Which term refers to an inert substance added to a drug to aid dosing?

• A. A primary active ingredient
• B. A flavoring agent that enhances taste
• C. A preservative
• D. An inert substance added to a drug to form a suitable consistency for dosing

Answer: (D)

Excipients are inert substances included in drug formulations to create the right dosage form. They don’t have therapeutic effects themselves but help with dosing by adding bulk, improving flow, and ensuring the active ingredient is distributed evenly. The described term matches this idea: an inert substance added to a drug to form a suitable consistency for dosing, such as fillers or diluents that make the dose easier to measure and administer. Flavoring agents affect taste, preservatives help with stability, and the primary active ingredient is the drug itself—together they aren’t about creating the proper dosing form like excipients are.