Considerations for Applying Route-to-Route Extrapolation to Assess the Safety of Oral Exposure to Substances

Area of Science:

• Toxicology
• Risk Assessment
• Pharmacokinetics

Background:

• Oral toxicity studies are crucial for evaluating the safety of food ingredients and additives.
• Data gaps in oral toxicity studies necessitate alternative assessment methods.
• Non-oral toxicity data can be utilized to bridge these gaps.

Purpose of the Study:

• To provide a commentary on the utility of route-to-route (R-t-R) extrapolation for oral safety evaluations.
• To emphasize the importance of toxicokinetic (TK) and toxicodynamic (TD) data in R-t-R extrapolation.
• To discuss the application of R-t-R extrapolation when oral toxicity data is insufficient.

Main Methods:

• Review of existing literature and principles of R-t-R extrapolation.
• Analysis of the role of TK and TD data in comparing oral and non-oral exposure routes.
• Case-by-case consideration of R-t-R extrapolation applicability.

Main Results:

• R-t-R extrapolation is a viable approach when oral toxicity data is unavailable or inadequate.
• Successful R-t-R extrapolation hinges on substance-specific TK and TD data comparison.
• The method requires careful consideration of toxicokinetics and systemic toxicity.

Conclusions:

• R-t-R extrapolation can effectively support oral safety assessments.
• TK and TD data are essential for the scientifically sound application of R-t-R extrapolation.
• This approach offers a valuable tool for risk assessment of substances with limited oral exposure data.