The authors aim to assist chemists during chemical development for consumer products, food contact substances, or other non-pharmaceutical uses, so that new commercial compounds will be entirely free from any hormonal activity. In order to achieve this they describe a detailed Tiered Protocol for Endocrine Disruption (TiPED) that can be used early on in the design of new compounds. Starting with Tier 1 computational assessment (in silico), the protocol spans across basic in vitro molecular level testing, cell-based assays to whole organism in vivo experiments using fish, amphibians and in Tier 5, mammals (rodents). While in silico tests can provide important information, the authors assert that such tests alone will not render sufficient certainty that the endocrine disruption hazard is not inherent to a compound. They emphasize the importance of conducting additional tests to confirm a substance to be hazard-free. The TiPED is said to cover all known aspects of endocrine disruption. This includes the fact that in silico and in vitro assays will not cover important aspects of whole organism effects, such as unknown pathways, metabolite action or prenatal, developmental toxicity. Therefore, the authors conclude that more costly and ethically controversial in vivo experiments are fundamentally required.
If a newly designed substance clears all tiers of the TiPED it can be assumed to be free from endocrine disruption, based on current scientific knowledge. The authors include lists of current suitable assays for all respective tiers. A website linked to the publication will contain the regularly updated, state of the science TiPED for common use.
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Read more in a blog post by two of the original study’s authors (4 February 2013).