What does absorption refer to in pharmacology?

Absorption in pharmacology specifically refers to how drugs move from the site of administration into the bloodstream. This process is critical because it determines how quickly and effectively a drug will take effect after being administered. Various factors, including the method of administration (oral, intravenous, subcutaneous, etc.), the drug's formulation, and the presence of food or other substances in the body, can influence the rate and extent of absorption.

Understanding absorption is essential for determining the proper dosage and timing for medications, as well as for predicting their therapeutic effects and potential side effects. It establishes the groundwork for the drug’s bioavailability, which is the fraction of the administered drug that reaches systemic circulation.

In contrast, the other options address different pharmacological concepts. The breakdown of drugs refers to metabolism, while the removal of drugs from the body is related to excretion. The movement of drugs from the bloodstream to tissues represents distribution. Each of these processes plays a role in pharmacokinetics, but absorption is specifically focused on the transition from the site of entry into the systemic circulation.