Tailor-made Inhalation Toxicity Study
Inhalation toxicity studies are crucial for meeting regulatory requirements and scientifically validating product safety. Drawing on our extensive experience and technical expertise, we provide customized study designs tailored to the properties, intended uses, and expected human exposure pathways. Even when the purpose of the study is not clearly defined, we work closely with our clients to develop an optimal study strategy. Our services address a range of objectives, including regulatory compliance, product risk reduction, and accumulation and utilization of product safety information within your organization. Please feel free to contact us even in the early stages of your study planning.
Our Contract Achievements
Our strength lies in our diverse know-how gained through abundant experience. We are pleased to present selected contract achievements from our inhalation toxicity studies.
| Species | Route | GLP | Single dose | 2W | 4W | 13W | Others |
|---|---|---|---|---|---|---|---|
| Monkeys | Head-only inhalation exposure | OECD GLP | 0 | 0 | 0 | 0 | 0 |
| Pharmaceutical GLP | 1 | 0 | 0 | 2 | 0 | ||
| Non-GLP | 1 | 1 | 0 | 0 | 0 | ||
| Mice | Whole-body inhalation exposure | OECD GLP | 0 | 0 | 0 | 0 | 1 |
| Pharmaceutical GLP | 0 | 0 | 0 | 0 | 0 | ||
| Non-GLP | 2 | 0 | 0 | 0 | 3 | ||
| Rats | Nose-only inhalation exposure | OECD GLP | 70 | 0 | 6 | 3 | 0 |
| Pharmaceutical + OECD | 4 | 0 | 0 | 0 | 0 | ||
| Pharmaceutical GLP | 4 | 0 | 1 | 2 | 0 | ||
| Other GLP | 3 | 0 | 0 | 0 | 0 | ||
| Non-GLP | 30 | 5 | 5 | 2 | 1 | ||
| Whole-body inhalation exposure | OECD GLP | 0 | 0 | 1 | 0 | 0 | |
| Pharmaceutical GLP | 2 | 0 | 2 | 0 | 0 | ||
| Non-GLP | 4 | 0 | 0 | 0 | 0 |
Overview of Inhalation Toxicity Study
Inhalation toxicity studies are non-clinical assessments in which test substances are administered via spontaneous respiration. These studies aim to evaluate the safety of substances that may be exposed to humans through the respiratory tract. The objective of these studies is to examine a wide range of substances, including pharmaceutical products intentionally administered via the respiratory tract, as well as various materials unintentionally inhaled in workplaces and home environments—such as agrochemicals, chemical products, household products, and emissions from electronic devices.
Therefore, regulatory authorities may require the conduct of inhalation toxicity studies, depending on the route of administration for pharmaceuticals, the physical properties of new active ingredients for agrochemicals, or the physicochemical properties and/or exposure scenarios for chemical products.
Main test substances
(Inhalation drugs, insecticides)
(Technical grade, formulations)
(Gas, volatile agents)
Household products* commonly used in our daily lives are also included as study subjects.
(Water-proof spray / Hair styling products / Antiperspirants / Deodorants)
*: Products that may be inhaled by humans due to emissions, including evaporation and spraying.
List of Inhalation Toxicity study
Mediford conducts a variety of inhalation toxicity studies in compliance with GLP standards and can flexibly accommodate different combinations of test systems. For nearly 40 years, we have conducted a wide range of inhalation toxicity studies tailored to the specific characteristics of various substances, accumulating extensive experience and technical expertise in this field. Leveraging our decades of expertise, we deliver high-quality, end-to-end inhalation testing solutions—from atmosphere generation and characterization to detailed respiratory histopathology.
| Study type | Characteristics of test atmosphere | Species | Exposure route |
|---|---|---|---|
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Types of Equipment
Inhalation toxicity studies require a high level of expertise in both the selection and use of equipment. We provide best practices by ensuring the appropriate configuration and use of equipment, backed by years of technical expertise and experience.
