Final answer:
(d) Distribution is the process by which medication is delivered to the target cells and tissues after being absorbed into the bloodstream. This phase is crucial for determining the efficacy of a drug, along with absorption, metabolism, and excretion, which are collectively known as the ADME characteristics.
Step-by-step explanation:
The process by which medication is delivered to the target cells and tissues is known as distribution. This pharmacokinetic phase concerns the transport of drugs throughout the body after they are absorbed into the bloodstream. Drugs can cross various barriers, such as cell membranes and binding proteins, ultimately reaching their target sites. Absorption refers to the uptake of the drug into the bloodstream, usually after oral administration, while metabolism is the process by which the drug is chemically altered by the body's enzymes, primarily in the liver.
The efficacy of a drug not only depends on its pharmacological potency but also on its ADME characteristics: absorption, distribution, metabolism, and excretion. The correct answer to the question is that distribution is the process by which the medication is delivered to the target cells and tissues.