Which of the following properties is NOT impacted by the mode of administration of drugs?

The correct answer is that the chemical composition of a drug is not impacted by the mode of administration. The chemical composition refers to the molecular structure and the specific components of the drug itself, which remain unchanged regardless of how the drug is administered. This means that whether a drug is taken orally, injected, or administered through a patch, its inherent chemical properties do not alter.

In contrast, other properties such as bioavailability, onset of action, and adverse effects are influenced by the route of administration. For example, bioavailability can vary significantly depending on whether a drug is given intravenously (where it reaches systemic circulation directly) versus orally (where it may be metabolized by the liver before reaching the bloodstream). Similarly, the onset of action can differ; intravenous administration typically provides a faster onset compared to oral, due to quicker absorption into the bloodstream. Adverse effects can also vary based on the administration route, as different routes may lead to different absorption rates and distribution within the body. Thus, while the mode of administration can affect a drug's pharmacokinetics and pharmacodynamics, the fundamental chemical composition remains constant.