No-observed-adverse-effect level

NOAEL ( No Observed Adverse Effect or undocumented Level ) is a toxicological endpoint in the toxicity determination.

The NOAEL is the highest dose or exposure concentration of a substance in subchronic or chronic studies in which no significant increase in adverse treatment- related findings in the morphology, function, growth, development or life span are observed. In contrast, the NOEL indicates the dose at which no effect is observed.

The NOAEL for a substance always relates to a particular biological measurement method with a specific application form and a specific species or a specific cell culture system can be used in various processes a substance thus have different NOAELs. Many published NOAEL values ​​are based on subchronic toxicity studies with oral administration in rodents.

The problem with the nature of the NOAEL determination that normally receives only a single value of a given dose range in the NOAEL determination. In other, more complex methods as the benchmark process, all values ​​of the entire dose-response curve to be included by means of statistical methods.

The NOAEL is in preclinical pharmaceutical research an important toxicological endpoint, since there is usually based on allometric scaling and the inclusion of a safety factor, the maximum recommended starting dose ( Maximum Recommended Starting Dose, MrsD ) is determined for the first in man clinical trials from the NOAEL of the most sensitive species.

Swell

• Pharmacology
• Toxicology