The Organisation for Economic Co-operation and Development has published a new guidance document addressing toxicokinetics testing specifically designed to accommodate the study of (nano)particles.
Posted on August 10, 2026, the document provides detailed guidance around in vivo testing for toxicokinetics of manufactured particles following oral and inhalation exposure routes.
The guidance focuses specifically on simple-structured, poorly soluble, and partially soluble spheroidal particles, reflecting a targeted approach to a technically complex area of chemical safety testing.
OECD has adopted the distinctive bracketed term “(nano)particles” throughout the document to signal that both nano-sized and larger particles fall within its scope.
This terminological choice reflects a deliberate effort by OECD to avoid limiting the guidance to nanoscale materials alone, broadening its practical applicability across particle sizes.
The primary focus of the document is on inorganic (nano)particles, though OECD acknowledges that some of the information included will also be relevant to organic materials.
Toxicokinetics examines how substances move through a biological system, including absorption, distribution, metabolism, and excretion, making this guidance significant for regulators and manufacturers assessing particle safety.
The inclusion of inhalation and oral exposure pathways reflects the real-world routes through which humans are most commonly exposed to industrial and manufactured particles in occupational and consumer settings.
OECD has been transparent about the limitations of the document, stating that its scope was based on what was considered feasible given the available scientific data at the time of writing.
The organisation has indicated it may issue future updates or additions as new scientific information becomes available and is structured in a way that supports further guidance development over time.
The publication forms part of a broader international effort to develop robust, science-based frameworks for assessing the safety of increasingly complex chemical and nanomaterial substances.
Regulatory bodies and industry stakeholders working with manufactured particle technologies are expected to consult the document as part of compliance and risk assessment processes going forward.