Pharmacokinetic, by definition, is the study of drug movement through the body. It involves studying the absorption, distribution, metabolism, and excretion characteristics of a drug product. Both pharmacokinetics and pharmacodynamics are critical for assessing the safety and efficacy of a drug product. But to compare pharmacokinetics versus pharmacodynamics, PK studies what the body does to a drug while PD assesses what a drug does to the body.
As PK studies drug properties in living organisms, most PK analysis involves biological samples such as blood, serum, and plasma. A series of PK analyses give a window to peek into the information about the effects a drug may have on different body compartments. Besides, the applied PK drug data is not only useful for research or academic purposes but is also heavily used in drug dosing and therapeutic monitoring. Hence, understanding this importance, several CROs offer PK service packages to drug developing companies. Outsourcing PK studies aid by alleviating monetary pressures and completing additional drug testing needs. In the current article, we share three essential contributions of PK services to the drug discovery process.
PK services perform critical nonclinical pharmacokinetic studies.
Before beginning in-human clinical trials, CROs conduct several in vitro and in vivo studies. These studies include in vitro tests to evaluate the potential of a drug to interact with biological channels and animal tests to determine therapeutic action. Finally, sponsors conduct single-dose and repeated-dose toxicity testing to generate toxicokinetic data in animal models. PK data generated from this toxicity testing helps correlate the exposure levels with toxicity and qualitatively analyze how a drug will behave in the human body. Moreover, these studies are crucial in designing the primary doses of subsequent first-in-human studies.
PK services help conduct first-in-human trials.
The primary goal of first-in-human studies is to assess its safety and efficacy in trial participants. This initial study provides critical toxicity data, especially about risks associated with morbidity or mortality. The primary data from the animal study gives researchers an idea about drug toxicity and the levels at which they may occur. However, first-in-human studies are of utmost importance as they help confirm the toxicity levels in humans.
Single Ascending Dose and Multiple Ascending Dose (SAD/MAD) studies are vital first-in-human studies that generate critical early PK data for subsequent human trials. Single doses are administered in SAD studies, whereas MAD studies test multiple doses. Depending on the initial testing, researchers gradually increase the dosage to assess the drug’s therapeutic effects.
Conduct primary PK endpoint studies.
Once SAD/MAD studies help determine an acceptable safe dose, sponsors can then conduct additional Phase I studies. The studies have two objectives, one to collect PK endpoints and two to continue generating safety data. These studies include food effect studies, PK studies in special populations, drug-drug interaction studies, and radiolabeled drug studies. Sponsors test the drug product on a small population of subjects to assess the effects the drug, diseases, and patient characteristics will have on PK properties. Ultimately, evaluating these properties will help reduce risks to Phase 2 and Phase 3 patient populations and in subsequent marketing of the drug product.
