What are the four phases of pharmacokinetics?

The correct response identifies the four essential phases of pharmacokinetics: absorption, distribution, metabolism, and excretion.

Absorption refers to the process by which a drug enters the bloodstream from the site of administration. This phase is crucial as it affects the onset of the drug's action and is influenced by factors such as the route of administration and the drug's formulation.

Distribution involves the dispersion of the drug throughout the body's fluids and tissues. This phase determines how effectively the drug reaches its site of action, and factors such as blood flow to the tissues and the drug's ability to cross cellular membranes play significant roles.

Metabolism, often occurring in the liver, is the body's method of chemically altering the drug, usually resulting in its inactivation or preparation for elimination. This phase can affect the duration and intensity of the drug's action.

Lastly, excretion is the process of eliminating the drug from the body, primarily via the kidneys, but also through bile, sweat, or exhalation. This phase is vital for clearing the drug from the system, preventing potential toxicity.

The other options provided do not accurately represent all four phases of pharmacokinetics. For instance, the inclusion of "synthesis" or "elimination" does not