2. Distribution: where does a chemical substance go in the body?

2.1 Distribution phenomenon

Bioavailability is the ability of a substance to cross physiological barriers, enter the bloodstream, be distributed throughout the body and come into contact with the various organs.

In general, the initial phase of distribution is via the bloodstream, while distribution to the organs is largely determined by its affinity with them.

• Lipophilicity favors distribution to territories rich in lipids or phospholipids (supporting fats, nervous system, bone marrow, etc.).

• Hydrophilicity directs products to richly vascularized areas (heart, muscles, skin, etc.).

Some substances concentrate selectively in particular organs...