Test atmosphere preparation
Test atmosphere exposure
Test Atmosphere Characterization
We provide reliable test atmosphere characterization, backed by extensive expertise and a proven track record. We deliver highly accurate data for all aspects, including precise control of exposure concentration, particle size distribution, and environmental conditions.
Exposure concentration measurement
Gravimetric analysis method:
- Sample collection using a glass fiber filter
- Measurement of collected air volume
- Measurement of filter weight before and after collection
Chemical analysis method:
- The concentration of the test substance in the test atmosphere is quantified by chemical analysis (e.g., gas chromatography or high-performance liquid chromatography) as an alternative to gravimetric analysis.
Highly reliable data obtained through these methods are ensured by thorough validation.
Validation items:
- Collection efficiency, recovery rate, weighing suitability, adsorption and permeability
- Test atmosphere sampling
(suction-based method) - Sampling volume measurement
- Gravimetric analysis
or
Chemical analysis
Particle size distribution
In inhalation toxicity studies, particle size is measured as aerodynamic diameter, which is an important index to particle deposition in the respiratory tract. These results are used to evaluate the location and quantity of particle deposition in the respiratory tract.
Calculated parameters:
- Mass Median Aerodynamic Diameter: MMAD
- Geometric Standard Deviation: GSD
Measurement of aerodynamic diameter.
Equipment: Cascade impactor
A cascade impactor is a device used to collect and classify airborne particles by sequentially passing them through multiple stages. Each stage consists of a nozzle (jet) and an impaction plate (sampling plate). The air velocity increases at each stage by sequentially reducing the diameter of the jet. Particles entering the impactor are separated by size as they are impacted onto plates due to increasing air velocity.
| Stage No. |
Cutoff diameter (μm) |
Sample weight ratio |
|---|---|---|
| 1 | 5.8 | 14.9% |
| 2 | 3.67 | 37.1% |
| 3 | 2.41 | 24.2% |
| 4 | 1.49 | 11.9% |
| 5 | 1.09 | 6.2% |
| 6 | 0.75 | 3.6% |
| 7 | 0.34 | 1.5% |
Environmental condition
Temperature and relative humidity are routinely measured, and oxygen concentration is also measured when low levels are expected.
Guidelines
We are capable of conducting a wide range of inhalation toxicity studies in compliance with both domestic and international guidelines. The data generated from our studies are suitable for submission to regulatory authorities.
Applicable guidelines
Acute inhalation toxicity study (single dose toxicity study)
- OECD guideline No. 403 (Traditional protocol)
- OECD guideline No. 433 (Fixed concentration procedures)
- OECD guideline No. 436 (Acute toxic class method)
- EPA health effect test guideline (OPPTS/OCSPP) 870.1300
Sub-acute inhalation toxicity study (28-day or 4-week repeated dose toxicity study)
- OECD guideline No. 412
Sub-chronic inhalation toxicity study (90-day or 13-week repeated dose toxicity study)
- OECD guideline No. 413
- EPA health effect test guideline (OPPTS/OCSPP) 870.3645
Regulatory Compliance
We propose study designs that comply with toxicity study guidelines, as well as the regulatory requirements of domestic and international authorities that require inhalation toxicity study data.
Major Regulatory Requirements:
- Acute inhalation toxicity test required when applying for exemption under the “Criteria for Determining Poisonous and Deleterious Substances” of the Poisonous and Deleterious Substances Control Act (Japan)
- Chemical Substances Control Law (Japan): A 28-day repeated inhalation toxicity test using mammals is required for notification of a new chemical substance
- European Regulations (CLP/REACH): Classification of inhalation toxicity based on the European Council Directive (EC) regarding hazard classification and labelling
- IMDG Code (maritime transport): Classification of inhalation toxicity based on IMO (International Maritime Organization) regulations for maritime transport of dangerous goods
- IATA Dangerous Goods Regulations (air transport): Toxicity data required for hazard classification and labelling during air transport, based on ICAO-TI and IATA-DGR