Master intership - iSafeRat® SAb: a prediction model for skin absorption
Type de contrat: Internship
Location: KREATiS office (L'Isle d'Abeau)
Date of beginning: ~02/02/2026
Internship : PBK model
Start date : February
2026
Length : 6 months
Locality : KREATiS office (L'Isle d'Abeau)
Level of
diploma : Master 2 / Bac+5
Context
Under European regulations of chemicals (REACH, pesticides, cosmetics, medicines) substances are generally evaluated using in vivo or in vitro experimental methods following OECD guidelines. These tests can be long and expensive to perform and they are not acceptable anymore on an ethical point. To help the chemical industry to limit experimentation, KREATiS offers in silico alternatives to experimentation according to the 3Rs principles (Replace – Reduce – Refine). The aim of KREATiS is to provide in silico models which are as accurate and reliable as good laboratory studies.
Website : KREATiS : https://www.kreatis.eu/
Purpose
The skin is one of the main route of exposure for many chemicals, especially for cosmetics and topically applied medication. Thus, testing methods are needed in order to estimate the skin penetration or absorption of substances. Many experimental protocols can be designed, but they need to be thorough enough to satisfy the regulatory requirements. To ensure the quality of an laboratory experiment, the OECD (Organisation for Economic Co-operation and Development) produces guidelines to act as standards in safety testing. In silico test methods based on computer models can predict skin penetration or absorption parameters from various input variables. The models used are usually QSARs such as iSAFERAT® (1), or physiologically based pharmacokinetic modelling (PBPK), which is a kind of compartment model. These methods allows for a total replacement of animal testing once the model is fully validated, and can be tuned for human skin characteristics. Running simulations is also quicker and cheaper than experimental studies. Even if several in silico models for skin penetration (epidermal passage including stratum cornea) are still available, no existing model is available to estimate the skin absorption of substance , i.e. diffusion of the substance from the dermis into the blood.
It is proposed to participate in the Research & Development of skin absorption model from the current skin penetration model.
For the project needs, a training will be given to the intern in order for him/her to have a sufficiently high level of understanding of the subject and the test performed (OECD guidelines) to measure the in vitro skin penetration and the in vivo skin absorption of a substance (2).
An existing in vitro study is used to assess the skin penetration (OECD guideline 428). An in vivo study is used to assess the skin absorption (OECD guideline 428). KREATiS wants to build a reliable database based on both OECD TG 427 and OECD TG 428 validated data.
Thus, the intern will collect all available data from documented databases (ECHA website) validate it and assess the reliability of each studies. Experimental data will also be provided by a private company that already collaborates with KREATiS.
From the collected data, a dataset with only the best quality OECD 428 data will be used to validate the existing skin penetration model that has been improved including the penetration via follicular/sebum. Improvements of this model has to be made depending on the robustess of the model.
Then a worst-case first adaptation of the skin penetration model to the skin absorption using physiological and mathematical parameters, can be started within this training.
The work will be supervised by a multidisciplinary team and different consideration will be taken to develop the most reliable model of skin penetration and a first version of the skin absorption (worst-case absorption).
The meeting with the KREATiS partner team (located at Toulouse) and the visit to their laboratory conducting in vitro skin penetration studies, are scheduled at the beginning of the internship. Knowledge in mammal physiology, biochemistry and modelling using excel and python are required as well as good analytical skills and a B2 level of English.
At the end of the project the intern will have a good understanding of how to validate input data for in silico model development, will have learned how to set up a dataset to build a PBK of good quality and will have a general comprehension of alternative methods, such as in silico techniques.
(1) iSafeRat® – in Silico Algorithms For Environmental Risk And Toxicity (2014) https://isaferat.kreatis.eu/(2) OECD Guideline for testing of chemicals No. 428 for in vitro skin penetration and No. 427 for in vivo skin absorption
