Pharmacokinetic Models and its Various Compartments

Description

Pharmacology's field of pharmacokinetics frequently abbreviated as PK, studies how drugs interact with live organisms after being induced to them. The phrase comes from the Ancient Greek words pharmakon, which means "drug," and kinetikos, which means "moving, setting in motion." Any chemical xenobiotic, such as pharmaceutical medications, pesticides, food additives, cosmetics, etc., are included in the compounds of interest. It makes an effort to understand how chemicals are metabolised and to determine what happens to a substance from the time it is supplied until the point at which the body completely eliminates it. Pharmacodynamics (PD) is the study of how a drug affects the organism, while Pharmacokinetics (PK) is the study of how an organism affects a drug. In PK/PD models, both together affect dose, benefits, and negative effects.

Pharmacokinetics explains how the body reacts to a certain xenobiotic or chemical after administration through the methods of absorption and distribution, as well as the metabolic changes the substance undergoes in the body (for example, by metabolic enzymes like cytochrome P450 or glucuronosyltransferase enzymes), and the effects and routes of the drug's metabolites' excretion. Drug dosage and administration techniques have an effect on a substance's pharmacokinetic properties. These may have an effect on the rate of absorption.

Noncompartmental or compartmental approaches are used to undertake pharmacokinetic modeling. Noncompartmental approaches calculate the area under the curve of a concentration-time graph to determine the drug exposure. Utilizing kinetic models, compartmental approaches estimate the concentration-time graph. Noncompartmental approaches are frequently more adaptable because they don't rely on a particular compartmental model to deliver reliable results that are also suitable for bioequivalence research. The results of a drug's changes in an organism and the laws that govern this outcome are dependent on a variety of interrelated aspects.

In order to make the study of pharmacokinetics simpler, a number of functional models have been created. These models are founded on the concept of an organism as a collection of connected compartments. Consider an organism as just one homogeneous compartment for the sake of simplicity. This model assumes that drug clearance is directly proportional to drug concentration in the organism and that blood plasma concentrations of the drug are an accurate reflection of the drug's concentration in other fluids or tissues.

Which compartment elimination takes place in will change this two-compartment model. Due to the liver and kidneys' adequate blood supply, elimination usually takes place in the central compartment. However, there are times when elimination might take place in both the peripheral compartment and the central compartment. The two compartment model has three potential variants, which may indicate that they might not completely account for all scenarios.

The multiple processes that take place when an organism interacts with a chemical substance have been conceptualized more easily using models. Monocompartmental models and two compartmental models are used most commonly since it is challenging to add parameters using that modeling approach. The multi-compartmental model is the most frequently used approximation to reality. The ADME scheme is the term used to describe the various compartments into which the model is divided.