TK analysis is the subdivision of PK to test the relationship between systemic drug exposure and its toxicity in various species. Pharmacokinetic studies determine the systemic exposure of drug administration to living organisms over time after dosing. Toxicokinetic studies are generally carried out with higher doses as compared to pharmacokinetic studies. The objective of toxicokinetic studies is to quantify a compound’s pharmacokinetics in toxicological study species at toxicological doses. TK exposures may increase non-linearly with dosage due to absorption differences, metabolic saturation, or metabolic alterations resulting from the test article’s chronic usage. TK analyses are often used additionally to investigate drug accumulation with repeated dosing, gender differences, and quantitation of known drug metabolites or pharmacodynamic or toxicodynamic biomarkers.