Why are certain laboratory animals recommended for specific testing guidelines?

• A. They are the least expensive to use.
• B. They respond identically to all routes of administration.
• C. Their use is justified based on existing documented and reliable responses to the route of administration.
• D. They require the fewest resources to house.

Answer: (C)

When choosing which laboratory animals to use for a specific testing route, the key idea is to rely on existing, well-documented evidence about how that species responds to that route. This shows that the animal model has predictable pharmacokinetics and toxicological or physiological reactions that are relevant to the route being studied, so the results are scientifically meaningful and ethically justified. Simply picking the least expensive option, assuming all routes affect the species the same, or prioritizing housing convenience does not provide the necessary justification for a specific route, because different routes can produce different absorption, distribution, and effects across species. In short, the recommended animal is one whose documented and reliable responses to the administration route support valid interpretation of the study outcomes.