We take medicines when we fall sick. Have you ever wonder how absorption of medicine takes place ?
To understand this, you should know the four terms that are absorption, distribution, metabolism and excretion.
First stage - Absorption
First, the medicine comes in contact with stomach juice. If there is no food, then suddenly the medicine disintegrates and get dissolve in stomach juice. Most of the medicines are basic in nature and therefore enters the small intestine and get absorb there. After absorption, it will distribute.
Second Stage - Distribution
The distribution of medicine totally depends on the blood flow. Medicines will be distributed more in lungs, liver, kidneys or brain. If medicine is in free form, then it will diffuse easily there. Most of the medicines distribute in liver.
Third Stage - Metabolism
If medicine is lipid stable, then liver converts that into water soluble. So, that it can be easily secreted through wine. Liver circulates medicine in the active form in blood cells. After metabolism, the final product formed in liver is called Metabolite.
Fourth Stage - Excretion
After a certain period of time, medicines are filtered by a kidney and are excreted through urine.
Here is one interesting video from channel Merck Manuals which also explained the process: