Pharmacokinetics is a science that applies the principles of kinetics to study the changes of drugs in the body, namely the speed of processes such as drug absorption, distribution, biotransformation and excretion.

Pharmacokinetics is the study of drugs in vivo using mathematical models and formulas.

Absorption rate constant (Ka)

It indicates the rate at which the drug is absorbed into the large circulation at the site of application.

When the Kα value increases, the peak value of the blood drug concentration also rises, but the peak time decreases.

2. Absorption Fraction (F)

It represents the ratio of the amount of the drug entering the systemic circulation to the dosage used.

The F of intravenous injection is 1; The F value for oral administration or intramuscular injection is ≤1. When taken orally, the F value is related to diet and the time of medication.

3. Apparent Volume of Distribution (V

It indicates the degree to which the drug is distributed in the body.

When administered intravenously, V= dose (D) /C; When the V value increases, the drug concentration decreases, and the two are inversely proportional.

4. Eliminate the velocity constant (K)

It indicates the rate at which a drug is metabolized and excreted in the body, representing a fixed fraction or percentage of the drug that the body can eliminate within a unit of time.

That is, the ratio of the amount of medicine eliminated within a unit of time to the initial amount of medicine in the body. It is determined by the process of drug metabolism and excretion

The unit is the reciprocal of time

K is an important parameter reflecting the speed at which drugs are eliminated in the body. Collected and sorted by Medical | Education Network.

When the K value increases, the drug elimination accelerates and the blood drug concentration decreases.