Toxicokinetics (TK) is a term used to describe the analysis of analyte concentration data collected during pre-clinical or nonclinical safety/toxicology studies conducted in animals. The primary goal of TK is to correlate findings of toxicity with a corresponding level of drug exposure using the primary endpoints of maximum concentration (Cmax) and the area under the curve (AUC).
In Toxicokinetic Analysis:
- Valuable data that guides further nonclinical development strategy and influences clinical development strategy (e.g., dose selection, etc.) is generated
- Dose proportionality, gender differences, and exposure comparisons following single and repeat exposure to the investigational drug are generally assessed
- The TK arm of a nonclinical toxicology study generally has fewer timepoints and fewer subjects and endpoints compared to nonclinical and clinical PK studies
- Half-life (t1/2) may not be accurately determined in TK studies (although it is frequently estimated) due to sparse blood samples collected for concentration-time analysis
- Animals used for TK blood collection are frequently distinct from those used for collection of toxicology data, to avoid any impact of the sampling schedule on toxicology findings (with exceptions for larger animals)