Embedded PBK models

The following generic PBK models are currently implemented in MCRA:

• EuroMix generic PBK model of Tebby et al. (2020).

• Bisphenol PBK model ETHZ of Karrer et al. (2019).

The MCRA interface allows to run PBK models for any number of days and supplies an option to skip an initial number of days (build-up phase PBK model) in the calculation of the internal exposure.

In the original bisphenol PBK model of Karrer et al. (2019), doses were applied on fixed time points and only for the first four days. For oral exposure, three dosings per day with t = 0, 6 and 12 h, for dermal exposure to PCPs and TP, two dosings per day with t = 0 and 12 h. The steady state was reached after dosing on four consecutive days. Therefore, the bisphenol PBK model described in Karrer et al. should be run for four days to reached steady state and the number of initial days to be skipped should be set to 0. Note, no dosing is applied from day 5th onwards.

These restrictions were relaxed in a new implementation of the bisphenol PBK model (General Model BPA Re-implementation). In this new version the number of days is unlimited. Dosings are specified through the user interface including the definition on the non-stationary period, see settings PBK models.