Depends on the RDA of the active compounds as well as their toxicities. Otherwise there is no clear FDA guideline on this issue.

i think the question needs to be more specific. Toxicity assays should be performed for each compound

best wishes

Thank you very much, our honorable professor Mozafari. Indeed, there is no approved research that clarifies the concept of toxic concentrations. I will work on your advice and first determine the RDA then Toxic properties of the element and its compounds in general .. My best wishes.

Thank you prophesser Abdelraouf for your clarification about the assays for each compound .. I think this will be the best mechanism for determining the toxic concentration

Hi Ibtisam, I agree with Prof Elmanama, here you have a paper that might be useful for testing toxicology of nanomaterials. Greetings!

Greetings to you, Professoق Mayra and thank you very much for sending the research . I appreciate this to you so much.

thanks and respect to you.

I am not sure you may ask providers... It is almost a standard list.