Acute Toxic Class

Acute Toxic Class ( ATC ) is a method developed by the Federal Institute for Risk Assessment (BfR), Germany, to replace the LD50 method for testing substances for acute oral toxicity . With this method, the number of comparable applications with the LD50 method can be reduced by around 70 percent.

Four groups of three animals of one sex each are formed. The animals then receive a group via a stomach probe , an oral administration of 5, 50, 300 and 2000 mg / kg body weight (OECD Guideline 423, revised in 2001); an additional dose of 5000 mg / kg is possible, but depends on the experimental conditions. The duration of the experiment is 48 hours. If possible, start with a dose at which the first deaths occur. If no information on toxicity is known, a dose of 300 mg / kg body weight is started. If two or all animals die, the next lower dose is chosen for a new group of animals. If only one animal or no animal dies, the same concentration is administered again.

It usually takes two to four attempts to assess the acute oral toxicity of the test substance. In addition to the ATC test, two other methods are recognized by the OECD as a method for determining acute toxicity: the fixed dose method (FDP method) and the UDP method (up and down procedure).

See also : Section “Acute Oral Toxicity: Acute Toxic Class Method” in Toxicity Determination