Aerosol Physics

      Product Stability and Robustness

      Our smoke-free products are designed to reduce exposure to a range of harmful and potentially harmful constituents (HPHCs) and before biological testing we verify the performance of the products by measuring the aerosol chemistry under standardized machine-smoking conditions. We are, however, also verifying that the product performance is maintained with time or usage under a range of real-life situations (such as climatic conditions and puffing patterns).

      Product stability

      To verify the product stability and establish a product shelf life, we follow international standards, in particular the guidance from the International Conference of Harmonization (ICH) and the U.S. Food and Drug Administration (FDA). Samples from multiple batches of finished products are stored under predefined conditions, including the World Health Organization (WHO) climatic zones defined in the ICH guidelines (Q1).

      Learn more about the ICH and U.S. FDA guidelines we follow:

      Different time points are defined, where selected batches are tested for a range of HPHCs in the aerosol, physical and chemical characteristics, sensory property of the product, and visual inspection.

      For quantitative data, all values measured are then aggregated together to build a regression model for the time evolution and the confidence limit for every parameter followed in the course of the aging study. The confidence level is then compared to a pre-established specification to define the shelf life of the product.


      Product robustness under various climatic conditions

      Our smoke-free products will be used in different regions; therefore, we need data to demonstrate that the products performance will be maintained in various climatic conditions.

      To do that, we have a climatic smoking machine, enabling testing the products under defined humidity and temperatures. We use the temperature and humidity ranges covering the WHO climatic zones defined in ICH guidelines (Q1), also used for aging studies.

      The results published by Poget et al. (2021) indicate that, regardless of the considered climatic conditions, the HPHC levels investigated in our Tobacco Heating System (THS) 2.2 aerosol were reduced by at least 90%, on average, when compared with the levels measured in 3R4F cigarette mainstream smoke. This confirmed the robustness in performance for THS 2.2 to deliver reduced levels of HPHCs under extreme climatic conditions.

      Product robustness under different puffing regimes

      How a person puffs a cigarette or a smoke-free product varies, and therefore we need to evaluate product performance under different puffing regimes that we have developed, for example as described by Goujon et al. (2020).

      Using this range of puffing regimes, HPHCs are measured and then plotted versus nicotine deliveries, to verify that their levels are kept in proportion to nicotine, with the ratio of HPHCs to nicotine either constant or decreasing.

      Independently to nicotine levels, comparable robustness of reduction was observed in the study published by Poget et al. (2017) showing that, under various regimes, the reduction of the concentration of investigated HPHCs in THS 2.2 is more than 90% by comparison with reference cigarette mainstream emissions (3R4F). This product behavior ensures that the reduced exposure compared to cigarette use is maintained, regardless of the puffing patterns.