Pharmacokinetics

Pharmacokinetics is a science that studies how drugs and their active components enter the body, are distributed to tissues and organs, are metabolized and excreted from the body. It plays an important role in the development of new drugs and optimization of existing therapeutic strategies.

Pharmacokinetic studies can be carried out as

Pharmacokinetics is a branch of pharmacology that studies the processes and dynamics of the distribution of drugs in the patient’s body after their administration, as well as the effect of drugs on the processes of metabolism and excretion. This is the basis for determining the dose and choosing optimal dosing regimens.

There are two main types of pharmacokinetics: excretion and absorption. Absorption includes the entry of a drug into the blood from the site of injection or ingestion, distribution to tissues and organs, and the onset of action of the drug. Excretion is associated with the process of metabolism and removal of a drug from the body.

For example, during excretion, the rate of elimination of a drug (both total concentration and in the form of metabolites) will depend on the activity of its metabolic pathway. Thus, in the case of microsomal enzyme inhibitors (such as chloramphenicol), this zone will be slower due to the slower metabolic pathway. On the other hand, non-oxidizable drugs will have a shorter plasma half-life because they will be eliminated with little to no metabolism.

For each drug, there are unique excretory reactions that can be caused by various factors, such as the person’s age, the health of organs and tissues, and the degree of functional activity of kidney and liver enzymes. For example, pharmacokinetics in children under 6 years of age usually differ from those in adults. Various kidney diseases and liver cirrhosis also affect pharmacokinetics. They may alter drug clearance, resulting in the need to revise dosages and/or modify treatment regimens accordingly.

As a scientific term, pharmaceutical kinetics arose after appropriate experiments were carried out on animals. Experiments were conducted to evaluate the effectiveness and safety of drugs. Later, these studies were summarized and the development of clinical trials began.

Pharmacokinetic properties determine the medicinal effect of a drug. Pharmacokinetic studies of drugs are an important element of the research and practical work of pharmaceutical companies and clinical laboratories.

Pharmacokinetics occupies a special place in the development of new dosage forms and the introduction of drugs into medical practice. In clinical trials of drugs, pharmacokinetic characteristics are studied.

Based on pharmacokinetic studies, possible metabolic pathways are determined; give recommendations on dosage regimens, a list of persons for whom a particular drug is not contraindicated; determine specific doses for different age groups; and etc.