Goals of Tox21: The goal of the Tox21 program is to develop approaches, which are efficient and take less time to predict how chemicals may impact human health and the environment. Initially, the focus of Tox21 is to help prioritize chemicals for further in-depth toxicological evaluation using traditional methods. The Tox21’s focus is to develop new strategies for toxicity testing that would depend less on animal models and more on in vitro studies to evaluate the effects of chemicals on biological processes (Collins et al., 2008; Tice et al., 2013).
To fulfill this objective, the goals of the Tox21 program are to:
Design, develop, validate, and translate new in vitro methods to evaluate the effects of chemicals on important steps in toxicity…show more content… Although animal models can be helpful in predicting toxicity in humans, they have some negative characteristics and are not always the best choice (Bracken, 2009). The main disadvantages of animal experiments include: they are often very time consuming - e.g. the 2-year rat bioassay for carcinogenicity (Eduati et al., 2015); they are costly - e.g. $3 billion a year spent worldwide (Bottini and Hartung, 2009); and not reliable in some cases - e.g. about 20-30% of adverse effects are not detected during preclinical testing (van Vliet, 2011). For in vivo toxicity testing, animals are often given high maximum tolerable doses, which is in most cases opposite to the real-life situation where humans are exposed to low doses over longer periods of time (Krewski et al., 2009). Animal experiment design may lead to inaccurate predictions, and consequently, the loss of valuable chemicals for industry (Hartung, 2009). Furthermore, there are many adverse effects, such as autism, for which there is no animal model…show more content… The human health risk assessment requires an understanding of the molecular basis of hazard, Tox21 allows obtaining a deeper understanding of mode of action, faster than ever before (Roggen, 2014). This test method has an ability to provide information relatively less costly and more quickly about potentially dangerous substances for health and regulatory authorities, and others, so they can make decisions faster to protect public health and this strategy is also seen as the best hope for evaluating the huge backlog of chemicals for which there is not toxicity data available (Kavlock et al., 2009). Another important advantage of this testing approach is its capability to test several doses, specifically in the low-dose range of the dose-response curve where concentrations are most relevant to real life human exposures (Krewski et al.,
