During which process do drugs typically move from an area of low concentration to high concentration?

The process by which drugs move from an area of low concentration to high concentration is known as active transport. This mechanism is essential for transporting substances against their concentration gradient, which requires energy. In biological systems, this energy is often supplied by ATP (adenosine triphosphate).

Active transport is crucial for maintaining concentrations of various ions and molecules within cells, ensuring that essential nutrients can be accumulated and toxins can be expelled even when those substances are more abundant outside the cell than inside. This contrasts with processes like passive diffusion, facilitated diffusion, and simple diffusion, where substances move from an area of higher concentration to an area of lower concentration without expending energy. Understanding active transport is vital for comprehending drug absorption and distribution in the body, especially for medications that need to enter cells to exert their therapeutic effects.