lower levels of chemical constituents than cigarette smoke, which is widely understood to contain more than 6000 chemical constituents with around 100 of these known to be linked to smoking-related disease. Targeted analysis, which focuses on the quantification of known chemicals to the exclusion of all others, has demonstrated that the average levels of known harmful and potentially harmful constituents (HPHCs) are reduced in THS aerosol in the range of 90 to 95% relative to cigarette smoke, depending upon the list of targeted HPHCs. However, because there is a possibility that additional unknown harmful constituents could be present, untargeted analysis of the aerosol was also performed. Untargeted analysis aims to identify and semi-quantify all chemical constituents within a matrix. And in order to achieve this, a suite of complementary methods was used, which was developed to cover the large chemical space associated with cigarette smoke and heated tobacco aerosols. 

      For untargeted screening, a threshold of 100 nanograms per stick was used for the reporting of chemical constituents in smoke or aerosol. The term “stick” here refers to the heat stick used with THS or a cigarette. Applying this threshold, we estimate there are tenfold fewer compounds present in THS aerosol compared with 3R4F smoke. In addition, all 532 compounds present in the aerosol of THS above this threshold were also present in the smoke of the 3R4F reference cigarette.

      Overall, more than 96% of the total mass characterized by untargeted screening, representing over 80% of the total number of compounds identified, was confirmed with reference standards. The untargeted differential screening approach does not apply a reporting threshold, and focuses on identifying all compounds that are higher in abundance in the aerosol of THS compared with 3R4F smoke.

      Using this approach, we reported a combined number of 85 compounds as being more abundant in THS aerosol across the three heat stick product variants authorized for marketing in the United States, two mentholated and one regular non-mentholated variant. Nine of these 85 compounds were unique to THS aerosol. Information regarding these 85 compounds, including an in-house toxicological evaluation, was provided to the FDA, who concluded their presence was not of toxicological concern relative to cigarette smoke. The compounds uniquely present in THS aerosol are primarily attributable to tobacco blend differences and presence of flavor compounds, as 3R4F is an unflavored product. If we focus on the results for the U.S. authorized regular heat stick variant, which is non-mentholated, 54 compounds were identified as being more abundant in THS aerosol compared with 3R4F smoke, three of which were unique in THS aerosol.

      Based on their review of our premarket tobacco product application for THS, their own testing, and a review of published literature, the FDA concluded that: “Although some of the chemicals are genotoxic or cytotoxic, these chemicals are present in very low levels, and potential effects are outweighed by the substantial decrease in the number and levels of HPHCs found in combusted cigarettes.”

      So, to conclude, using untargeted screening, we have confirmed that the aerosol generated by THS is significantly less complex than cigarette smoke, with 532 chemical constituents above 100 nanograms per stick, identified as being present in the aerosol of non-mentholated or regular product variant, which is approximately tenfold fewer than in the smoke of the 3R4F reference cigarette, applying the same reporting threshold with confirmed identity for over 96% of the total THS aerosol mass being determined.

      Using untargeted differential screening, we have highlighted the presence of any compounds with increased abundance in THS aerosol relative to 3R4F cigarette smoke. A total of 85 compounds were found to be in higher abundance in THS aerosol for the three U.S. authorized product variants, nine of which being unique. These more abundant constituents were not considered to be of toxicological concern, and were attributable to differences in tobacco blend and the presence of flavors, since 3R4F is an unflavored cigarette. Overall, based on the outcome of our research, we can conclude that the aerosol generated by

      THS has been characterized to the fullest practicable extent. With that, I'd like to thank you for your attention.

      Important: This presentation is for the purpose of publishing and disseminating scientific information about Philip Morris International’s efforts to develop and assess products that have the potential to reduce individual risk and population harm associated with tobacco use. This presentation is for audiences of scientists, public health and regulatory communities, and other stakeholders with an interest in tobacco policy. The purpose is not advertising or marketing. It is not intended for use by consumers.

      Nothing in this presentation should be construed as making any representation, express or implied, that the FDA has approved or has otherwise endorsed IQOS.