Glossary of Clinical Terms

1️⃣ Zero-order elimination kinetics is a type of pharmacokinetic process that describes the rate at which a drug is eliminated from the body. In zero-order elimination, the rate of drug elimination is constant over time, meaning that a fixed amount of drug is eliminated per unit of time, regardless of the drug concentration in the body. This is in contrast to first-order elimination kinetics, where the rate of elimination is proportional to the drug concentration in the body, and the rate of elimination decreases as the drug concentration decreases.

2️⃣ The principle of Zero order kinetics is applied in the development of time-release preparations such as sustained-release or extended-release formulation. In such products, the release of an active drug from the dosage form is constant at a particular time and makes the drug available in the body systems over a longer period. In such dosage forms, the drug is eliminated by a process that is saturated, meaning that the enzymes responsible for drug metabolism or the transporters responsible for drug excretion are working at their maximum capacity. As a result, the rate of drug elimination is not affected by changes in the drug concentration, and the elimination process is independent of the drug concentration. At the same time, the time release preparation continues to release the drug from its matrix, maintaining therapeutic concentration in the circulatory system, thereby providing extended therapeutic activity.

3️⃣ The use of time-release preparation reduces the frequency of ingestion of the medicine such as instead of taking 2 tablets a day, one can get the same benefit by ingestion of a single extended-release preparation containing the same active drug.