The project aims to address minimum requirements of the toxicokinetic study design to accommodate testing of (nano)particles. The requirements will be based on the anticipated presence of (nano)particles in the different target tissues and the ability to detect the (nano)particles or determinants thereof (e.g., the radiolabel, fluorescent functional group or chemical components of the (nano)particles) in tissues.
Second commenting round on the draft guidance document on toxicokinetics to accommodate testing of (nano)particles
- Submission period
- 22 Dec 2025 - 10 Feb 2026
Background public consultation
Project description
The new Guidance Document proposes minimum requirements of the toxicokinetic study design for (nano)particles based on (i) the dosing regimen (administration mode, level and/or range, frequency and duration), (ii) the duration of the post exposure period, (iii) the time points for determining organ or tissue burdens (during and post exposure), and (vi) the key organs, tissues and/or excreta to be analysed. The Guidance Document also addresses issues such as choice of test species and sex and route of exposure, with a focus on inhalation and oral administration. Discussion on the need for adequate preparation and physico-chemical characterisation of the (nano)particles in the administration vehicle/matrix is also within the scope of the new Guidance Document.
How to contribute
The draft Guidance Document on toxicokinetic to accommodate testing of (nano)particles is currently under a commenting round by the Working Party of the National Coordinators of the Test Guidelines Programmes and open for comments from the public at the same time. Interested parties are invited to contact their National Coordinators at least a week before 10 February 2026.
