Pharmacokinetics (PK) analyzes and describes the drug disposition in the body. PK sample analysis is based on the mathematical description of bodily processes, defined as absorption, distribution, metabolism, and elimination (ADME). Pharmacokinetics is closely related to other domains of pharmacology, such as pharmacodynamics and toxicokinetics.
Pharmacokinetics and pharmacodynamics are intertwined with each other. However, both of them are different. Pharmacokinetics study explains what the body does to a pharmaceutical drug, while pharmacodynamics describes the effect a drug has on the body. Both pharmacokinetics and pharmacodynamics are crucial for assessing the safety and efficacy of a drug product. The current article focuses on pharmacokinetic services and how PK labs can help accelerate drug development studies.
Pharmacokinetic services for drug discovery and development
Similar to LC-MS laboratories, PK labs focus on evaluating different characteristics of a drug product. Early drug discovery studies usually involve testing multiple compounds with the primary goal of target interaction with selectivity, specificity, and potency. PK labs perform early preclinical efficacy studies to determine the drug exposure required to achieve the desired efficacy. These early proof of concept studies help identify specific drug compounds, their systemic exposure in achieving efficacy, and the mechanism of action. PK labs also focus on in vitro assessments to study the potential metabolic stability of initial drug interactions and protein binding. These early assessments help filter out undesired drug compounds.
During late drug discovery stages, PK labs focus on lead compound optimization to select potential drug candidates for further preclinical toxicology and development studies. During this phase of drug discovery studies, PK labs often compare formulations and investigate additional effects and interactions using different species or study goals such as fed and fasted states or gender differences.
During preclinical drug development, the US FDA and other regulators require testing the drug compound in animal species to assess compound toxicity and early efficacy. Pharmacokinetic service providers employ both rodent and non-rodent animal species to test for early safety and efficacy data. Once an ideal compound satisfies all regulatory requirements and shows desired therapeutic effects in animal models, PK labs then focus on clinical studies.
Clinical pharmacokinetics assesses and predicts human PK data based on early animal studies. . Clinical PK data is crucial for relating drug dosage to systemic exposure. Initial clinical PK data is obtained by testing sub-efficacious doses in human volunteers. These studies may involve PK assessments as per dosing higher levels in study participants.
Clinical pharmacokinetic assessments are more complex and highly regulated than other studies. PK labs are well-versed and experienced in conducting clinical pharmacokinetic studies. They are highly regulated and comply with several GLP and GMP regulations. Often, drug developers rely on this expertise to gather early preclinical and clinical pharmacokinetic data. Besides, PK labs have deep knowledge of species selection for early PK evaluation and identifying the correct dose and route of administration during clinical pharmacokinetic assessments. In conclusion, pharmacokinetic studies are the foundational pillars for a successful drug development project. PK labs can transition a drug compound from early discovery studies to later stages of clinical trials and thus accelerate drug development initiatives.