In compounding, which term describes a substance added to a solution to expedite mixing?

The correct choice is emulsifier. In compounding, an emulsifier is a substance used to stabilize and expedite the mixing of two immiscible liquids, such as oil and water. Emulsifiers promote the uniform dispersion of these components, preventing them from separating and ensuring a stable product. This is particularly important in formulations like creams or lotions, where a smooth and consistent mixture is required for effectiveness and patient acceptance.

Understanding the roles of other substances helps clarify why the emulsifier is the correct choice. A solvent is typically a liquid that dissolves a solute to form a solution, but it does not specifically aid in facilitating the mixing of immiscible substances. A stabilizer is meant to maintain the physical and chemical stability of a compound but does not directly facilitate the mixing process. An excipient is an inactive substance that serves as the vehicle or medium for the active ingredient in a medication but does not necessarily expedite mixing. Therefore, emulsifiers play a crucial role in achieving proper blending in certain formulations, making them essential in the compounding process.