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Alicia Paini 
esqLABS GmbH

Dr. Paini studied Food Science and Technology at the University of Parma (2005) she received an  MSc in Food Safety (2007) and a doctorate in Toxicology from Wageningen University (2012). The  Ph.D. was performed at the Nestlé Research Center near Lausanne (Switzerland), she also is a  European Registered Toxicologist (ERT) since 2013. Alicia was a postdoctoral scholar at the  European Commission Joint Research Center (EC-JRC) from 2012 to 2015. In 2015, she continued  working as a scientific project officer at the EC JRC, promoting computational modelling in risk  assessment and policy making. Alicia was part of (and leading) the international group that drafted  the OECD GD on PBK models published in 2021 (OECD 331). She joined esqLABS GmbH in  October 2021, where she led research programs on developing and applying physiologically based  kinetic (PBK) models and developing strategies for next-generation risk assessment.

OpenTox Virtual Conference 2023

Title session: In vivo and in vitro distribution models for chemical risk assessment, November 10th, 13 – 15 CET 

Chair session description 

To assess chemical toxicity, there is a need to capture the chemical´s mode of action, including  both biokinetic and dynamic-effect processes. Information on the human biokinetics, or  biological fate of a substance, plays an essential role in safety assessment. This session will  present and describe chemical distribution and biokinetic processes using mathematical models. These models can be classified into two sets: (i) In vitro distribution models  representing, by means of mathematical equations, the chemical distribution in an in vitro well that takes into consideration experimental conditions. (ii) In vivo distribution models,  represented by Physiologically Based Kinetic (PBK) models, that describe mathematically the  chemical distribution in vivo. Both types of models alone and in synergism will help in the  refinement of testing strategies and risk assessment. The following talks will present in detail these models and their applications in different areas: 

1. S. Proenca: In vitro kinetics as a cornerstone for QIVIVE and IVIVE. 

2. A. Paini: In vivo distribution using OSPS - PKSim for chemical risk assessment  3. M. Iulini: In silico method to study immunotoxicity: PFAS case study 

4. L. Lautz: TKPlate: Examples of an open access tool for kinetic modelling in farm animal  species 

At the end of the lineup, there will be time for a short round table on challenges and obstacles in  applying these tools in risk assessment.

In vivo distribution using OSPS - PKSim for chemical risk assessment 

Open-source tools have recently gained popularity, offering a cost-effective and collaborative approach. The PK-Sim, is one of these tools, designed as an open-source physiologically-based  kinetics (PBK) modelling and simulation tool for drug development and chemical risk assessment (, available on GitHub). PBK modelling is  used to simulate the in vivo distribution of chemicals in the body (blood and organs) by means  of absorption, distribution, metabolism, and excretion (ADME) processes. These models enable a quantitative link between external exposure dose and internal concentration with toxicological data to derive safe levels of chemicals. PBK modelling is traditionally performed for individual compounds, iteratively integrating data from animal or human studies. There is a current shift in  the development and application of generic high-throughput models to help classify and prioritise large amounts of chemicals (e.g. contaminants). This talk will introduce the PKSim tool and its application to assess chemicals in different sectors.