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Evaluating lifetime risks

While they serve similar purposes, Acceptable & Tolerable Daily Intake (ADI & TDI) are often used in slightly different contexts and by different regulatory authorities. 

Acceptable vs. Tolerable daily intake

The ADI is typically applied to substances that are intentionally added to foods, such as food additives, whereas the TDI is primarily used for substances that are not deliberately added but are present due to contamination, environmental pollution, or as by-products of processing.


Both ADI and TDI are calculated by extrapolating from animal studies to surrogate human to surrogate toxicology human data using the No Observed Adverse Effect Level (NOAEL). 

Safety margin

Both ADI and TDI incorporate safety margins, established by dividing experimental threshold levels by uncertainty factors, to account for potential human variability and interspecies differences.


Toxicologists at IASON consulting possess advanced degrees in toxicology or related fields, combined with experience in risk assessment, making them qualified to calculate TDI and ADI values.

Regulatory background

Vaccine production line


This guideline pertains to "Impurities: Guideline for Residual Solvents". It provides guidance on the permissible levels of residual solvents in pharmaceuticals. The threshold values for various solvents are based on toxicity data.

ICH M7(R2)

This guideline, titled "Assessment and Control of DNA Reactive (Mutagenic) Impurities in Pharmaceuticals to Limit Potential Carcinogenic Risk", provides a framework to assess and control mutagenic impurities in pharmaceuticals. It allows for the estimation of threshold values based on compound-specific toxicity data and uses default safety factors. The guidance is especially known for its two complementary approaches: the threshold of toxicological concern (TTC) and compound-specific acceptable intakes based on linear extrapolation of tumorigenic potency.

DNA string
Flag of the European Union


This is the EMA (European Medicines Agency) guideline on the "Assessment of genotoxicity of covalent and highly reactive drug metabolites". While not directly focused on TDI / ADI, it does offer guidance on evaluating the potential genotoxic risk of metabolites in human pharmaceuticals, which can influence threshold values.

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