Which process is NOT part of pharmacokinetics?

Pharmacokinetics refers to the study of how a drug moves through the body, encompassing four main processes: absorption, distribution, metabolism, and excretion. Each of these processes describes a different aspect of how a drug is handled by the body after it is administered.

Desensitization, while it may involve changes in the body's response to a drug over time, does not fall within the pharmacokinetic framework. Instead, it is often more related to pharmacodynamics, which deals with the effects of the drug on the body and how the body responds to the drug.

In summary, the correct identification of desensitization as not being a part of pharmacokinetics stems from its focus on response rather than the movement and processing of drugs within the body.