Assessing the pharmacological parameters are quite essential during all stages of drug discovery. The key focus of a pharmacokinetic evaluation is determining the fate of medication right from its entry into our system to its final exit. The four processes encompassing a pharmacokinetic assessment of any drug product involves – absorption, distribution, metabolism, and excretion. The efficacy of each of these processes relies on what route of administration you prefer to administer the product under evaluation and to what effect, it leads to changing the functionality of your internal organs.
What Is Pk Analysis?
Pharmacokinetics or pk assay is a branch of pharmacological sciences that is entirely dedicated to an evaluation of a substance administered to a living organism. Such substances may come from varied classes such as food additives, pharmaceutical drugs, cosmetics, and pesticides. Pharmacokinetics involves chemical metabolism of the administered substance from the moment of its administration to the point of its elimination.
An appropriate set-up of pharmacokinetic study design is a crucial parameter for obtaining the correct information. Before the start of such studies, it is the responsibility of the principal investigator to focus on the individual variation and selection of an optimum number of study volunteers. It is also essential to keep a check on the frequent blood collection schedules from the volunteers.
For the expected clinical usage as well as the properties of the investigational product should be defined after evaluating pk analysis results between standard healthy volunteers and others, showing differences in their pharmacokinetic profiles from these healthy volunteers. People with different pharmacokinetic profiles may be inclusive of children, elderly, patients suffering from the renal and/or hepatic disorders, and those with decreased drug-metabolizing activity.
ADME characterization – an essential parameter of pk assay –
Any drug administered to a human being is first pre-clinically and clinically evaluated based on its ADME profiling. Here’s an overview of the ADME characterization involved in pk analysis –
Absorption –
The study of the drug absorption is dependent on the route of administration that is intended for clinical use. Information about the change in concentration of the drug substance in plasma, whole blood, or serum levels is obtained here.
For all those drug products which show their efficacy through systemic circulation, it is important to quantitate the pharmacokinetic parameters such as bioavailability, systemic circulation, and absorption rate. For drugs to be taken orally, the bioavailability and absorption ratio of the drug under analysis, along with its first pass effect should be taken into consideration.
Distribution –
How a drug is being distributed throughout the system of the human subjects is mainly dependent on the changes observed in the overall drug concentration. Here, it is essential to consider both the plasma protein binding ability and drug partition ratio to the blood cells.
Metabolism –
By measuring the concentration of the investigational drug substance and its metabolites in urine, feces, and blood, it is possible to trace its pathway and rate of metabolism.
Excretion –
With the help of observances for the total drug clearance from the system, it can be understood that whether a drug has undergone systemic clearance through renal clearance or hepatic clearance.
