What is the process called when drugs move from higher concentration to lower concentration?

The correct answer identifies passive diffusion as the process through which drugs move from an area of higher concentration to an area of lower concentration. This movement occurs spontaneously and does not require energy input. In biological systems, this process is crucial for the absorption of medications across cell membranes, allowing substances to spread and balance their concentration levels within different compartments of the body.

Passive diffusion takes advantage of the natural kinetic energy of molecules. As substances tend to disperse evenly in a solvent, they move down their concentration gradient until equilibrium is reached. This property explains why many medications can be absorbed effectively when taken orally; they passively diffuse across the intestinal lining into the bloodstream.

Understanding this concept is important in pharmacy, as it influences how drugs are formulated and administered, knowing that some medications will require different strategies if they cannot cross membranes through passive diffusion effectively.