Overview
ISO/TS 5387:2023 - "Nanotechnologies - Lung burden mass measurement of nanomaterials for inhalation toxicity tests" provides guidance on measuring the mass of nanomaterials retained in respiratory tissues after inhalation exposure. The Technical Specification supports interpretation of lung clearance behaviour, translocation and toxicokinetics of nanomaterials, and complements OECD inhalation test guidance by describing how to collect lung burden data and derive clearance parameters.
Key topics and technical requirements
- Scope and definitions: aligns terminology with ISO 80004 (nanotechnologies vocabulary) and defines terms such as aerodynamic diameter, MMAD, poorly soluble particles, nanoparticle, nanofibre, etc.
- Use of lung burden data for risk assessment: explains how retained dose informs lung overload hypotheses, macrophage clearance capacity, and read-across approaches.
- Inhalation exposure and sampling: guidance on aerosol generation, chamber monitoring, and tissue sampling strategies (single vs multiple lung lobes, post‑exposure observation points).
- Measurement methods: overview of available lung burden measurement approaches with specific guidance by material class:
- Carbon nanomaterials (e.g., nanotubes)
- Metal‑based nanomaterials
- Polymeric and other nanomaterials
- Kinetic modelling: procedures to derive clearance kinetics including one‑compartment and two‑compartment first‑order clearance models, and recommendations on sampling time points to obtain reliable kinetic parameters.
- Study design annexes: informative test‑scheme options for 28‑day and 90‑day studies (fast‑dissolving vs poorly soluble aerosols) and an annex describing measurement methods.
Applications
ISO/TS 5387:2023 is intended to:
- Inform inhalation toxicity test design for nanomaterials and support selection of lung sampling regimes.
- Provide data to calculate retained dose and clearance kinetics for risk assessment and human equivalent dose estimation.
- Support regulatory submissions where pulmonary effects drive hazard assessment (e.g., poorly soluble, low‑dissolution nanomaterials).
- Enable read‑across and cross‑study comparisons where external exposure and retained lung burden differ by particle size or composition.
Who should use this standard
- Toxicologists and inhalation study designers
- Regulatory agencies and risk assessors
- Contract research laboratories conducting inhalation tests
- Nanomaterial manufacturers and product safety teams
- Academic researchers studying pulmonary toxicokinetics
Related standards and guidance
Keywords: ISO/TS 5387:2023, lung burden measurement, nanotechnologies, nanomaterials, inhalation toxicity tests, lung clearance, toxicokinetics, poorly soluble particles.