Final answer:
The phase in Toxicity and Risk Assessment that evaluates the relationship between dose and likelihood of adverse effects is Dose-Response Assessment.
Step-by-step explanation:
In the context of Toxicity and Risk Assessment (Quantitative), the phase that involves evaluating the relationship between the dose of a substance and the likelihood of adverse effects is C) Dose-Response Assessment. This phase is critical as it examines how different levels of exposure relate to the occurrence and severity of potential health risks. The data acquired during this phase is typically represented in a dose-response curve, which is instrumental for understanding the dose at which a substance starts to become harmful and helps in establishing safe exposure levels. Determination of a clear dose-response relationship is essential not only to characterize the potential risks but also to inform regulatory guidelines and drug labeling.
During pharmacokinetic evaluations in drug development phases, particularly in non-clinical toxicity studies, toxicokinetics accomplishes a similar goal by describing systemic exposure in animals in relation to dose and the temporal pattern of the study. These findings are then used to predict the safety and risk in humans, thus toxicokinetics is an integral part of assessing the drug's safety profile before commencing with first-in-human clinical trials.