Protein binding decreases the free drug concentration available for distribution, as only unbound drugs can exert pharmacological effects.

The primary barrier to drug absorption in the gastrointestinal tract is the epithelial cells that line the gut, which must be crossed for absorption to occur.

Most drugs are distributed throughout the body primarily by passive diffusion, moving from areas of higher concentration to lower concentration.

Drugs are primarily absorbed in the gastrointestinal tract through passive diffusion, which allows for the movement of drugs from an area of higher concentration to an area of lower concentration.

Bioavailability refers to the fraction of an administered dose of unchanged drug that reaches the systemic circulation.

The color of the drug does not significantly affect drug absorption, while pH, surface area, and molecular weight are critical factors.

Increased intestinal motility can lead to decreased drug absorption as it reduces the time available for the drug to be absorbed.

All of the above factors can significantly affect the volume of distribution of a drug, as they influence body composition and drug binding.

High lipid solubility enhances drug absorption as lipophilic drugs can easily cross cell membranes.

Intravenous administration results in the highest bioavailability since the drug is delivered directly into the systemic circulation.