Analytical method to model human mouth-level transfer of ingredients from Swedish pouched snus
In parallel with the human study a laboratory in vitro assay was conducted with three media: artificial saliva, water and 1% ß-cyclodextrin in water, using two snus products that were indistinguishable apart from the flavour application rate. To determine an analytical method to model human mouth-level transfer, the transfer rates for each ingredient (menthol, 1,8-cineole and nicotine) were compared using extraction times of 5, 10 or 30 minutes with 30 mL of each of the preheated (370 °C) extraction solvents.
For measuring residual flavours on exposed snus pouches, preliminary extraction tests highlighted quantitative salivary effects with some users. Dichloromethane/Methanol (1:1 v/v) was found to lead to an efficient extraction >95% for all three targeted compounds.
With an extraction time of 30 minutes no artificial media provided a good correlation with the human data. The transfer rates of all media vs. human data set was highest for nicotine (78% to 89%) than 1,8-cineole (ranging from 44% to 69%) and menthol (25% to 60%); for both application rates.
At shorter contact times (10 and 5 minutes) flavour transfer rates for water and artificial saliva were similar but significantly higher for ß-cyclodextrin. Nicotine transfer rates remained highest and overestimated transfer. The 1% ß-cyclodextrin in water enhanced organic solvent extraction (both dichloromethane and dichloromethane/methanol). This media also exhibited higher transfer rates for all contact times (30, 10 and 5 minutes) for the three compounds studied.
An extraction time of 5 minutes into artificial saliva or water gave the best fit to the human data set for all three compounds. The relative extraction of the three constituents reflected the water solubility. In the human data, saliva access may limit upper transfer rates. As was seen in the human study, application rates did not appear to affect transfer rates in any media.
 Human mouth-level transfer rate of menthol, 1,8 cineol and nicotine from Swedish pouched snus. Oral session - CORESTA 2013.