Pharmacokinetics (PK) in rodents is the quantitative study of the time course of drug disposition. It describes the fate of a xenobiotic compound within a living organism. This involves determining the concentration of the drug in systemic circulation and at its site of action over a given period, providing a foundation for understanding the relationship between drug dose, exposure, and effect.

Maximum tolerated dose (MTD) is the highest dose of a drug that doesn't cause unacceptable side effects or overt toxicity in a specific time period.
Determining the MTD during preclinical development is crucial for two main reasons: to ensure patient safety in future clinical trials and to guide the design of those trials.