Absorption describes what process?

• A. The passage of a drug into the bloodstream from the site of administration
• B. The transportation of the drug from the bloodstream to the body tissues and intended site of action
• C. Biotransformation of the drug into a water-soluble compound
• D. The body's way of removing waste products

Answer: (A)

Absorption is the movement of a drug from its administration site into the bloodstream, which determines how much and how quickly the drug becomes available to produce an effect. This step begins the drug’s action—without entering the blood, the drug can’t reach its site of action. After absorption, the drug can be distributed to tissues, then metabolized, and finally excreted. The other processes describe later stages: distribution moves the drug from blood to tissues; metabolism is the chemical change to a more water-soluble form; excretion is the removal of the drug from the body. Factors like the route of administration, solubility, formulation, and blood flow at the site influence how much drug is absorbed and how fast it happens.