Which substance is NOT typically classified as an inactive ingredient in a medication?

In the context of medication formulation, active pharmaceutical ingredients (APIs) are the primary components that provide the therapeutic effect of the medication. They are responsible for achieving the intended health benefit, such as relieving pain, treating infections, or addressing other medical conditions.

Inactive ingredients, on the other hand, serve various roles that support the formulation of the medication but do not contribute to its pharmacological efficacy. Flavorings, binders, and dyes are all examples of inactive ingredients. Flavorings enhance taste and improve patient compliance, binders help hold the tablet together, and dyes provide color for identification or aesthetic purposes.

Thus, since active pharmaceutical ingredients are the substances that impart therapeutic effects and are not classified among the inactive ingredients, that makes the answer correct.