Which of the following is an example of an excipient?

The choice of tablet binder as an example of an excipient is accurate, as excipients are substances that are included in a drug formulation to aid in the manufacturing process or enhance the properties of the final product without exerting therapeutic effects themselves.

A tablet binder acts as a glue that holds the active ingredients and other components together, ensuring the tablet maintains its shape and integrity. This is crucial for the formulation's consistency, stability, and ease of handling.

Active pharmaceutical agents, on the other hand, are the components responsible for the therapeutic effect of the medication, thus not fitting the definition of excipients. Preservative agents can serve as excipients in some formulations, but they are primarily included to prevent microbial growth rather than to aid in the structure or delivery of the active ingredient in the same way that a binder does.

Therefore, while tablet binders are quintessential examples of excipients due to their functional purpose in drug formulation, active pharmaceutical agents do not qualify, and while preservatives can be excipients, they have a different primary role compared to binders. The focus on tablet binders as the clear example aligns directly with the core definition of what constitutes an excipient.