Pharmacokinetics of Drug's
Pharmacokinetics is the study of absorption, distribution,
metabolism, and excretion of the drug; this is what the body does to the drug.
Pharmacology has two major broad branches; Pharmacokinetics and pharmacodynamics. Check out here what the Pharmacodynamicsof drug is?
The difference between Pharmacokinetics and Pharmacodynamics
is, Pharmacokinetics refers to the absorption, distribution, metabolism, and
excretion of drugs, and
Pharmacodynamics is concerned with molecular, biochemical,
and physiological effects of drugs, and their drug mechanism of action.
4 Steps of Pharmacokinetics
Drug pharmacokinetics refers journey of the drug through the body, during which it passes through four different phases; 1. absorption, 2. distribution, 3. metabolism, and 4. excretion of the drug (ADME).
Pharmacokinetics of drugs is the study of the movement of the drug into, through, and out of the body.
A=
Absorption
D= Distribution
M=
Metabolism
E= Excretion
Know are the different routes
of drug administration?
1. Absorption
It is defined as the passage of a drug group from the site of administration into circulation.
The drug reaches its
site of action and passes through various membranes and barriers depending upon
the route of administration.
Factor Affecting Absorption Process
These factors are-
1. Disintegration and dissolution time
2. Formulation
3. Particle size
4. Liquid solubility
5. Area and vascularity of absorbing surface
6. PH of medium
7. Gastrointestinal motility
8. Presence of food
9. Metabolism
10. Certain Disease condition
Mechanism of Drug Absorption
Passage of drug through the cell membrane to reach its site of action.
There is a different way of the mechanism of drug
absorption –
1. Passive diffusion
2. Filtration
3. Facilitated diffusion
4. Active transport
5. Endocytosis
6. Pinocytosis
2. Distribution
It is the process of movement or delivering a
drug throughout fluid to the tissue of the body, where its action is
needed.
It should cross different barriers before reaching
the site of action after a drug reaches the systemic circulation.
3. Metabolism
Metabolism of the drug is the process of biochemical alteration of the drug in the body. It is also called biotransformation.
The body treats most drugs as a foreign substance and
tried to inactive or eliminate them by the various biochemical reactions.
Drug metabolism also depends upon the water solubility of a
drug.
Site of Metabolism
The most important organ of biotransformation is
the liver, the primary site of drug metabolism, but Drugs are also metabolized
by kidneys, gut mucosa, lung, blood, and skin.
4. Excretion or Elimination of Drug
The drug is excreted from the water-soluble metabolites (a substance produced during metabolism), the product that remains after a drug is broken down (metabolized) by the body.
And some drug is directly eliminated (unchanged) without metabolism.
Major Organ of Excretion
The Major Organ of Excretion is -
1. Kidney: renal excretion
2. Intestine
3. Billary excretion
4. Lung: Pulmonary Excretion
The drug is also excreted in a small amount in
the-
1. Urine
2. Stool
3. Mammary excretion
4. Skin Excretion
5. Salivary Excretion
6. Tears
Know here 10
rights of drug administration to prevent administration of medication error.
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