General TTC Concept

So far, two principal approaches exist in the thresholds developed to date the general TTC concept and the TTC concept in relation to structural information and/or metabolic and toxicological data of substances. 

The general TTC concept, covering also carcinogenic effects, was introduced by Rulis (1986, 1989) as a Threshold of Regulation. Rulis used data on a subset of 343 oral carcinogens from animal smdies compiled in the Carcinogenic Potency Database (CPDB) (Gold et al. 1984). 

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Kroes et al. (2000, 2004) and Barlow (2005) combined the general TTC concept and the stmcture-based, tiered TTC concept to develop an enhanced stmcture-based, tiered TTC approach. 

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